Guidance for Evaluating Human Health Impacts in Environmental Assessment:

Noise DRAFT January 2011

Health Canada is the federal department responsible for helping Canadians maintain and improve their health. We assess the safety of drugs and many consumer products, help improve the safety of food, and provide information to Canadians to help them make healthy decisions. We provide health services to First Nations people and to Inuit communities. We work with the provinces to ensure our health care system serves the needs of Canadians.

This document may be cited as follows: Health Canada. (2011). DRAFT: Guidance for Evaluating Human Health Impacts in Environmental Assessment: Noise . Environmental Health Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario. Any questions or comments on this document may be directed to: Environmental Assessment Division 99 Metcalfe St, 11th Floor, A/L 4111A Ottawa, Ontario K1A 0K9 Fax: 613-960-4540 E-mail: [email protected] See also: http://www.hc-sc.gc.ca/ewh-semt/eval/index-eng.php Guidance for Evaluating Human Health Impacts in Environmental Assessment Series • The Basics • Drinking and Recreational Water Quality • Noise • Contamination of Country Foods • Radiological Impacts • Human Health Risk Assessment • Air Quality

Other documents in the Guidance for Evaluating Human Health Impacts in Environmental Assessment series can be found on the Environmental Assessment webpage at: http://www.hc-sc.gc.ca/ewh-semt/pubs/eval/index-eng.php

PREFACE This guidance is intended to provide assistance to stakeholders on specific information requirements to facilitate the preparation and review of environmental assessments in a consistent and effective manner. Alternative approaches to the principles and practices described in this document may be acceptable provided they are supported with adequate scientific justification. Please note that Health Canada may need additional information, not specifically described in this guidance when providing advice on human health impacts for a specific project. This guidance is intended to be advisory in nature and will be updated periodically based on revisions to current expertise, applicable standards and recommendations received from stakeholders. Readers are advised to ensure that they are using the most recent version available on the Health Canada website and that the use of human health risk assessments in an environmental assessment is reflective of current and best practices. This document is not to be considered a substitute for the guidance of a qualified professional practitioner. Health Canada encourages questions, comments or recommendations for improvements to this document, which may be directed to the following: Environmental Assessment Division 99 Metcalfe St, 11th Floor Address Locator: A L4111A Ottawa, Ontario K1A 0K9 Fax: 613-960-4540 E-mail: [email protected] See also: http://www.hc-sc.gc.ca/ewh-semt/eval/index-eng.php

TABLE OF CONTENTS 1

Acronyms ......................................................................................................................................................1

2

Purpose of This Document ..........................................................................................................................2

3

Introduction and Context ............................................................................................................................3

4

Roles and Responsibilities with Respect to Noise ......................................................................................4 4.1

5

6

7

Purpose of Health Canada Involvement in Noise Assessments in EAs ................................... 4

Health Impacts Associated with Noise Considered by Health Canada in Environmental Assessments 6 5.1

Noise-Induced Hearing Loss (NIHL) ...................................................................................... 6

5.2

Sleep Disturbance ................................................................................................................... 6

5.3

Interference with Speech Comprehension ............................................................................... 7

5.4

Complaints .............................................................................................................................. 7

5.5

High Annoyance ...................................................................................................................... 8

Suggested Approach for Assessing the Health Impacts of Noise ...........................................................10 6.1

Identification of Human Receptors in Project Areas ............................................................ 10

6.2

Characterization of Baseline Sound Levels at Receptors ..................................................... 11

6.3

Noise Assessment Methods and Health Effects ..................................................................... 14

6.4

Monitoring and Mitigation.................................................................................................... 19

6.5

Assessment of Residual Impacts ............................................................................................ 21

6.6

Assessment of Cumulative Effects ......................................................................................... 21

Noise Characteristics .................................................................................................................................22 7.1

Low-Frequency Noise ........................................................................................................... 22

7.2

Perceptibility ......................................................................................................................... 22

7.3

Tonal and Impulsive Noise .................................................................................................... 23

8

Community Consultation ..........................................................................................................................24

9

References ...................................................................................................................................................25

TABLES Table 6-1: Estimation of Baseline Noise Levels Using Qualitative Descriptions and Population Densities of Average Types of Communities ....................................................................................................................13 Table 6-2: Calculating Suggested Construction Noise MNL (based on EPA 1974) .........................................16 Table 6-3: Example of Applying Corrections to Establish a Suggested MNL for a Project in a Very Noisy Urban Community .........................................................................................................................................17 Table 6-4: MNLs Related to Number of Blasts ..................................................................................................17

APPENDICES APPENDIX A Glossary .....................................................................................................................................27 APPENDIX B Noise Impacts in EA Checklist ................................................................................................34 APPENDIX C Introduction to Noise and Health Effects of Noise ................................................................37 APPENDIX D Methodology (Equations and Format for Data Reporting) ..................................................42 APPENDIX E Identification and Characterization of Some Common Receptors ......................................54 APPENDIX F Commonly Applied Construction Noise Mitigation Measures and Considerations for Noise Reduction ..................................................................................................................................................55

APPENDIX TABLES Table D1 a) Determination of Baseline Leq (Day 07:00 – 22:00) with Applicable Sound Source and Character Adjustments ...................................................................................................................................................43 Table D1 b) Determination of Baseline Leq (Night 22:00 – 07:00) with Applicable Sound Source and Character Adjustments ..................................................................................................................................44 Table D1 c) Determination of Construction Leq (Day 07:00 – 22:00) with Applicable Sound Source and Character Adjustments ..................................................................................................................................46 Table D1 d) Determination of Construction Leq (Night 22:00 – 07:00) with Applicable Sound Source and Character Adjustments ..................................................................................................................................47 Table D1 e) Determination of Operational Leq (Day 07:00 – 22:00) with Applicable Sound Source and Character Adjustments ..................................................................................................................................48 Table D1 f) Determination of Operational Leq (Night 22:00 – 07:00) with Applicable Sound Source and Character Adjustments ..................................................................................................................................49 Table D1 g) Summary Table of Calculated Impact from Project Construction Noise (after all noise mitigation strategies are in place) on Magnitude of Community Reaction or Percentage Change in High Annoyance at Each Representative Noise Receptor.............................................................................................................50

Table D1 h) Summary Table of Calculated Impact from Project Operation Noise (after all noise mitigation strategies are in place) on Magnitude of Community Reaction or Percentage Change in High Annoyance at Each Representative Noise Receptor.............................................................................................................52

Guidance for Evaluating Human Health Impacts in EA: Noise

1 ACRONYMS Acronym AERCB ANSI CEAA or the Act CSA CTA dBA dBC dBZ EA EPA EUB FA % HA HHRA Hz ISO Ld Ldn Ln LSA MNL NIHL RA REDA RL RSA SEL TOR WHO

Meaning Alberta Energy Resources Conservation Board American National Standards Institute Canadian Environmental Assessment Act Canadian Standards Association Canadian Transportation Agency A-weighted decibels C-weighted decibels Z-weighted decibels environmental assessment Environmental Protection Agency (U.S.) Energy Utilities Board federal authority percent highly annoyed human health risk assessment Hertz International Organization for Standardization daytime sound level day-night sound level night-time sound level local study area mitigation noise level noise-induced hearing loss responsible authority Radiation Emitting Devices Act rating level regional study area sound exposure level terms of reference World Health Organization

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Guidance for Evaluating Human Health Impacts in EA: Noise

2 PURPOSE OF THIS DOCUMENT The purpose of this document is to guide stakeholders in their evaluation of human health effects related to noise in an environmental assessment (EA) and to facilitate understanding of comments made by Health Canada in the EA process. The Canadian Environmental Assessment Act (CEAA or the Act), aims to ensure that projects are considered carefully before federal departments/agencies take action in connection with them in order to ensure that such projects do not cause significant adverse environmental effects. The Act also aims to encourage departments that are the responsible authorities (RAs) to take actions that promote sustainable development and thereby achieve or maintain a healthy environment and a healthy economy. RAs are most commonly federal departments that provide funding, land, permits, licences or approvals for a proposed project. Federal departments may become RAs for physical works that they undertake (e.g. Health Canada constructing a new health care facility on a reserve). As defined in the Act, environmental effects include any effects of environmental changes caused by a project, including effects on human health. Health Canada’s role as a federal authority (FA) under the Act is to provide, upon request, scientific and technical advice on issues related to human health. FAs are most commonly federal departments or agencies that have expertise or a mandate relevant to a proposed project. This expertise, relating to human exposure to contaminants or other hazards (noise, radiation, etc.), is provided to assist RAs and/or provincial or territorial authorities in determining the significance of potential project-related human health effects. Health Canada can provide human health expertise concerning the following: • air quality effects • contamination of country foods (fish, wild game, garden produce, berries, etc.) • drinking and recreational water quality • radiological effects • electric and magnetic fields effects • noise effects • human health risk assessment (HHRA) and risk management • federal air, water and soil quality guidelines/standards used in HHRAs • toxicology (multimedia - air, water and soil) • First Nations and Inuit health • contaminated sites Health Canada does not possess expertise on modelling emissions and deposition, environmental fate and/or contaminant uptake by plants or wildlife. More information on Health Canada’s role in Environmental Assessment can be found on Health Canada’s website: http://www.hc-sc.gc.ca/ewh-semt/eval/index-eng.php

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Guidance for Evaluating Human Health Impacts in EA: Noise

3 INTRODUCTION AND CONTEXT Health Canada considers that a change in the sound environment that may impact human health be assessed as per the definition of an “environmental effect” provided in CEAA. However, Health Canada does not make decisions on the significance of these effects. This decision-making role rests with the RA or provincial/territorial authority. Health Canada’s role is limited to providing advice on the human health effects of noise based on well-accepted scientific evidence establishing a relationship between noise exposure and human health. There are reasonable cause-and-effect associations linking noise exposure to hearing loss, sleep disturbance, interference with speech intelligibility, noise complaints and a high level of annoyance (World Health Organization 1999). Health Canada’s advice is based on the expected changes between existing and predicted daytime and night-time sound levels (for construction, operation and decommissioning activities) at locations where people are or will be present, as well as on the characteristics of the noise (e.g. impulsive or tonal) or the type of community (e.g. urban, suburban or quiet rural areas). Health Canada does not provide advice on noise impacts on wildlife or ecosystems, or on occupational exposure to noise. This guidance reviews Health Canada’s role in noise assessment and discusses common human health impacts associated with noise exposure. The assessment of noise impacts and technical considerations in presenting information on various noise types and characteristics are discussed in detail. Prior to reviewing this document, the reader may wish to consult Appendix A (Glossary), which presents definitions of the technical terms used throughout. Appendices B through F contain additional technical and administrative information related to noise assessment in EAs.

