Indoor Air Pollution Monitoring Guidelines (Draft for comments)
CENTRAL POLLUTION CONTROL BOARD MINISTRY OF ENVIRONMENT & FORESTS, GOVT. OF INDIA EAST ARJUN NAGAR, DELHI 110 032 INDIA [email protected]
The Team Concept Dr. D. Saha
CPCB Technical Review
Sh. J. S. Kamyotra
CPCB IAQ Task Force
Prof. Mukesh Khare
Dr. D. Saha
Dr. Radha Goyal
University of Delhi
Consultative Prof. Ajay Taneja
Dr. BRA University, Agra
Ms. Shaveta Kohli
Sh. R. N. Jindal
Sh. A. Pathak
CPCB, Delhi Coordination
Dr. D. Saha
Monitoring Protocol for Indoor Air Quality Introduction The number of measurements in indoor atmospheric environment is increasing due to growing number of complaints about the indoor air quality (IAQ). In the past, many such measurements are performed by researchers to test the postulated hypothesis about the effects between the complaints and the sources. The respective buildings generally characterized as ‘sick building’ and the associated illnesses are classified under ‘sick building syndromes’. The causes of the complaints may be manifold that may include technical, chemical, physical, medical, psychological, sociological and economic factors. Correspondingly, the investigation strategies in ‘sick buildings’ must also be multi-interdisciplinary (Molhave, 1986). The successful investigation depends upon the efficient coordination between various experts in such multi-factorial relations. In order to coordinate such co-operation a protocol covering sampling, analyses, prediction and evaluation become an essential tool. However, this protocol must also define the specific ‘goals’ and specify as to they are achieved in such multi-factorial environment. The multi-factorial team may consists of experts like, building managers, heating, ventilation, and air conditioning (HVAC) engineers, and those performing the sampling and analyses (e.g. analyst), and those making predictions of IAQ (e.g. the IAQ modelers) and lastly those making the evaluation of the building and taking decisions (e.g. the controlling authority). Besides, the protocol must further ensure proper collection and recording of all information needed for the specific goals. Indoor air quality (IAQ) refers to the quality of the air inside buildings as represented by concentrations of pollutants and thermal (temperature and relative humidity) conditions that affect the health and performance of occupants. The growing proliferation of chemical pollutants in consumer and commercial products, the tendency toward tighter building envelopes and reduced ventilation to save energy, and pressures to defer maintenance and other building services to reduce costs have fostered IAQ problems in most of the buildings. As a result, occupant’s complaints of stale and stuffy air, and symptoms of illness or discomfort breed undesirable conflicts among occupants/owners/tenants/building managers. Therefore, it has become one of the most important issues of environment and health worldwide considering the principle of human rights to health that everyone has the right to breathe healthy indoor air. To solve the problems related to IAQ, a steering committee of experts are required to provide their opinions on the design, planning and implementation of IAQ measurement and control programs. The experts need to identify the key parameters that should be measured indoor in different types of buildings depending upon their use i.e. commercial, residential or sensitive (the sensitive buildings are classified as hospitals, schools, and old age homes etc. where sensitive receptors like women, children and old age people are occupants).
Causes of Indoor Air Pollution
Inadequate ventilation - increases indoor pollutant levels by not bringing in enough outdoor air to dilute emissions from indoor sources and by not carrying indoor air pollutants out of the home. High temperature and humidity levels - increase concentrations of some pollutants. There are many sources of indoor air pollution in any home. These include combustion sources such as oil, gas, kerosene, coal, wood, and tobacco products; building materials and furnishings as diverse as deteriorated, asbestos-containing insulation, wet or damp carpet, and cabinetry or furniture made of certain pressed wood products; products for household cleaning and maintenance, personal care, or hobbies; cooling systems and humidification devices; and outdoor sources such as radon, pesticides, and outdoor air pollution. Outdoor air enters and leaves a house by: infiltration, natural ventilation, and mechanical ventilation. In a process known as infiltration, outdoor air flows into the house through openings, joints, and cracks in walls, floors, and ceilings, and around windows and doors. In natural ventilation, air moves through opened windows and doors. Air movement associated with infiltration and natural ventilation is caused by air temperature differences between indoors and outdoors and by wind. High pollutant concentrations can remain in the indoor air for long periods after some of these activities, and The use of cleaning products and pesticides in housekeeping.