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Guidance for Evaluating Human Health Impacts in EA: Noise

4 ROLES AND RESPONSIBILITIES WITH RESPECT TO NOISE In Canada, noise is managed by federal, provincial, territorial and municipal government legislation. Federal examples include Transport Canada (aircraft noise), the Canadian Transportation Agency (rail noise), and Human Resources and Skills Development Canada (specifically the Labour Program: occupational noise in workplaces under federal jurisdiction). Health Canada has a regulatory role via the Radiation Emitting Devices Act (REDA), which controls the sale of devices that create an unnecessary noise hazard or do not comply with regulatory standards. Health Canada’s expertise in acoustics may be provided to RAs under CEAA. Outside of these specific federal mandates, noise may be regulated directly through provincial and territorial legislation and guidelines, or municipal by-laws, which may apply broadly or only to specific project types or sectors. Few or many different criteria may be used to establish noise guidelines, such as levels of complaints from the public, interference with regular speech (conversation), and historical data concerning human health effects arising from noise. One of Health Canada’s roles concerning noise exposure is to review acoustical assessments for scientific validity to help ensure the informed management of the potential risks to human health from environmental noise. This goal is achieved via leadership in science, research, participation in national and international bodies that develop standards (e.g. the Canadian Standards Association (CSA) and the International Organization for Standardization (ISO)) and participation in the development of guidelines (e.g. the World Health Organization (WHO)) for noise and human health. Health Canada’s scientists conduct, evaluate and remain current on domestic and international scientific research pertaining to the human health impacts of noise. Their expertise is used to ensure that advice provided on the potential human health effects of noise is current. The responsibility for determining the significance of these effects rests with RAs as required by CEAA. Health Canada does not have enforceable noise thresholds or standards but can provide information based on widely accepted international standards (the U.S. Environmental Protection Agency (EPA), ISO, WHO, etc.) regarding the potential adverse human health effects of noise in an average population based on the type of community (e.g. urban, suburban or quiet rural areas). When noise levels have the potential to induce adverse human health effects, Health Canada may provide advice on mitigation measures that can be implemented to limit these impacts. HC encourages consultation with provincial authorities (i.e. provincial environment ministries and departments), territorial and municipal authorities, as appropriate, to determine which enforceable standards for noise exist for specific regions. Health Canada’s advice concerning human health effects related to noise exposure is based on internationally recognized standards (WHO, ISO, EPA, etc.), which are predictive of human health impacts. When mitigation measures are to be implemented, Health Canada advises that appropriate mitigation strategies based on all applicable guidelines be considered.

4.1

Purpose of Health Canada Involvement in Noise Assessments in EAs

This section is serves as an introduction to the approach taken by Health Canada when providing comments on project-related noise in the context of EAs. Human response to noise varies between individuals and according to the specific situation. This response to noise can be characterized using different methodologies and endpoints, and may include the consideration of several factors. These factors include how sound moves from source to receptor, how noise is measured and what physiological and/or psychological changes it evokes in humans. 4

Guidance for Evaluating Human Health Impacts in EA: Noise

A particular standard or guideline may not cover all possible considerations or the inherent variability in noise characterization. Several approaches to assessing noise impacts exist and often rely on different noise guidelines and/or regulations that may not be easily reconciled. For example, a guideline may be established to protect against hearing loss, but the consideration of additional human health endpoints, such as sleep disturbance, may also be warranted. Some guidelines and/or regulations are based on limiting absolute noise levels, whereas others emphasize the relative change in the noise environment. Upon written request from an RA, provincial or territorial authority, panel or mediator, Health Canada may provide information in Health Canada’s possession concerning the human health impacts of noise. This guidance document is intended to assist readers in understanding Health Canada’s comments regarding noiserelated human health impacts following the review of an EA, and to provide information on the calculations used for various human health endpoints in determining these potential impacts. Calculated impacts are necessary to understand the nature, extent and severity of human health effects that may occur due to project noise. These calculations also serve to evaluate the feasibility of proposed mitigation measures in reducing human health effects and whether a specific mitigation measure is expected to achieve the desired result. This information may be complementary to the applicable regulations or guidelines of other jurisdictions. Some provincial and/or municipal legislation or guidelines may not take into account all human health-related endpoints. Since Health Canada provides advice on human health endpoints that may exceed the requirements of other jurisdictions, it is advisable that the use of a provincial or other jurisdiction’s approach (if applicable) be clearly indicated to assist Health Canada’s review of EA documents. When federal, provincial, or territorial authorities require additional information or clarification concerning the assessment of noise effects (as detailed in Section 5 of this document) or specific information or advice related to any proposed assessment techniques, they are encouraged to contact Health Canada.

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Guidance for Evaluating Human Health Impacts in EA: Noise

5 HEALTH IMPACTS ASSOCIATED WITH NOISE CONSIDERED BY HEALTH CANADA IN ENVIRONMENTAL ASSESSMENTS Although many possible human health effects from noise exposure are plausible, Health Canada’s emphasis in the review of the EA is only on those endpoints that have demonstrated a reasonable causal relationship between adverse human health effects and noise exposure. The following sections provide an overview of the human health effects of noise. For further details concerning these effects and detailed definitions of technical terms, refer to Appendices A and C, respectively.

5.1 Noise-Induced Hearing Loss (NIHL) When the human ear is exposed to excessive sound levels over long periods of time, permanent damage may occur (WHO 1999). There is no known risk of hearing loss associated with sound levels below 70 dBA 1 regardless of the exposure duration. However, as sound levels increase, the duration of daily exposure becomes an important risk factor for hearing loss. If the 8-hour equivalent continuous sound levels (Leq 8) are 85 dBA or more, a significant risk of permanent hearing loss may occur (WHO 1999). When considering impulsive noise, Health Canada advises following the WHO recommendation to avoid hearing loss resulting from impulsive noise exposure and that peak sound pressures not exceed 140 dBZ 2.

5.2

Sleep Disturbance

Sleep disturbance includes the following effects of noise: difficulty falling asleep, awakenings, curtailed sleep duration, alterations of sleep stages or depth, and increased body movements during sleep. Health Canada advises that the recommendations and guidelines of the WHO (WHO 1999) regarding sleep disturbance be taken into consideration in the EA. In quiet rural areas and susceptible populations such as those in hospitals, or convalescent or senior homes, Health Canada suggests that the WHO guideline levels not be exceeded. The WHO’s Guidelines for Community Noise (1999) report a threshold for sleep disturbance of an indoor night-time sound level (Ln) of no more than 30 dBA for continuous noise. For individual noise events, the WHO has stated: “For a good sleep, it is believed that indoor sound pressure levels should not exceed approximately 45 dBA LA max 3 more than 10-15 times per night.”

1dBA - A weighting of the frequencies in a sound that approximates response of the human ear to frequencies in moderately loud sounds (sound pressure levels in the range of 45-65 dBA). 2 dBZ - A frequency weighting in which all measured frequencies in the range of 10 Hertz-20 Kilohertz are equally represented (± 1.5 dB). 3 LA max - The maximum A-weighted sound pressure level.

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Guidance for Evaluating Human Health Impacts in EA: Noise

Most studies show that an increase in the percentage of awakenings is expected to occur at indoor sound exposure level (SEL) values of 55-60 dBA (WHO 1999). Health Canada recognizes that in many cases, people will want to keep windows at least partially open depending on the season. Unless specified otherwise, it is assumed by Health Canada that an outdoor-to-indoor transmission loss with windows at least partially open is 15 dBA (EPA 1974, WHO 1999). Fully closed windows are assumed to reduce outdoor sound levels by approximately 27 dBA (EPA 1974). As a result, for an external continuous noise Ln at 45 dBA, or for intermittent noise with no more than 10-15 individual noise events not exceeding 60 dBA (LA max), the WHO sleep disturbance thresholds would not typically be exceeded for indoor receptors with windows partially open. Such estimates are useful to determine whether the WHO threshold for sleep disturbance would be exceeded. In addition to sleep disturbances occurring in homes, sleep disturbances experienced by off-duty workers who reside on or near a project site in worker camps may need to be considered. It is important to note that the percent highly annoyed (% HA) criteria discussed in Section 5.5, which is applicable to noise effects with a duration of greater than one year, are not applied to project workers residing onsite or in nearby worker’s camps. Health Canada advises that suitable noise protection measures be considered for off-duty workers to limit sleep disturbance and related human health impacts.