Starting Points of action
IAQ is a too much relevant issue for health (e.g. respiratory diseases) Indoor air tends to be more polluted than ambient air, but... Despite having been tackled for long by public policies, outdoor ambient air keeps being a basic pollution source for indoor air Buildings as diodes between two environments must be addressed under a holistic and lasting intervention/ perspective which should integrate the concerned aspects of policies related to safety, health, energy efficiency and sustainability of buildings Materials and products going inside buildings shall be such that they won’t become relevant sources of air pollution whatsoever Occupant’s activities and behaviour indoors to call upon public awareness and responsible participation
Areas of Investigation Environmental measurements Building and ventilation characterization Time activity assessment and Occupant’s health assessment. Monitoring Objectives
Defining the objective. Evaluating the methods for measurement of pollutants Individual exposures of the receptors within the building. Identifying the effects of variations in ventilation on IAQ. 3
Environmental Scientist Epidemiologist (public health expert) Building Design Engineer (Architect) HVAC Engineer Building Manager (management person) Analyst
Strategies of implementation Integration of health into know-how of architecture, engineering, managerial and social sciences (multi-disciplinary approach) Involvement of all the sectors of the public administration (Regional and Local Governments) When appropriate, use of market and fiscal incentives Information and health education to promote active role of population in health prevention Proposed actions at regulatory and Technical levels 1. Functional requirements of the indoor environments and standards/guideline values for indoor air quality Definition of minimum IAQ requirements and recommended IAQ values for: offices and public buildings, schools, hospitals, residences, and transport means. Ventilation standard setting Inclusion of radon preventive measures in building codes Definition of reference measurement methods for indoor air pollutants Accreditation of private and public services for IAQ 2. Specific actions for sources or pollutants
Radon Particulate matter Gaseous Pollutants Biological agents Allergens Construction and furnishing materials Chemical commodities
3. Production and management of buildings Revision of existing norms on building hygiene, HVAC hygiene and building codes Guidelines for building design, minimum ventilation requirements, and ventilation testing Norms on building commissioning 4
Norms for building, HVAC and technical installation maintenance and institution of the “maintenance recording book” Accreditation of the building maintenance and IAQ consultant services 4. Technical education and training Education and continuing education programmes for professionals of HVAC engineering, building sector, and health and environment professionals Inclusion of IAQ information in the high school and university curricula and education of teachers Specific training of the National Health Service personnel on risk assessment, remedial technical measures, and prevention in the indoor environments 5.
Information and health education of the population Preparation of scientifically sound information materials and their dissemination in co-operation with the professional associations of medical doctors, engineers, architects and building related professions. Set up of information campaigns for the general population and specific groups (asthmatics, etc.)
An integrated IAQ protocol An integrated IAQ protocol includes following components that need to be performed:
Selection of type of building i.e. commercial, residential, sensitive. Conducting an IAQ building audit; Diagnosing IAQ related health problems; Selection of pollutants of concern corresponding to the type of building; Designing the monitoring programme of selected pollutants of concern; Setting up of IAQ guideline values for selected pollutants Establishing an IAQ management and maintenance program to reduce IAQ risks; Protecting occupants from exposures to construction/renovation contaminants; and Calculating the cost, revenue, and productivity impacts of planned IAQ activities.
IAQ protocol needs to incorporate three major areas of investigation: Environmental measurements, building and ventilation characterization, and an occupant questionnaire. Framework for understanding how indoor and outdoor sources of pollution together with the ventilation affect the IAQ in buildings is one of the essential requirements. The monitoring protocol also include the schedule of measurements, the specifications of the measurement equipment’s’, how to select the representative space(s), and how to select the sampling sites in each space. Data collection program allow entry of majority of data and its findings in a readily accessible database so that it can be used by any interested party for a number of applications: developing the distribution of IAQ/ building/ventilation characteristics, predicting IAQ (modeling), developing new hypothesis, establishing standard protocols, examining the relationship of symptoms to building and ventilation characteristics, exposure assessment/modeling, developing guidelines for building design and orientation, construction, operation and maintenance etc.
The first step in the preparation of a protocol is the definition of the sampling objectives or of the hypothesis to be tested. These objectives are generally problem oriented and so need ‘mapping’ or documentation of complaints in the building, control of compliance with standard or exposure limits and identification of the sources. Other objectives are the evaluation of the methods for measurements of pollutants, individual exposures of the receptors within the building, the identification of the effects of the variations in ventilations on IAQ. Each of these objectives call for different protocols and a detailed description of the aim is essentially the first step in any planning of the protocol. Once the sampling/monitoring objectives have been defined, the second step is to establish a list of all relevant sampling/monitoring variables and their variation range as given below: Indoor Environment Contaminants: Biological exposure: Allergens or microbiological; Chemical exposure: Dust, aerosols or vapors; Physical exposure: Acoustic environment, humidity, air movement, thermal environment Emission controlling variables: Building site and type, materials, ventilation type, outdoor pollution, emission rates, elimination rates Co-variables for human reactions: Genetic factors, personal co-factors, building related cofactors, social environment, work environment, exposure times Human Reactions: Symptoms from eyes, nose and upper airways, throat, mouth, lower airways, stomach, heart, ear, hyper-reactivity, skin reactions, heat balance, neurological effects, psychological effects, changes in human activity patterns. Non-human reactions: From animals and plants and effects of buildings and other properties. The variation range of each variable may be found in literature or by pilot study. The pilot study may provide a data base of frequencies and variations as well as other basic quantitative information. For each of the selected variables, a sampling/monitoring specification is then established. I. Identification of relevant measuring parameters The comfort parameters (temperature, relative humidity and airflow) are important dimensions of indoor air quality. Generally, independent measurements of temperature and relative humidity will be sufficient. However, some instruments will integrate these and other measurements and provide a read out of comfort consistent with ASHRAE Standard 55-1992. For temperature and humidity measurements, instruments can be a simple thermometer and humidity gauge, a sling psychrometer, or an electronic thermo hygrometer. Such meters integrate several comfort parameters and will provide a direct indication as to whether comfort is in the acceptable range according to ASHRAE Standard 55-1992. The environmental measurements include measuring Carbon Dioxide (CO2) and other contaminants. CO2 measurements are done by using sorbent tubes, which are readily available and are inexpensive. However they are with accuracy of only 25% and are not of much value for indoor air quality diagnostics. Digital infrared spectrometry though more expensive is mostly used with more accurate and appropriate measurements. Indoor CO2 should be measured at peak values. However, if measurements in the occupied space are 6
ever above 1000 ppm, check for improperly vented combustion appliances, which could also be producing carbon monoxide (CO). Check the CO2 levels outside; and calculate the indoor-outdoor values and compare with the above mentioned thresholds for 15 and 20 cfm per occupant. If neither of these conditions can explain why the CO2 levels are above 1000 PPM, it is a valid presumption that the outdoor air ventilation rate is too low. Real-time measurements of CO2 with data-logging equipment can be also be used to see how CO2 values rise and fall in an occupied space during the day, reflecting the pattern of changing occupancy, or changing outdoor air ventilation rates. This can provide clues as to what is happening in the building and this information can help in the diagnostic process. Most of the IAQ problems can be solved with investigation of CO2 and ventilation indoors without measuring specific contaminants. However, their measurements are sometimes helpful to clearly identify