5.3 Interference with Speech Comprehension Health Canada advises that background indoor sound levels for continuous noise be maintained below 40 dBA to sustain adequate speech comprehension. This sound level is 15-18 dBA lower than normal indoor speaking levels, which are typically 55-58 dBA (Levitt and Webster 1991). For good outdoor speech comprehension, Health Canada advises that background outdoor noise levels be kept below 55 dBA for continuous noise (i.e. 60 dBA with a 5-dBA margin of safety). This level, obtained from EPA 1974, considers that 95% sentence intelligibility is acceptable in outdoor environments where distances of up to two metres exist between speakers. This level is also considered appropriate based on people’s tendency to speak in a louder voice when outdoors, where the separation between speakers is typically larger than indoors and where outdoor interferences such as wind, water and animal sounds may raise background noise levels to 50 dBA.

5.4 Complaints Many municipal policies concerning noise are based on the resolution of complaints. Reliance on noise complaints may only provide a partial indication of a noise problem. The likelihood of a complaint is directly linked to the ability or willingness of an individual to make a complaint and his or her expectation that the complaint will result in noise reduction (Michaud et al. 2008).

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Guidance for Evaluating Human Health Impacts in EA: Noise

Michaud et al. (2008) discussed the divergence between “sporadic complaints” and “widespread complaints” when the normalized Ldn 4 of the intruding noise (i.e. project noise) reached 62 dBA. Based on this work, Health Canada suggests that this level be used in considering effects related to widespread complaints. When project sound levels are greater than a normalized 75 dBA Ldn level, complaints can be expected to include several threats of legal action or strong appeals to authorities to stop noise.

5.5 High Annoyance When the human health effects cited above are considered separately, it may be difficult to quantify the impact of their combination in an EA, even for the average community. Therefore, high annoyance with noise is currently a reliable and widely accepted indicator of human health effects due to environmental noise (Michaud et al. 2008, Hanson et al. 2006, CSA 2005, ANSI 2005). As discussed in greater detail in this guidance, high annoyance is to be considered in addition to other potential noise-related human health endpoints (sleep disturbance, etc.). Annoyance, more specifically the change in percent highly annoyed (% HA) as a consequence of changing noise levels, is an endpoint that is not directly measured but self-reported in surveys. Although individual reaction varies greatly, the reported change in % HA among an average community in reaction to certain sound levels has been shown to be uniform (Michaud et al. 2008). The calculated % HA provides information on how an average community responds to a noise level. Health Canada considers the change in % HA as an appropriate indicator of noise-induced human health effects for project operational noise (see Section 6.3.2) and for long-term construction noise (see Section 0) exposure. Due to the non-linear nature of the relationship between noise and % HA, there can be a substantial increase in the % HA with relatively small changes in the noise environment in situations where the initial baseline noise level is high. In general, this relationship may be a useful tool in characterizing and quantifying the average community response to noise levels and changes in noise levels. Health Canada advises that high annoyance that is long-term (i.e. noise exposures greater than one year) be one of the human health effects considered in an EA. Health Canada advises that calculating the % HA be undertaken only for receptors that are exposed to longterm (i.e. greater than one year) project noise. In assessing the impacts of noise from projects using this endpoint, the project-related change in the sound environment and the related increase in % HA would be evaluated. In completing the assessment of increase in % HA, Health Canada advises that the increase in % HA per representative receptor (i.e. a group of residences in similar geographic proximity to the noise source) be evaluated and not the average increase in % HA for all receptors.

4

Ldn – normalized day - An equivalent continuous sound level taken over 24 hours with the night-time (10 p.m. to 7 a.m.) contributions adjusted (increased) by +10 dBA. Ldn may also be referenced as DNL.

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Guidance for Evaluating Human Health Impacts in EA: Noise

It should be noted that the change in % HA, when considered alone, will not necessarily be predictive of all noise-related human health effects when discrete noise events (momentary noise) occur in addition to sustained project-related long-term noise. This is due to the averaging that occurs in establishing an Ldn (or DNL) level when all noise is averaged over a 24-hour period. Discrete noise events that are momentary (i.e. train whistles) may last only several seconds and not contribute sufficient sound energy to the overall Ldn determination, thus having little impact on the calculation of % HA. When discrete noise events occur during periods in which long-term noise is evaluated, Health Canada advises using additional methodology described in this guidance (i.e. the evaluation of sleep disturbance) to evaluate human health impacts related to these discrete noise events. Health Canada advises that noise mitigation measures be considered when a change in the calculated % HA at any given receptor exceeds 6.5%. Appendix D presents the equations and methodology used for calculating % HA and outlines how this information could be presented in the EA. For additional information concerning % HA as a measure of community response to noise, refer to Michaud et al. 2008 and Hanson et al. (U.S. Federal Transit Authority 2006). It is important to note that the change in % HA is only one indicator of noise-related human health effects and that all possible human health endpoints be considered, particularly in situations where baseline noise levels are as high as DNL of 77 dBA or more and project noise levels by themselves exceed DNL of 75 dBA. Such combinations may make it too difficult to meet the advice proposed in Section 5.2 for vulnerable populations and sleep disturbance. It may also be too difficult to reduce these environmental noise levels to meet the advice suggested in Section 5.3 regarding adequate speech comprehension indoors for residents, in general. Therefore, Health Canada suggests that mitigation of project noise is advisable if it exceeds a DNL of 75 dBA. This advice is applicable even if the change in %HA does not exceed 6.5%. For example, if project noise alone exceeds a DNL of 75 dBA, it can be likely that the proposed levels in Section 5.2 and 5.3 are not achievable in typical residences even if windows are always kept closed and the windows and acoustic insulation provide the highest typical transmission loss available.

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Guidance for Evaluating Human Health Impacts in EA: Noise

6 SUGGESTED APPROACH FOR ASSESSING THE HEALTH IMPACTS OF NOISE The approach advised by Health Canada in noise assessment involves obtaining the best possible characterization of the acoustical exposure that may impact potential noise receptors. This includes noise characteristics such as sound level, duration, and other qualities such as whether the noise is tonal, impulsive, highly impulsive, etc. To obtain the highest quality data in acoustical studies, Health Canada advises that acoustical assessments be completed by professional and properly trained consultants using equipment and methods that are recognized as the industry standard for acoustical measurements. In some cases, limitations may exist in the technology and expertise available for some projects. Whenever uncertainty exists in the selection of appropriate monitoring equipment or in the application of standard techniques for noise characterization in EAs, federal, provincial or territorial authorities are encouraged to consult Health Canada for assistance or additional guidance.

6.1 Identification of Human Receptors in Project Areas Health Canada advises identifying and describing all existing and reasonably foreseeable human receptors in the area that may be influenced by project-related noise and providing confirmation that all such receptors have been identified in the EA. The characterization of potential receptors would typically include the distance to the project’s local study area (LSA) and regional study area (RSA) for each receptor, and a map illustrating estimated noise levels from the project at receptors in the study area. While sound levels at one receptor are typically averaged over time, it is not appropriate to assess noise impacts using the average sound level increase across receptor locations corresponding to multiple sound level ranges. Health Canada advises identifying and describing whether particular receptors may have a heightened sensitivity to noise exposure (schools, child care centres, hospitals, etc.). When receptors with heightened sensitivity are not present, it would be helpful if this was stated in the EA. A list of commonly encountered receptors and related characteristics is provided in Appendix E. When identifying receptor sites at which noise impacts will be assessed, Health Canada advises the following: • these sites be representative of potentially impacted receptors • if there are local receptors that may be influenced by project noise that are not being assessed, provide a justification as to why these receptors have been excluded in the EA • receptors that have rented dwellings or land be considered in the assessment • receptors that may be impacted by a project that live outside Canada be described where applicable. If no human receptors are present in the local or regional study area during the construction, operation or decommissioning phases of the project, no further assessment with respect to noise is necessary. While Health Canada does not provide advice on occupational exposure to noise, it is acknowledged that offduty workers who reside in worker camps or in nearby locations may be impacted by project noise as discussed in Section 5.2. These individuals may be viewed as temporary residential receptors; therefore, noise impacts on these receptors may be considered. Health Canada can provide advice, if requested, on potential noise impacts in this situation.

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Guidance for Evaluating Human Health Impacts in EA: Noise

Health Canada advises identifying and describing any receptors in rural areas that could be considered to have a greater expectation of “peace and quiet” (i.e. quiet rural areas). Health Canada considers a quiet rural area with day-night sound levels (Ldn) due to human-made sounds to be below 45 dBA. For areas with the most stringent permissible noise levels, provincial regulatory criteria may also be used to define “quiet rural areas” provided these areas are adequately described. Due to the expected heightened sensitivity to noise in quiet rural areas, Health Canada advises adjusting the predicted project noise and baseline levels by adding 10 dBA (CSA 2005, ANSI 2005) to the predicted project noise level for all phases of the project (i.e. construction, operation and decommissioning) in order to determine % HA as a human health endpoint. In more urbanized areas, this adjustment is not applied. The effect of this +10 dBA adjustment in quiet rural areas is to produce a greater change in % HA than would occur with unadjusted noise levels. The exponential relationship between % HA and noise levels, as discussed in Section 5.5, produces increasingly larger changes in % HA for equal increases in project noise compared to the baseline level as the noise levels increase. An example of this effect is provided below. When the initial baseline noise level is 45 dBA and the project-related noise level is 55 dBA, the unadjusted change in % HA would be 3.01 (based on Equation D5 in Appendix D). When the +10 dBA adjustment to both baseline and project-related noise is applied in a quiet rural area, the baseline rating level becomes 55 dBA and the project-related noise rating level becomes 65 dBA. At these rating levels, the resulting change in % HA is 9.79. As illustrated in the above example, a 10-dBA project-related noise increase from a baseline of 55 dBA will result in exceeding the mitigation level of 6.5% while a 10-dBA increase in project-related noise from a baseline of 45 dBA would not exceed this level.