the sources and target contaminants to measure specific contaminants that have no acute affects but which could cause serious long term illness. This would help in taking mitigation measures to control the contaminant. When measurements are taken, qualified, experienced persons should take them and adhere to protocols and quality assurance procedures. Other essential parameters for IAQ measurement may include respirable suspended particulate matter (RSPM – PM10, PM2.5, and PM1.0); volatile organic carbons (VOC) including formaldehyde; Ozone (O3); carbon monoxide (CO). Observational Data: (i) average number of people in the venue, (ii) activities in the venue viz. burning activities, indoor exercises etc. (iii) age-group, socio-economic status, food & smoking habit, (iv) interaction on the intrusion of neighbor-hood pollution, (v) building orientation, height, exit (door) / windows details / ventilators, (vi) compliance of field protocols (vii) health records / disease records etc. are very important towards correlation of indoor air quality data. II. Sampling locations The optimal sampling site depends on the sampling objectives. If the sampling is planned for a specific environments (offices, residential dwellings etc.), the locations are preferred inside these environments. However, if the sampling/monitoring are representative of a given type of residences, commercial buildings, schools, hospitals, the investigators must first ensure the representatively in his selected sampling sites. Least potential problem control zone also needs to be considered, while identifying the sampling sites in specific environments. After selecting proper sampling/monitoring sites, the sampling/monitoring locations inside the environment or building must be considered. This is important as the air inside the environment is not uniformly distributed. One strategy is to locate and investigate the areas of highest concentrations of contaminants. Woods et al. (1985) and Maldonado and Woods, (1983) have suggested a procedure for choosing the sampling locations inside a residence using four concepts: I. Location of the problem or contaminant source. ii. The relative exposure index (REI) or iii. The ventilation effectiveness (VE) and iv. Occurrence of complaints REI and VE methods use tracer gas technique for identifications of problem areas within the building. Later, for mathematical analysis and predictions, each sampling/monitoring location will represent a homogeneous microenvironment which means that variance of 7
variables under consideration in each microenvironment will be smaller than variance among the averages for different microenvironments (Moschandreas, 1981). Therefore different microenvironments constitute together the entire non-homogeneous sampling/monitoring microenvironments while each sampling/monitoring location is representing a homogeneous microenvironment. Each of this microenvironment must be decided prior to sampling/monitoring and separate sampling/monitoring protocol may be fixed for each of them. The size of the microenvironment depends upon the variations in space and time of the selected variable. In addition to sampling/monitoring in the building, samples from the microenvironment outside are of particularly important for indoor/outdoor (I/O) analysis and also for locating the dominant source of pollution outside. III. Time of sampling/monitoring The contaminants concentrations indoors are related with cofactors such as humidity, human activity and air temperature. The time of sampling/monitoring must then be chosen accordingly so as to minimize the influence of the cofactors e.g. when the potential cofactors are expected to be constant and at average level. Such choice of time may not be acceptable or achievable all the time in relation to the overall aims of the investigations. Hence the sampling/monitoring programme must always allow estimate of the range of variations of relevant cofactors. For Indian scenario, the timing protocols proposed are:
Residential (morning & evening, one hour in each case) Schools / colleges /educational institution (two working hours) Offices (two working hours) Health care units (morning and evening, one hour in each case) Restaurants (two hours in the evening) Museums/Historical Buildings (two hours during the visiting hours) Industrial establishments (short time or long time during working hours)
Note: Full day monitoring protocol is also proposed as and when required in some cases of specific environment types IV. Duration of sampling/monitoring The sampling duration must represent ‘peak’ exposure and ‘average’ exposure indoors. Both long term and short term sampling/monitoring may be required to reflect the desired time resolution of the sampling/monitoring programme. The greatest time resolution obtainable is the shortest sampling/monitoring duration and interval. In addition to the sampling /monitoring efficiency together with the sensitivity of the analytical method also determines the sampling/monitoring duration. For chemical characterization of pollutants / species, long duration monitoring is specifically required. Short time sampling/monitoring (< 15 min) is chosen for investigating acute effects; investigation of chronic effects are evaluated by carrying out sampling/monitoring for longer duration of several hours or even days.