6.2 Characterization of Baseline Sound Levels at Receptors Baseline noise levels, determined as described in this section, can be applied to noise impact assessments for the construction, operation and decommissioning project phases. Health Canada advises that measured or valid estimates of baseline noise levels for both daytime (Ld) and night-time (Ln) at the receptor locations be assessed and reported in the EA. Clarity as to whether sound levels are measured or estimated and the exact location of the baseline measurement (outdoors at the building facade, or on the lower level, upper level, property line, etc.) is advised.

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Guidance for Evaluating Human Health Impacts in EA: Noise

6.2.1

Baseline Noise Monitoring

To minimize uncertainty of the validity of the baseline monitoring sound level data, Health Canada advises that the EA report provides the following information: • the number of hours or days used for monitoring and a rationale explaining why the reported noise levels can be considered representative • an estimate of seasonal differences and any differences between the weekend and weekday baseline noise levels • where applicable, any differences due to weather conditions • all noise sources that contribute significantly to the baseline by type (traffic, aircraft, trains, industrial, etc.) • a characterization of each noise type described in the assessment using descriptors: continuous, intermittent, regular impulsive, highly impulsive, and high-energy impulsive, continuous tonal, intermittent tonal, etc. It is important to differentiate between construction and operational noise levels from baseline levels at each receptor as this will be reflective of the noise effects experienced by each receptor. When baseline monitoring is conducted, Health Canada advises that the monitoring be completed in accordance with ISO 1996-2 (2007) at each receptor and include the hours used to characterize these measurements. Sounds that are not generated by human activity (ocean, wind and animal noises, etc.) would not be included in determining a baseline noise level. Wind and rain can also create false signals in the microphone used to measure noise levels. As a result, noise is not measured in the presence of precipitation or when wind speeds exceed 14 km/hr unless an appropriate wind screen is used. This consideration is especially important in the context of wind turbine noise. 6.2.2

Baseline Noise Estimates

Though monitoring is considered the standard approach for baseline determinations, there may be situations where baseline monitoring data is not available. In such cases, Health Canada can provide specific advice and knowledge to ensure the accuracy and validity of baseline estimates on a case-by-case basis. Different approaches to baseline estimates are possible. One conservative (i.e. most protective) approach may be to consider a reasonable worst-case scenario and assume Ldn baselines of 35 dBA for rural areas and 45 dBA for urban/suburban areas. Defaulting to these lower baseline sound levels may result in greater values obtained for change in % HA when calculating noise effects for construction lasting more than one year or for operational noise. Note that the estimate of an Ldn of 45 dBA for urban/suburban areas does not consider the inherent variability in baseline noise estimates in suburban or urban areas based on population density, proximity to busy roads, or adjacent industrial activity. The use of alternate approaches may yield higher baseline estimates than the reasonable worst-case scenario described above. To adequately review the reliability of such estimates, Health Canada advises that sufficient supporting rationale for the baseline estimate approach selected is provided in the EA, particularly where the accuracy of the selected estimation approach decreases.

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Guidance for Evaluating Human Health Impacts in EA: Noise

Other approaches to estimating baseline noise in order of decreasing accuracy include the following: • predictions based on computer models whose inputs, algorithms and outputs are based on accepted standards • manual calculation procedures based on well-accepted models or standards • the use of known baseline levels from areas with very similar acoustical environments (i.e. very similar types of baseline noise sources, distances from sources to receptors, meteorological conditions, shielding, etc.) • approximate values from Table 6-1(See below.) Table 6-1 below is based on a qualitative description of community characteristics and an average census-based population density (EUB Directive 38, 2007). If this method (based on EPA 1974 and AERCB 2007) is used, Health Canada advises that a rationale be provided to support the validity of its use.

Table 6-1: Estimation of Baseline Noise Levels Using Qualitative Descriptions and Population Densities of Average Types of Communities

Community Type (Qualitative Description) Quiet rural area (dwelling units more than 500 m from heavily travelled roads and/or rail lines and not subject to frequent aircraft flyovers)

Average Census Tract Population Density, Number of People Per Square km (Mile)

28

(71)

Estimated Baseline Sound Level, 1 Ldn (dBA) ≤ 45

2

Quiet suburban residential community (remote from large cities, industrial activity and trucking)

249 (630)

48-52

Normal suburban residential community (not located near industrial activity)

791 (2000)

53-57

Urban residential community (not immediately adjacent to heavily travelled roads and industrial areas)

2493 (6300)

58-62

Noisy urban residential community (near relatively busy roads or industrial areas)

7913

(20,000)

63-67

Very noisy urban residential community

24,925 (63,000)

68-72

1- Note that a range of values are provided and that selection of the appropriate estimated value would typically be based on the precautionary principle in the absence of adequate justification for a higher baseline. All Ldn values, except that of the quiet rural area community type, are based on the U.S. EPA Levels document (EPA 1974). 2- The quiet rural area (Ln = 35 dBA) estimated baseline noise level and population density were obtained from EUB Directive 38 (revised Feb 16, 2007). The difference between Ld and Ln was obtained from EUB and EPA, and was approximated as 10 dBA. As such, quiet rural areas are considered to be less than or equal to 45 dBA Ldn.

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Guidance for Evaluating Human Health Impacts in EA: Noise

6.3 Noise Assessment Methods and Health Effects Health Canada advises that the criteria used to review the human health impacts of project-related noise be documented and that the potential for change in the sound environment due to any project activity (including construction, operation and decommissioning) be characterized. For changes in long-term noise levels, Appendix D describes the methodology and equations related to calculating the change in % HA, and provides a suggested format for presenting data and results. Health Canada suggests that the type of measurements used and the uncertainty associated with any sound monitoring, modelling or estimates be provided for all reported data. It is important to consider that human health effects related to noise may be evaluated by a variety of endpoints, as discussed in Section 5. Health Canada advises that the evaluation of each potential noise-induced human health effect as one method alone is not predictive of all possible human health effects related to noise exposure. For example, the change in % HA of receptors exposed to long-term noise may not exceed 6.5%, but these receptors may experience sleep disturbances due to an exceedance of the WHO sleep disturbance threshold limit discussed in Section 5.2. When changes in the sound environment have been characterized, Health Canada advises that a description of an evaluation of the severity of these changes and how they impact human health be included in the noise assessment. This evaluation would typically occur for all appropriate endpoints to address potential impacts on human health as described in this guidance. Alternative approaches to this evaluation may be acceptable provided they are supported by adequate scientific justification. In some cases, a less extensive assessment may be warranted. If noise levels at all receptors are not expected to approach the U.S. EPA’s levels (Table 6-3) or result in a change in % HA exceeding 6.5% as discussed in Section 5.5, Health Canada advises that a scientifically sound rationale be provided in the EA to confirm that noise levels will be well below the level where human health effects may occur and that this rationale has been provided in place of a complete noise impact assessment. When EAs under provincial or municipal jurisdiction are undertaken and human health endpoints are not an explicit part of the assessment, it may also be appropriate to consider the impacts of predicted project-induced changes in the sound environment on human health endpoints such as sleep disturbance, interference with speech comprehension and calculated increases in % HA. Generally, the results and conclusions of the noise assessment are to be clearly documented in the EA. Health Canada advises that the conclusion include a discussion of whether mitigation measures or follow-up monitoring is warranted. 6.3.1

Evaluation of Construction Noise

Noise from construction activities often has the potential to negatively impact nearby receptors and is often the loudest source of project-related noise.

14

Guidance for Evaluating Human Health Impacts in EA: Noise

The method for determining impacts related to construction noise is dependent on the duration of the construction activities. When construction duration is anticipated to be less than one year, Health Canada advises the use of the methods described in EPA (1974) discussed in Section 6.3.1.1 below. For construction projects that are expected to exceed one year, Health Canada advises that construction noise be evaluated as operational noise and that an assessment of the change in % HA at each receptor be considered for potential noise-related human health impacts in accordance with ISO 1996-1. There may be insufficient information concerning construction activities to permit an assessment of their impacts at the EA stage. Conservative assumptions based on similar projects and/or planned activities are often used in estimating noise levels and calculating impacts due to construction. An example of this estimation technique is to assume that all equipment is operating simultaneously for a 12-hour period even though actual impacts are expected to be lower. In these cases, Health Canada suggests providing as much information as possible on construction activities, schedules, equipment use and any assumptions used, in addition to an explanation of why a more detailed assessment is not possible. Health Canada suggests including a description of construction noise as it relates to exposure duration rather than construction activity duration. The difference in these perspectives becomes apparent when considering the impacts of construction noise related to road projects. As a road project progresses, noise exposure continually varies from receptor to receptor as the geographic location changes for the construction equipment. 6.3.1.1 Short-Term Construction Noise Exposure (12 Months) When construction activities are expected to last longer than 12 months, Health Canada advises that construction noise be treated as operational noise. This means that an evaluation of % HA at each receptor would be the most appropriate measure of potential noise-related human health impacts in accordance with ISO 1996-1. Appendix D describes the methodology and equations related to calculating the change in % HA for construction projects, and provide a suggested format for presenting this information. The specific adjustments that may be applied to the A-weighted calculated or measured noise Leq day (Ld) and Leq night (Ln) for both construction and operational noise are presented in the respective tables. This method of assessing construction noise is essentially identical to that of assessing operational noise as discussed in Section 6.3.2 below. 6.3.2