V. Number of samples/monitored data The number of samples or data points must be planned prior to start of sampling/monitoring. It is needed so that the results are within the desired confidence limits. To accomplish this, pilot studies are conducted. The distribution of contaminants indoors is approximated by a logarithmic normal distribution which is characterized by the geometric mean and geometric standard deviation. Corn (1985) has described thumb rule to find out the number of samples/data points in the desired confidence interval. In any event, minimum three samples/ monitored data should be collected before any statement is made. If the range of these exceed 25% of their average, additional samples/monitored data points should be obtained. NIOSH (1984) has described the procedure for maintaining the quality control of the analysis report. For Indian conditions, the following protocol is proposed: Minimum 50 a. b. c. d.
samples said to be adequate. Number-criteria may be decided, as under: 10% of residential / houses in particular location / area 05% of offices / work places 10% of class-rooms at schools / colleges / educational institutions 15% of rooms at health care centre’s
Number of samples may be based on the following criterion: By means of random numbers All corners, central place at all floors Building / house orientations Pre-dominant wind direction (up-wind and down-wind) Depending of the fuel usage Income group VI. Instrumentation For each of the relevant variables, separate sampling/monitoring instructions accompany the analytical protocol. The preparation of sampling/monitoring instructions must ensure that the finally selected sampling/monitoring and analytical method meet the objectives of investigations. That requires consultations with laboratory prior to the selection of the analytical methods. Table I describes a few common sampling/monitoring and analytical methods for measurement and analysis of the ambient indoor air pollutants and corresponding exposure factors. VII. Calibration The
sampling/monitoring instruments must be calibrated against a secondary standard prior to and immediately following sampling/monitoring. Besides, the instruments should be regularly checked for its calibration against primary standards. VIII. Building and ventilation characterization Characterization of building parameters, i.e. type, size, age, location, building fabric, its furnishing and equipment, its occupants and their activities need to incorporate in IAQ 9
protocol. The elements of ventilation, i.e. airflow rate, air volume openings in natural systems or from heating
Table 1: Sampling and Measuring Procedure/Instrumentation for IAQ study S. No.
RSPM including PM10, PM2.5 and PM1.0
Dual section, charcoal tube, polymer absorber based samplers followed by GC
Non dispersive infra red (NDIR) spectroscopy Improved West &Gaek, Ultraviolet Fluorescence
Special* (only for selected types of buildings)
Modified Jacob and Hochheiser method Chemiluminescence
UV Photometric Chemiluminescence Chemical method Solvent extraction followed by HPLC /GC analysis Anderson samplers, Gravimetric followed by culture method
Formaldehyde Microbial Agents
For indoor space carrying capacity For Air change rate (ACH) For Air circulation
Sampling/Monitoring procedure/instrument Gravimetric/light-scattering/ beta attenuation based instruments
Sensitivity Air flow-1.1 lpm or recommended flow for low volume or medium volume sampler /Measuring range0.20-32 microns/Resolution±2 µg/m3 In GC, retention time of various organic compounds is varies/Stationary phase is most influencing the separation of compounds Least count-0.1ppb Reflective filter for high sensitivity/ A lower detection limit of 30 ppb When the NOx measuring system is calibrated using NO2 standard gas, its sensitivity for NO becomes higher than the sensitivity of the NO measuring system that is calibrated using a standard gas of NO if the converter efficiency is less than 100% Precision-0.003 ppm/flow rate-1to 3 lpm Injection volume-5 to 100 µL Incubation @ 37oC for 24hrs
IR based IAQ monitors
Least count- 1ppm
Air flow rate
Tracer gas technique/ airflow grids/ pitot tubes
Grid with sensitivity of 1.5 to 30 min/sec as per BS1042
Thermometer, thermo hygrometer
Least count-1oC/Wet bulb maximum- 64oF for winter & 68oF for summer as per ASHRAE 55-1992
humidity gauge, psychrometer,