Assessment of Project Operation Noise

As discussed previously, Health Canada advises that the determination of % HA is a reliable and widely accepted indicator of the human health effects of long-term noise exposure. Health Canada also advises that information to be provided with respect to operational noise include the predicted daytime and night-time noise levels at all representative receptors. Finally, Health Canada advises that the units, averaging times and other measurement parameters, including the uncertainty associated with any of the measurements be the same as those used in establishing the baseline to permit a proper comparison. If project-related noise levels are given independently of baseline sound levels, Health Canada advises that this be clearly indicated. In assessing impacts on human health, the baseline and project noise are added together, as their sum represents what noise effects the receptors will actually experience. Other changes in the sound environment may also be characterized. If project-related operational noise includes audible tonal or impulsive noise (including regular impulsive, highly impulsive and high-energy impulsive types of noise (CSA 2005)) (e.g. blasting), appropriate adjustments as presented in Appendix D can be made. Please reference the ISO standard (Section 6.4 below) for additional guidance on describing or measuring tonal and impulsive noise. These adjustments apply only when the noise under consideration is audible at receptors. In situations where more than one source characteristic adjustment is applicable (e.g. impulsive or tonal), only the higher of the adjustments is used. However, all timeof-day adjustments and the quiet rural area adjustment are to be added to the highest of the applicable source adjustments. Modelling using appropriate software is one method that is commonly used to estimate present or future operational sound levels. Health Canada advises that the models used be documented and their suitability are appropriately justified. Specific models may be selected on a site-by-site basis. Health Canada advises that any assumptions used be conservative (i.e. reasonable worst-case scenario) and be adequately described in the assessment.

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Guidance for Evaluating Human Health Impacts in EA: Noise

6.4 Monitoring and Mitigation Noise management and noise monitoring plans, including complaint resolution, may be incorporated as required, as part of the Environmental Management Plan. 6.4.1

Monitoring

The periodic monitoring of sound levels at representative receptors can be used to verify predictions made during the EA process. This monitoring is particularly important when predicted noise levels approach the level where adverse human health effects are considered likely and mitigation measures become necessary. If the uncertainty related to predicted sound levels is large and the resulting impacts are more severe than expected, monitoring is considered particularly useful. Additionally, if potential human health impacts warrant, Health Canada advises the inclusion of a plan to manage and address noise complaints in the EA. Commitments to evaluate the need for additional mitigation measures may also be included in the EA if actual project-related noise levels are higher than predicted or if community reaction is stronger than expected. If post-project monitoring is not being undertaken when projected noise levels are close to the suggested mitigation measure levels, Health Canada advises providing a justification in the EA documentation explaining why monitoring is not required. 6.4.2

Mitigation

When project-related noise health effects are possible, Health Canada advises that a noise management plan detailing the actions that will be taken to minimize human health impacts due to project noise (mitigation measures) be developed and included in the EA. Health Canada advises that special consideration be given to mitigation measures for construction noise that occurs at night to minimize impacts on sleep (i.e. avoiding impulsive noise sources at night). Given that there are uncertainties in baseline monitoring and the predicted values of construction and operational noise, exceedances of the suggested MNLs and/or % HA are possible when the predicted values are close to the suggested mitigation levels. In such cases, it is advisable to provide additional information to demonstrate that exceedances are unlikely or consider proposing specific mitigation measures to limit noise at receptors where this uncertainty exists. Health Canada advises that any mitigation measures proposed for the project be described in sufficient detail to permit Health Canada to adequately review the measures’ impacts on achieving noise reduction. In describing possible mitigation or other noise management measures in the EA, identifying the conditions or circumstances under which various mitigation measures will be applied or implemented is advised. Health Canada advises that mitigation measures be applied to the source rather than the receptor where this is technically feasible. It should be noted that some estimates (i.e. noise attenuation by closed windows or enclosed balconies) discussed in Section 5.2 may not achieve the desired level of noise reduction due to variability in construction techniques. While fully closed windows are assumed to typically reduce outdoor sound levels by 27 dBA (EPA 1974), the type of enclosures that surround the windows or the presence of ventilation ducts may increase noise transmission into some buildings.

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Guidance for Evaluating Human Health Impacts in EA: Noise

6.4.2.1 Short-Term Construction ( one year) noise exposure considerations in EAs. It is important to emphasize that these annoyance responses are not applicable to a particular individual or group, but represent an average community. To assess the impacts of noise from development projects, the project-related change in the sound environment and the increase in % HA are evaluated. The ISO method does not characterize the nature of the increases in terms of severity of impact. However, the U.S. Federal Transit Administration describes a long-term increase of more than 6.5% HA as representing a severe project-related noise impact. This increase is based in part on the historical acceptability in the U.S. of no more than a 5-dBA increase in Ldn in an urban residential environment (not immediately adjacent to heavily travelled roads and industrial areas). Further justification for using an increase of 6.5% HA as a criterion for a severe noise-related impact may be found in Michaud et al. 2008 and Hanson et al. 2006. ISO 1996-1 notes that research has shown that there is a greater expectation for and value placed on “peace and quiet” in quiet rural areas. This expectation is assumed by Health Canada to be equivalent to an RL adjustment of up to 10 dBA.

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Guidance for Evaluating Human Health Impacts in EA: Noise

APPENDIX D METHODOLOGY (EQUATIONS AND FORMAT FOR DATA REPORTING) Introduction A format for the presentation of data associated with the calculation of % HA as a human health endpoint is provided below. As stated in Sections 0 and 6.3.2, this method of noise assessment is applicable only to construction projects lasting more than one year or to project operation. The assessment of noise using this method has been divided into various components, which contribute to the calculation of the final change in % HA. This format will assist in the evaluation of the overall energy-summed result of all adjusted noise inputs and will clarify the calculation methods necessary to obtain the final result. Baseline Noise Assessment The baseline assessment has been separated into daytime Table D1 a) and night-time Table D1 b) baseline evaluations. The baseline sound levels (noise) for both day and night are determined (measured, predicted or estimated as per Section 6.2) and the contributing noise sources are evaluated separately to permit the applicable noise adjustments to be made as detailed below. When a particular sound source or character is present, the applicable adjustment to this noise value is added to obtain the adjusted noise. It is important to consider that the various adjustments are obtained either directly from or based on either CAN/ISO ISO 1996-2:2003 (2005) or ANSI 2005 (ANSI S12.9-2005/Part 4. American National Standard Quantities and Procedures for Description and Measurement of Environmental Sound - Part 4: Noise Assessment and Prediction of Long-term Community Response) depending on the sound source or character adjustment. Please refer to Appendix A Glossaryfor various sound character definitions.

42

Guidance for Evaluating Human Health Impacts in EA: Noise

Table D1 a) Determination of Baseline Leq (Day 07:00 – 22:00) with Applicable Sound Source and Character Adjustments Sound Source Adjustments (Various Contributions) +

(07:0022:00)

Road Traffic (R) -

Noise Receptor

Noise (dBA)

Air Traffic (AT) Noise (dBA)

Adjusted Noise (+5dBA)

Rail Traffic (RT) * Noise (dBA)

Adjusted Noise (-5 dBA)

Industry (I) Noise (dBA)

Sound Character Adjustments (at noise receptor) +

Regular Impulsive (RI) Noise (dBA)

Adjusted Noise (+5 dBA)

Highly Impulsive (HI) Noise (dBA)

Adjusted Noise (+12 dBA)

High Energy Impulsive (HEI) Noise (dBC)

Adjusted Noise (dBC)

Prominent Tones (PT) Noise (dBA)

Adjusted Noise (+5 dBA)

Lowfrequency (LF) Noise (dBA)

Adjusted Noise■ (dBC)

Energy Summed Result of all Adjusted Noise Adjusted Baseline Leq (07:0022:00) (dB)

1 2 * Rail adjustment is not applicable to electric locomotives with 12 or more cars or to trains operating at speeds in excess of 250 km/hr or to diesel trains regardless of the number of cars or speed. - Sound source adjustments for road traffic and industry are 0 dBA and as such an additional column for Adjusted Noise is not provided in this table. ■ Sound character adjustments are obtained from ANSI (2005). Note: Where dBC – dBA >10 dB for essentially continuous noise, Health Canada advises the assessment of this low frequency noise as per ANSI (2005). + Health Canada advises that applicable baseline noise adjustments be made before calculating project noise plus baseline sound levels at each receptor. When adjustments to project noise are necessary, Health Canada advises adjustments be made by following CAN/CSA - ISO 1996 -1:05 (ISO 1996-1: 2003). For sources (AT, RT and for sound character PT) Health Canada advises specific adjustments that fall within the ranges given in CAN/CSA - ISO 1996 -1:05 (ISO 1996-1: 2003). For sound characters (RI, HI and HEI) Health Canada advises specific adjustments identical to those given in the ISO standard.

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Guidance for Evaluating Human Health Impacts in EA: Noise

Table D1 b) Determination of Baseline Leq (Night 22:00 – 07:00) with Applicable Sound Source and Character Adjustments Sound Source Adjustments (Various Contributions) +

(22:007:00)

Road Traffic (R) -

Noise Receptor

Noise (dBA)

Air Traffic (AT) Noise (dBA)

Adjusted Noise (+ 5dBA)

Rail Traffic (RT) * Noise (dBA)

Adjusted Noise (-5 dBA)

Industry (I) Noise (dBA)

Sound Character Adjustments (at noise receptor) +

Regular Impulsive (RI)

Highly Impulsive (HI)

High Energy Impulsive (HEI)

Noise (dBA)

Noise (dBA)

Noise (dBC)

Adjusted Noise (+5 dBA)

Adjusted Noise (+12 dBA)

Adjusted Noise (dBC)

Prominent Tones (PT) Noise (dBA)

Adjusted Noise (+5 dBA)

Lowfrequency (LF) Noise (dBA)

Adjusted Noise■ (dBC)

Energy Summed Result of all Adjusted Noise Adjusted Baseline Leq (22:0007:00) (dB)

1 2 * Rail adjustment is not applicable to electric locomotives with 12 or more cars or to trains operating at speeds in excess of 250 km/hr or to diesel trains regardless of the number of cars or speed. - Sound source adjustments for road traffic and industry are 0 dBA and as such an additional column for Adjusted Noise is not provided in this table. ■ Sound character adjustments are obtained from ANSI (2005). Note: Where dBC – dBA >10 dB for essentially continuous noise, Health Canada advises the assessment of this low frequency noise as per ANSI (2005). + Health Canada advises that applicable baseline noise adjustments be made before calculating project noise plus baseline sound levels at each receptor. When adjustments to project noise are necessary, Health Canada advises adjustments be made by following CAN/CSA - ISO 1996 -1:05 (ISO 1996-1: 2003). For sources (AT, RT and for sound character PT) Health Canada advises specific adjustments that fall within the ranges given in CAN/CSA - ISO 1996 -1:05 (ISO 1996-1: 2003). For sound characters (RI, HI and HEI) Health Canada advises specific adjustments identical to those given in the ISO standard.

44

Guidance for Evaluating Human Health Impacts in EA: Noise

Calculation of Adjusted Baseline Leq (Day) or Leq (Night) Once the applicable sound source and character adjustments have been applied, the respective adjusted sound energies are added according to Equation D1 and the resultant adjusted baseline Leq is obtained. Adjusted Baseline Leq = 10 log 10 [10(0.1 x R) + 10(0.1 x AT) + 10(0.1 x RT) + 10(0.1 x I) + 10(0.1 x RI) + 10(0.1 x HI) + 10(0.1 x HEI) + 10(0.1 x PT) + 10(0.1 x LF)]

(D1)

Note: When a particular sound source is not present (e.g. air traffic (AT)), the applicable term in Equation D1 (i.e. 10(0.1 x AT)) reduces to zero and does not contribute to the sound energy sum. The values obtained for both the day and night adjusted baseline Leq are inserted into Table D1 g) (Construction) or D1 h) (Operation) for further calculation. Determination of Construction Noise Construction noise assessments have been separated into daytime (Table D1 c)) and night-time (Table D1 d)). The construction noise levels for both day and night are determined and the contributing noise sources are evaluated separately to permit the applicable noise adjustments to be made as detailed in the following tables:

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Guidance for Evaluating Human Health Impacts in EA: Noise

Table D1 c) Determination of Construction Leq (Day 07:00 – 22:00) with Applicable Sound Source and Character Adjustments Sound Source Adjustments (Various Contributions) +

(07:0022:00)

Road Traffic (R) -

Noise Receptor

Noise (dBA)

Air Traffic (AT) Noise (dBA)

Adjusted Noise (+ 5dBA)

Rail Traffic (RT) * Noise (dBA)

Adjusted Noise (-5 dBA)

Industry (I) Noise (dBA)

Sound Character Adjustments (at noise receptor) +

Regular Impulsive (RI) Noise (dBA)

Adjusted Noise (+5 dBA)

Highly Impulsive (HI) Noise (dBA)

Adjusted Noise (+12 dBA)

High Energy Impulsive (HEI) Noise (dBC)

Adjusted Noise (dBC)

Prominent Tones (PT) Noise (dBA)

Adjusted Noise (+5 dBA)

Lowfrequency (LF) Noise (dBA)

Adjusted Noise■ (dBC)

Energy Summed Result of all Adjusted Noise Adjusted Construction Leq (07:0022:00) (dB)

1 2 * Rail adjustment is not applicable to electric locomotives with 12 or more cars or to trains operating at speeds in excess of 250 km/hr or to diesel trains regardless of the number of cars or speed. - Sound source adjustments for road traffic and industry are 0 dBA and as such an additional column for Adjusted Noise is not provided in this table. ■ Sound character adjustments are obtained from ANSI (2005). Note: Where dBC – dBA >10 dB for essentially continuous noise, Health Canada advises the assessment of this low frequency noise as per ANSI (2005). + Health Canada advises that applicable baseline noise adjustments be made before calculating project noise plus baseline sound levels at each receptor. When adjustments to project noise are necessary, Health Canada advises adjustments be made by following CAN/CSA - ISO 1996 -1:05 (ISO 1996-1: 2003). For sources (AT, RT and for sound character PT) Health Canada advises specific adjustments that fall within the ranges given in CAN/CSA - ISO 1996 -1:05 (ISO 1996-1: 2003). For sound characters (RI, HI and HEI) Health Canada advises specific adjustments identical to those given in the ISO standard.

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Guidance for Evaluating Human Health Impacts in EA: Noise

Table D1 d) Determination of Construction Leq (Night 22:00 – 07:00) with Applicable Sound Source and Character Adjustments Sound Source Adjustments (Various Contributions) +

(07:0022:00)

Road Traffic (R) -

Noise Receptor

Noise (dBA)

Sound Character Adjustments (at noise receptor) +

High Energy Impulsive Air Traffic (AT) Noise (dBA)

Adjusted Noise + 5dBA

Rail Traffic (RT) * Noise (dBA)

Adjusted Noise (-5 dBA)

Industry (I) Noise (dBA)

Regular Impulsive (RI) Noise (dBA)

Adjusted Noise (+5 dBA)

Highly Impulsive (HI) Noise (dBA)

Adjusted Noise (+12 dBA)

(HEI) Noise (dBC)

Adjusted Noise (dBC)

Prominent Tones (PT) Noise (dBA)

Adjusted Noise (+5 dBA)

Lowfrequency (LF) Noise (dBA)

Adjusted Noise■ (dBC)

Energy Summed Result of all Adjusted Noise Adjusted Construction L eq (07:0022:00) (dB)

1 2 * Rail adjustment is not applicable to electric locomotives with 12 or more cars or to trains operating at speeds in excess of 250 km/hr or to diesel trains regardless of the number of cars or speed. - Sound source adjustments for road traffic and industry are 0 dBA and as such an additional column for Adjusted Noise is not provided in this table. ■ Sound character adjustments are obtained from ANSI (2005). Note: Where dBC – dBA >10 dB for essentially continuous noise, Health Canada advises the assessment of this low frequency noise as per ANSI (2005). + Health Canada advises that applicable baseline noise adjustments be made before calculating project noise plus baseline sound levels at each receptor. When adjustments to project noise are necessary, Health Canada advises adjustments be made by following CAN/CSA - ISO 1996 -1:05 (ISO 1996-1: 2003). For sources (AT, RT and for sound character PT) Health Canada advises specific adjustments that fall within the ranges given in CAN/CSA - ISO 1996 -1:05 (ISO 1996-1: 2003). For sound characters (RI, HI and HEI) Health Canada advises specific adjustments identical to those given in the ISO standard.

The calculation of adjusted construction Leq (day) or Leq (night) from tables D1 c) and D1 d) follows the same calculation method used for baseline assessment. The adjusted construction Leq values are inserted into Table D1 g) for further calculation.

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Guidance for Evaluating Human Health Impacts in EA: Noise

Determination of Operational Noise Operational noise assessments have been separated into daytime (Table D1 e)) and night-time (Table D1 f)). The operational noise for both day and night are measured or estimated and the contributing noise sources are evaluated separately to permit the applicable noise adjustments to be made as detailed in the following tables: Table D1 e) Determination of Operational Leq (Day 07:00 – 22:00) with Applicable Sound Source and Character Adjustments Sound Source Adjustments (Various Contributions) +

(07:0022:00)

Road Traffic (R) -

Noise Receptor

Noise (dBA)

Sound Character Adjustments (at noise receptor) +

High Energy Impulsive Air Traffic (AT) Noise (dBA)

Adjusted Noise (+ 5dBA)

Rail Traffic (RT)* Noise (dBA)

Adjusted Noise (-5 dBA)

Industry (I) Noise (dBA)

Regular Impulsive (RI)

Highly Impulsive (HI)

Noise (dBA)

Noise (dBA)

Adjusted Noise (+5 dBA)

Adjusted Noise (+12 dBA)

Prominent Tones (PT)

(HEI) Noise (dBC)

Adjusted Noise (dBC)

Noise (dBA)

Adjusted Noise (+5 dBA)

Low- frequency (LF) Noise (dBA)

Adjusted Noise■ (dBC)

Energy Summed Result of all Adjusted Noise Adjusted Operational Leq (07:0022:00) (dB)

1 2 * Rail adjustment is not applicable to electric locomotives with 12 or more cars or to trains operating at speeds in excess of 250 km/hr or to diesel trains regardless of the number of cars or speed. - Sound source adjustments for road traffic and industry are 0 dBA and as such an additional column for Adjusted Noise is not provided in this table. ■ Sound character adjustments are obtained from ANSI (2005). Note: Where dBC – dBA >10 dB for essentially continuous noise, Health Canada advises the assessment of this low frequency noise as per ANSI (2005). + Health Canada advises that applicable baseline noise adjustments be made before calculating project noise plus baseline sound levels at each receptor. When adjustments to project noise are necessary, Health Canada advises adjustments be made by following CAN/CSA - ISO 1996 -1:05 (ISO 1996-1: 2003). For sources (AT, RT and for sound character PT) Health Canada advises specific adjustments that fall within the ranges given in CAN/CSA - ISO 1996 -1:05 (ISO 1996-1: 2003). For sound characters (RI, HI and HEI) Health Canada advises specific adjustments identical to those given in the ISO standard.