Least count-1%/ 30% to 60% for both winter & summer as per ASHRAE 551992
Ventilation and air conditioning (HVAC) system are important to IAQ. Its information is important to develop the protocols for the operating set points and schedules consistent with good IAQ performance. Measurement instruments and techniques, which are generally available to building personnel, can be extremely useful in assessing the performance of the right ventilation system for both exhausting and diluting pollutants. Useful measuring tools include: Smoke tube to measure airflow, Flow hood to measure air volume, Velocity meter to measure air velocity, and measuring CO2 to estimate the percentage of outdoor air or to generally evaluate outdoor air ventilation. It acts as surrogate index for analyzing the ventilation and so the IAQ. Besides, air flow grids can also be used to measure differential pressure and air flows in the buildings. IX. Occupant questionnaire The sampling methods for biological effects are numerous. Therefore to simplify the measurement protocol for biological effects of indoor pollutants, the ‘questionnaire’ tool is generally used. The questionnaire will collect information on various factors, i.e. general information on building (as mentioned in building characteristics), its environmental and ventilation condition, occupants and their work responsibilities, SBS symptoms and occupant’s perception on their health. However, there are ‘gaps’ in this tool such as, the questionnaire is neither able to prove causality, nor document whether the complaints are caused by ‘hypersensitivity’ or high level of indoor pollutants. In spite of these shortcomings, the questionnaire tool is invariably used in analyzing the IAQ problems. X. Sampling/monitoring administration The protocol must include proper numbering of all samples/monitored data, data sheets for each variable or co-variable. Strict storage norms and routine for the collected data must be established to secure the validity of the samples/data. Active information plan must be distributed to the occupants of the building before any study is started as the success of the IAQ study depends upon the cooperation of the individual occupant, building manager, the producer of the building material, the authorities, the resident welfare associations etc. The information activities should not be biased to any individual stakeholder of the site being investigated. XI. IAQ Prediction Models Predictions of IAQ for different types of buildings are essential in order to avoid repeated IAQ monitoring which involves money and manpower. Various modeling techniques are used to develop the IAQ models that includes the most used and simple technique based on mass balance approach. For many studies in IAQ, wind tunnel simulations can also be used which may provide coefficients controlling the air change rate (ACH), re-suspension and/or re-entrainment of the settled particulates etc. Such studies would help in eliminating uncertainties affecting the predictive efficiency of the IAQ models. Summary This report on the IAQ protocol is a check list for establishing a IAQ study protocol that includes sampling, monitoring, and analysis and prediction. After formulation of the 12
hypothesis or aim of the IAQ investigation all relevant variables and co-variables should be identified. The list of items to consider for each protocol and may act as list of contents for a standard sampling/monitoring protocol. These standard items which are to be considered during establishing the IAQ protocol can be summarized as below: Sampling/monitoring identification: Sample numbering and laboratory identification. Sampling/monitoring procedure: Sampling/monitoring method, analytical calibration, validation, sampling/monitoring dates, duration, and interval.
Sampling/monitoring site identifications: Site, type of building, age of building, floor level, location in the room, recent renovation activity. Co-variables: Ventilation system, time and status during sampling/monitoring and before sampling/monitoring; temperature and humidity; meteorological conditions; presence of biological sources like occupants and pets and plants; consumer products; smoking; appliances. IAQ modelling: Model type identification and formulation; calibration and validation. Effects: Exposure assessment and prediction; health effects Figure I describe, in a nutshell, the proposed IAQ protocol.