48

Guidance for Evaluating Human Health Impacts in EA: Noise

Table D1 f) Determination of Operational Leq (Night 22:00 – 07:00) with Applicable Sound Source and Character Adjustments Sound Source Adjustments (Various Contributions) +

(07:0022:00)

Road Traffic (R)-

Noise Receptor

Noise (dBA)

Air Traffic (AT) Noise (dBA)

Adjusted Noise (+ 5dBA)

Rail Traffic (RT)* Noise (dBA)

Adjusted Noise (-5 dBA)

Industry (I) Noise (dBA)

Sound Character Adjustments (at noise receptor) +

Regular Impulsive (RI) Noise (dBA)

Adjusted Noise (+5 dBA)

Highly Impulsive (HI) Noise (dBA)

Adjusted Noise (+12 dBA)

High Energy Impulsive (HEI) Noise (dBC)

Adjusted Noise (dBC)

Prominent Tones (PT) Noise (dBA)

Adjusted Noise (+5 dBA)

Lowfrequency (LF) Noise (dBA)

Adjusted Noise■ (dBC)

Energy Summed Result of all Adjusted Noise Adjusted Operational Leq (22:0007:00) (dB)

1 2 * Rail adjustment is not applicable to electric locomotives with 12 or more cars or to trains operating at speeds in excess of 250 km/hr or to diesel trains regardless of the number of cars or speed. - Sound source adjustments for road traffic and industry are 0 dBA and as such an additional column for Adjusted Noise is not provided in this table. ■ Sound character adjustments are obtained from ANSI (2005). Note: Where dBC – dBA >10 dB for essentially continuous noise, Health Canada advises the assessment of this low frequency noise as per ANSI (2005). + Health Canada advises that applicable baseline noise adjustments be made before calculating project noise plus baseline sound levels at each receptor. When adjustments to project noise are necessary, Health Canada advises adjustments be made by following CAN/CSA - ISO 1996 -1:05 (ISO 1996-1: 2003). For sources (AT, RT and for sound character PT) Health Canada advises specific adjustments that fall within the ranges given in CAN/CSA - ISO 1996 -1:05 (ISO 1996-1: 2003). For sound characters (RI, HI and HEI) Health Canada advises specific adjustments identical to those given in the ISO standard.

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Guidance for Evaluating Human Health Impacts in EA: Noise

The calculation of adjusted operational Leq (day) and Leq (night) from tables D1 e) and D1 f) follow the same calculation method used for the baseline assessment. The adjusted operational Leq values are inserted into Table D1 h) for further calculation. Calculation of % HA (Construction) The Leq values obtained from the preceding tables are substituted into Table D1 g) below to obtain the values for % HA for construction. Table D1 g) Summary Table of Calculated Impact from Project Construction Noise (after all noise mitigation strategies are in place) on Magnitude of Community Reaction or Percentage Change in High Annoyance at Each Representative Noise Receptor Noise Receptor

Adjusted Baseline Leq (07002200) (dB) (Ld)

Adjusted Baseline Leq (22000700) (dB) (Ln)

Adjusted Baseline Ldn (dB)

Quiet Rural Area (y/n) 1

Adjusted Baseline Ldn (RL) 2 (dB)

% HA Baseline (Eqn. D5)

Adjusted Const. Leq (07002200) (dB) (Ld)

Adjusted Const. Leq (22000700) (dB) (Ln)

Adjusted Const. Ldn 2 (dB)

Adjusted Const. Ldn (RL) 2 (dB)

Adjusted Const. (RL) + Baseline (RL) (Eqn D4)

% HA Const. + Baseline (Eqn D5)

% HA Const. + Baseline minus % HA Baseline

Exceeds 6.5% increase in % HA (y/n)

1 2 1. A quiet rural area is considered an area where a noise receptor (or group of receptors) has a greater expectation for and value placed on “peace and quiet”. Before calculating project operation noise impacts on human health endpoints for receptors, Health Canada advises that baseline DNL be increased by 10 dBA for each applicable receptor when exposure duration is greater than one year. In the absence of further information, Health Canada will assume that receptors with a LAeq (0700-2200) of 45 dBA or less and a LAeq (2200-0700) of 35 dBA or less are quiet rural areas. 2. The only adjustment applicable in determining the adjusted baseline Ldn (RL) and adjusted operation Ldn (RL) is the quiet rural area adjustment. When receptors are identified as living in a quiet rural area, 10 dBA is added to both the adjusted baseline Ldn and the adjusted construction Ldn to obtain the adjusted baseline Ldn (RL) and adjusted operation Ldn (RL). Note: the addition of 10 dBA in this case is a linear sum (i.e. an adjusted baseline Ldn of 50 dBA becomes 60 dBA in a quiet rural area).

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Guidance for Evaluating Human Health Impacts in EA: Noise

Calculation Methods for Adjusted Baseline and Adjusted Construction Ldn The adjusted baseline Ldn is a 24-hour average in which the contribution from night-time events is artificially increased by 10 dB and is calculated using Equation D2. Adjusted Baseline Ldn = 10 log 10 [((15 x 10(0.1 x Adjusted Baseline Ld)) + (9 x 10(0.1 x (Adjusted Baseline Ln +10))) / 24]

(D2)

The adjusted construction Ldn is obtained from Equation D3. Adjusted Construction Ldn = 10 log 10 [((15 x 10(0.1 x Adjusted Construction Ld)) + (9 x 10(0.1 x (Adjusted Construction Ln +10))) / 24]

(D3)

The adjusted construction RL + baseline RL is defined by Equation D4. Adjusted Construction (RL) + Baseline (RL) = 10 log 10 (10(0.1 x Adjusted Construction RL) + 10 (0.1 x Baseline RL))

(D4)

The % HA baseline and % HA (construction + baseline) are obtained by substituting the adjusted baseline (RL) and adjusted construction (RL) + baseline (RL) respectively into Equation D5. % HA = 100 / [1+e (10.4 - 0.132 * RL)]

(D5)

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Guidance for Evaluating Human Health Impacts in EA: Noise

Calculation of % HA (Operation) The Leq values obtained from the preceding tables are substituted into Table D1 h) below to obtain the values for % HA for operation. Table D1 h) Summary Table of Calculated Impact from Project Operation Noise (after all noise mitigation strategies are in place) on Magnitude of Community Reaction or Percentage Change in High Annoyance at Each Representative Noise Receptor Noise Receptor

Adjusted Baseline Leq (07002200) (dB) (Ld)

Adjusted Baseline Leq (22000700) (dB) (Ln)

Adjusted Baseline Ldn (dB)

Quiet Rural Area (y/n) 1

Adjusted Baseline Ldn (RL) (dB) 2

% HA Baseline (Eqn D5)

Adjusted Operation Leq (07002200) (dB) (Ld)

Adjusted Operation Leq (22000700) (dB) (Ln)

Adjusted Operation Ldn (dB) 2

Adjusted Operation Ldn (RL) (dB) 2

Adjusted Operation (RL) + Baseline (RL) (Eqn D6)

% HA Operation + Baseline (Eqn D5)

% HA Operation + Baseline minus % HA Baseline

Exceeds 6.5% increase in % HA (y/n)

1 2

1. A quiet rural area is considered an area where a noise receptor (or group of receptors) has a greater expectation for and value placed on “peace and quiet”. Before calculating project operation noise impacts on human health endpoints for receptors, Health Canada advises that baseline DNL be increased by 10 dBA for each applicable receptor when exposure duration is greater than one year. In the absence of further information, Health Canada will assume that receptors with a LAeq (0700-2200) of 45 dBA or less and a LAeq (2200-0700) of 35 dBA or less are quiet rural areas. 2. The only adjustment applicable in determining the adjusted baseline Ldn (RL) and adjusted operation Ldn (RL) is the quiet rural area adjustment. When receptors are identified as living in a quiet rural area, 10 dBA is added to both the adjusted baseline Ldn and the adjusted construction Ldn to obtain the adjusted baseline Ldn (RL) and adjusted operation Ldn (RL). Note: the addition of 10 dBA in this case is a linear sum (i.e. an adjusted baseline Ldn of 50 dBA becomes 60 dBA in a quiet rural area).

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Guidance for Evaluating Human Health Impacts in EA: Noise

Calculation Methods for Adjusted Baseline and Adjusted Operation Ldn The calculation methods described previously for construction are applicable to operational noise assessments. The adjusted operation RL + baseline RL is defined by Equation D6. Adjusted Operation (RL) + Baseline (RL) = 10 log 10 (10(0.1 x Adjusted Operation RL) + 10 (0.1 x Baseline RL))

(D6)

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Guidance for Evaluating Human Health Impacts in EA: Noise

APPENDIX E IDENTIFICATION AND CHARACTERIZATION OF SOME COMMON RECEPTORS Receptor

Characterization

Comments/Considerations

Commercial premises

Retail stores, research facilities, and laboratories.

Noise effects during business hours.

Worker’s living quarters

Locations may be on or off the project site.

Mitigation measures in the design of temporary living quarters for workers to limit noise.

Entertainment establishments

Film and television studios, theatres, restaurants, etc.

Noise effects during periods of operation.

Permanent residences

Urban, suburban and rural locations containing houses, mobile homes and/or multilevel dwellings.

Noise effects over a 24-hour period with particular emphasis on night-time noise levels.

Seasonal residences Active recreation areas

Cottages, campgrounds and RV parks.

Noise effects considered during occupied periods.

Parks and sports grounds.

Noise effects considered during occupied periods.

Passive recreation areas

Outdoor grounds used for hunting, fishing, teaching, etc.

Noise effects considered during occupied periods.

Places of worship and cemeteries

Churches, mosques, synagogues, temples, locations where socially significant First Nations cultural or religious ceremonies occur, etc.

Noise effects during religious services, meetings or processions.

Schools

Education facilities from pre-school to universities.

Noise effects during regular hours of operation, which may include evenings and the possibility of schools being used during summer.

Highly sensitive receptor Hospitals

Highly sensitive receptor

Noise effects over a 24-hour period.

Daycare centres

Highly sensitive receptor

Noise effects considered during occupied periods.

Seniors residences

Highly sensitive receptor

Consideration of noise effects over a 24-hour period with particular emphasis on night-time noise levels.

Industrial premises

Factories and other large industrial plants.

Potential for additive noise in cumulative effects assessment.

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Guidance for Evaluating Human Health Impacts in EA: Noise

APPENDIX F COMMONLY APPLIED CONSTRUCTION NOISE MITIGATION MEASURES AND CONSIDERATIONS FOR NOISE REDUCTION The measures below have been adapted from the New South Wales Construction Noise Guideline (August 2008 draft for consultation), Department of Environment and Climate Change, New South Wales, Australia. General Mitigation Measures • Regularly train workers and contractors (such as at toolbox talks) to use equipment in ways that minimize noise. • Ensure that site managers periodically check the site, nearby residences and other sensitive receptors for noise problems so that solutions can be quickly applied. • Include in tenders, employment contracts, subcontractor agreements and work method statements clauses that assure the minimization of noise and compliance with directions from management to minimize noise. • Avoid the use of radios and stereos outdoors and the overuse of public address systems where neighbours can be affected. • Avoid shouting, and minimize talking loudly and slamming vehicle doors. • Keep truck drivers informed of designated vehicle routes, parking locations, acceptable delivery hours and other relevant practices (e.g. minimizing the use of engine brakes and periods of engine idling). Night-time Mitigation Measures • Avoid the use of equipment that generates impulsive noise. • Minimize the need for reversing alarms. • Avoid dropping materials from a height. • Avoid metal-to-metal contact on equipment. • If possible, schedule truck movements to avoid residential streets. • Avoid mobile plant clustering near residences and other sensitive receptors. • Ensure that periods of respite are provided in the case of unavoidable maximum noise level events. Consultation and Notification The community is more likely to be understanding and accepting of project noise if related information is provided and is frank, and does not attempt to understate the likely noise level, and if commitments are respected.

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Guidance for Evaluating Human Health Impacts in EA: Noise

Notification Before and During Construction Provide advance notification to people concerning construction duration, defining activities that are expected to be noisy and their expected duration, what noise mitigation measures are being applied, and when noise respite periods will occur. For night-time work, receptors may be informed in two stages: two weeks prior to construction and then two days before commencement. Provide information to neighbours before and during construction through media such as letterbox drops, meetings or individual consultation. In some areas, the need to provide notification in languages other than English may be considered. A Web site may also be established for the project. Use a site information board at the front of the site with contact details, hours of operation and regular information updates. Facilitate contact with people to ensure that everyone can see that the site manager understands potential issues, that a planned approach is in place, and that there is an ongoing commitment to minimize noise. Plant and Equipment In terms of both cost and results, controlling noise at the source is one of the most effective methods of minimizing the noise impacts from any construction activities. Quieter Methods Examine and implement, where feasible and reasonable, alternatives to rock-breaking work methods such as hydraulic splitters for rock and concrete, hydraulic jaw crushers, chemical rock and concrete splitting, and controlled blasting such as penetrating cone fracture. Consider alternatives to diesel and gasoline engines and pneumatic units such as hydraulic or electriccontrolled units where feasible and reasonable. When there is no electricity supply, consider using an electrical generator located away from residences. Examine and implement, where feasible and reasonable, alternatives to transporting excavated material from underground tunnelling off-site at night-time. (i.e. stockpile material in an acoustically treated shed during the night and load out the following day). Quieter Equipment Examine different types of machines that perform the same function and compare the noise level data to select the least noisy machine (i.e. rubber-wheeled tractors can be less noisy than steel-tracked tractors). Pneumatic equipment is traditionally a problem. Consider selecting super-silenced compressors, silenced jackhammers and damped bits where possible.

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Guidance for Evaluating Human Health Impacts in EA: Noise

When renting (or purchasing) equipment, select quieter pieces of plant and construction equipment where feasible and reasonable. As well, select the most effective mufflers, enclosures and low noise tool bits and blades. Always seek the manufacturer’s advice before making modifications to any equipment to reduce noise. Reduce throttle settings and turn off equipment when it is not being used. Examine and consider implementing, where feasible and reasonable, the option of reducing noise from metal chutes and bins by placing damping material in the bin. Equipment Maintenance Regularly inspect and maintain equipment to ensure that it is in good working order, including the condition of mufflers. For machines with enclosures, verify that doors and door seals are in good working order and that the doors close properly against the seals. Return any leased equipment that is causing noise that is not typical for the equipment. The increased noise may indicate the need for repair. Ensure that air lines on pneumatic equipment do not leak. Site Mitigation Measures Barriers and acoustic sheds are most suited to long-term fixed works as in these cases, the associated cost is typically outweighed by the overall time savings. Plant Location Place as much distance as possible between the plant or equipment and residences and other sensitive receptors. Restrict areas in which mobile plants can operate so that they are away from residences and other sensitive receptors at particular times. Locate site vehicle entrances away from residences and other sensitive receptors. Carry out noisy fabrication work at another site (e.g. within enclosed factory premises) and then transport products to the project site. Alternatives to Reversing Alarms Avoid the use of reversing alarms by designing the site layout to avoid reversing, such as by including drivethrough for parking and deliveries.

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Guidance for Evaluating Human Health Impacts in EA: Noise

When applicable legislation permits, consider less annoying alternatives to the typical ‘beeper’ alarms. Examples include smart alarms that are adjustable in volume depending on the ambient level of noise, and multi-frequency alarms that emit noise over a wide range of frequencies. Maximize Shielding Re-use existing structures rather than demolishing and reconstructing. Use full enclosures, such as large sheds, with good seals fitted to doors to control noise from night-time work. Use temporary site buildings and material stockpiles as noise barriers. Schedule the construction of permanent walls so that they can be used as noise barriers as early as possible. Use natural landform as a noise barrier. Place fixed equipment in cuttings or behind earth berms. Take note of large reflecting surfaces on- and off-site that might increase noise levels, and avoid placing noiseproducing equipment in locations where reflected noise will increase noise exposure or reduce the effectiveness of mitigation measures. Work Scheduling Schedule noisy work during periods when people are least affected. Provide Respite Periods Consult with schools to ensure that noise-generating construction works in the vicinity are not scheduled to occur during examination periods, unless other acceptable arrangements (such as relocation) can be made. When night work near residences cannot be feasibly or reasonably avoided, restrict the number of nights per week and/or per calendar month that the work is undertaken. Schedule Activities to Minimize Noise Impacts Organize work to be undertaken during the recommended standard hours where possible. If the construction site is in the vicinity of a sports venue, consider scheduling work to avoid times when there are special events. When work outside the recommended standard hours is planned, avoid scheduling it on Sundays or public holidays. Schedule work when neighbours are not present (e.g. commercial neighbours, college students and school students may not be present outside business hours or on weekends).

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Guidance for Evaluating Human Health Impacts in EA: Noise

Schedule noisy activities around times of high background noise (i.e. when local road traffic or other local noise sources are active) where possible to provide masking or to reduce the amount that the construction noise intrudes above the background noise. Deliveries and Access Nominate an off-site truck parking area away from residences for trucks arriving prior to gates opening and schedule deliveries only during specified periods. Optimize the number of vehicle trips to and from the site. Movements can be organized to amalgamate loads rather than using a number of vehicles with smaller loads. Designate access routes to the site through consultation with potentially noise-affected residences and other sensitive receptors, and inform drivers of nominated vehicle routes. Provide on-site parking for staff and on-site truck waiting areas away from residences and other sensitive receptors. Truck waiting areas may require walls or other barriers to minimize noise. Noise Transmission Path Physical methods to reduce the transmission of noise between construction locations and residences or other sensitive receptors are generally suited to construction projects in which there is long-term noise exposure. Reduce the line-of-sight noise transmission to residences and other sensitive receptors using temporary noise barriers. Temporary noise barriers can be constructed from boarding (plywood boards, panels of steel sheeting or compressed fibre cement board) with no gaps between the panels at the site boundary. Stockpiles and shipping containers can be effective noise barriers. Erect temporary noise barriers before work commences to reduce noise from construction as soon as possible. Where high-rise dwellings adjoin the construction site, the height of a barrier may not be sufficient to effectively shield the upper levels of the residential building from construction noise. Find out whether this is a consideration for the project and examine alternative mitigation measures where needed.

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