Figure 1: An Integrated IAQ protocol Indoor Air Quality Urban Localities
Natural + Mechanically Ventilated Buildings
HVAC buildings Air circulation indoors + measurement of ventilation
Naturally Ventilated Buildings
Identification of contaminants/ their sources Monitoring of contaminants/ ventilation/comfort parameters at various locations (at least 3 locations in each building type) Data interpretation/analysis (Indoor- outdoor / exploratory/statistical)
Prediction of IAQ
Record of occupant’s health complains (questionnaire study)
Identification of Control measures
Laying down the standards/limits for various contaminants and ventilation parameters for different building types by Govt. Bodies
Questionnaire For Indoor Air Quality Diagnostic Protocol
Name of Person Interviewed Site Location (Address) Date & Season Area & Locality Carpet Area Home age Height of Home No. of stories in house No. of rooms in the house Roofing material Tile / Thatched / Concrete / Corrugate Iron / Others (Specify)
Wall construction material Brick wall / Thatched / Concrete / Corrugate Iron / Wood / Mud / Others (Specify)
Floor construction material Concrete / Brick / Wood / Mud / Bamboo / Others (Specify) House ventilation related factors Acceptable / Somewhat Acceptable / Somewhat Unacceptable / Unacceptable No. of windows in house No. of doors in house Allow cross ventilation? (Yes/No)
Chimney/Exhaust Fan? (Yes/No) Air Conditioning & No. of Fans No. of family members (Adult, Children & Sick) Average time a person stays indoor Family income (monthly) Total monthly (cash) expenditure of the household INDOOR CONTAMINANT SOURCES No. of persons who smoke Cooking devices Gas Stove / Electric / Kerosene Stove / Mud Stove / Others (Specify) Fuel type Firewood / Sawdust / Tree residue / Straw / Rice husk / Jute Sticks / Bagasse / Briquette / Animal residue / Charcoal / Kerosene / Piped natural gas / LPG / Bio gas / Electricity / Others (specify) Cooking Oil Mustard Oil / Refined Oil / Olive Oil / Ghee / Others How many times a day does household typically cook? Insecticides / Hair spray / Cleaning Solvents / Cologne / Perfume / Air freshener / Kerosene Storage Cans Does the residence have attached garage or vehicle parking area? (Yes/No)
Furniture & Upholstery Pets? (Yes/No) Have you noticed any unpleasant odor(s)? (Yes/No)
OUTSIDE CONTAMINANT SOURCES Heavy Vehicular traffic nearby? (Yes/No) Other stationary sources nearby (1000-ft radius) HEALTH ISSUES What health complaints have you experienced? Allergies / Dermatitis or other skin problem / Sinus / Cold or Flu / Nausea or Dizziness / Eye or Nose irritation / Headache/Mental fatigue or any other (Specify) When do the symptoms occur? How often? All the Time / Anytime / A.M. / P.M. Any other comments
References Corn M. (1985) Strategies of air sampling. Scand.J.Work. Envir.Hlth 11, 173180. Maldonado E.A.B. and Woods J.E. (1983) A method to select Locations for indoor air quality sampling. Building Envir. 18, 171-180. Molhave L. (1986) Indoor air quality in relation to sensory irritation due to volatile organic compounds. ASHRAE Trans. (Dec.) paper No. 2954. Moschandreas D.J. (1981) Exposure to pollutants and daily time budgets of people. Bull.N.Y.Acad. Med. 57, 845-859. NIOSH (1984) Manual of Analytical Methods, 3rd edn, Vol.1, pp.15-28. Woods J.E., Krafthefer B.C.and Janssen J.E. (1985) solutions to indoor air quality problems in light housing, presented at Energy ’85, Washington DC, March 1985.
Kindly send your comments/suggestions to: Prof.Mukesh Khare [email protected]
Dr.D.Saha [email protected]