Black carbon and elemental carbon as possible regulated metrics Paul Quincey Dispersion Modellers User Group

5 December 2012

Talk outline 1. Soot concentration as a measure of air quality 2. The role of soot in climate change

3. Ways to measure soot concentration, including black carbon and elemental carbon 4. Defra network measurements of black carbon and elemental carbon 5. A possible regulated metric?

Soot and air quality “The barking and the spitting is uncessant, and the inhabitants of London find it in all their expectorations; the spittle, and other excrements which proceed from them, being for the most part of a blackish and fuliginous colour” John Evelyn, 1661

1950s smog

1956 Clean Air Act

Smoke – soot particles, with various molecules on their surface

Measured as “Black Smoke”

(+ sulphur dioxide)

Figure 2.1: Schematic diagram of the size distribution of airborne particles

condensation of hot vapour

Particles in ambient air

chemical route to low volatility compound

mechanical generation

homogeneous nucleation

wind blown dust sea spray volcanic particles

condensation growth primary particles

1.6

1.4

coagulation growth sedimentation

rainout/washout

0.4 0.3

0.001

0.01

0.1

2.2 transient nuclei

2.3

particle diameter accumulation mode PM2.5

1.0

10

100

(micrometres) coarse mode PM2.5-10

Iron rich dust

From AQEG (2005)

Calcium sulphate Sodium chloride Ammonium nitrate

(Fine particles at urban

Ammonium sulphate 3.9

3.1

Organic compounds Elemental carbon Bound water

5

background sites)

Is soot relevant for health effects? - Yes

Is soot relevant for health effects? - yes

Is it the only relevant metric for health effects – no

Cloud formation due to aerosol from ships

http://earthobservatory.nasa.gov

Central Washington University

Black carbon on snow

Aerosol direct effect: absorption and reflection by particles in the atmosphere

2011 UNEP & WMO report “Black carbon and ozone in the lower atmosphere are harmful air pollutants that have substantial regional and global climate impacts.”

Soot is a primary pollutant

The decline of sulphur dioxide and “black smoke” 1962-1996

• 2011 Marylebone Road / Harwell ratio of

PM10

~ 2.5 [35 vs 14 μg.m-3]

Black Carbon

~ 20

• Berlin LEZ developments

[10.3 vs 0.5 μg.m-3]

May 2012 – Gothenburg Protocol revision “The Gothenburg Protocol will be updated setting more ambitious targets to reduce trans-boundary air pollution. In particular, the revised objectives of the Protocol will see a reduction in EU emissions of around 60% for sulphur, 40% for nitrogen oxides (NOx), 30% for volatile organic compounds (VOCs), 6% for ammonia and 20% for particulate matter compared to 2005 levels. A paper recently published by the European Commission indicated that a limited number of air quality measures can substantially mitigate global warming. As announced in a joint statement by the Danish EU Presidency and Janez Potočnik, European Commissioner for the Environment, the Gothenburg Protocol will be updated having for the first time, an international agreement that acknowledges the link between air pollution and climate change. In addition, there is an agreement to act on so called 'Black Carbon', a pollutant with short-lived climate forcing characteristics.”

Measuring soot concentration (selected) Principle Optical properties of filter samples

Instrument type White light reflectance

Term used Black smoke

Single or multiBlack carbon wavelength transmittance (aethalometer)

Multi-angle reflectance and transmittance (MAAP)

Black carbon

Instrument example - aethalometer

Absorption of specific wavelengths by collected particles : 880 nm (near-ir) and 370 nm (near-uv) High precision and time resolution Real time data - but needs “loading” correction

Measuring soot concentration (selected) Principle Optical properties of filter samples

Instrument type White light reflectance

Term used Black smoke

Single or multiBlack carbon wavelength transmittance (aethalometer)

Optical absorption of airborne samples

Multi-angle reflectance and transmittance (MAAP)

Black carbon

Photo-acoustic

Black carbon

Laser induced incandescence

Black carbon, refractory carbon

Chemical analysis of filter Thermo-optical (eg samples by thermal Sunset) decomposition with charring correction

Elemental carbon (measured together with organic carbon)

Manual Carbon Results Screen

Furnace

methaniser and FID

Organic and elemental carbon

Temp

• metals (Ni, As, Cd, Pb, Hg, V, Cr, Mn, Fe, Cu, Zn, Pt) He

O2 by ICP-MS

• sulphate, nitrate and chloride analysis by ion chromatography

OC/EC Carbon Filter dividing line22(OC/EC) • organic / elemental carbon Friday, 07 December released darkness 2012

Green Magenta Blue Red Grey

FID Response (Amount of Carbon) Attenuated FID Response Oven Temperature Amount of transmitted light Absorbance of sampler

Several EC/OC analysis methods exist – these are currently being standardised

Emission source Glasgow Urban Area

Birmingham Urban Area Birmingham Urban Area + London Urban Area London Urban Area

Solid Fuel Use

Possible Solid Fuel Use Domestic Emissions

Defra’s Black Carbon Network 2-wavelength aethalometers Hourly data

Key 1 2 3 4 5 6 7 8 9 10 11 12 13 14

Site Name Glasgow Kerbside Glasgow Centre Auchencorth Moss Birmingham Tyburn Roadside Birmingham Tyburn Background Harwell North Kensington Marylebone Road Detling Belfast centre Lisburn Dunmurry Strabane Norwich Lakenfields Cardiff 12

2010 periodicity data – Marylebone Road

2010 periodicity data – Strabane

2010 periodicity data – Harwell

Defra Particles Network SITE

HOURLY PM10 ANIONS/CATIONS

WEEKLY PM2.5 OCEC

DAILY PM10 OCEC

Birmingham Tyburn (Urban Background)

CPC

SMPS

AETHALOMETER

X

X

Harwell (Rural)

X

X

X

X

North Kensington (Urban Background)

X

X

X

X

Marylebone Road (Roadsite)

X

X

X

X

Auchencorth Moss

X

EC/OC: EUSAAR II and Quartz protocols comparison

Elemental carbon vs black carbon (urban) concentration / g m

-3

concentration / g m

20 15 10 5

North Ken EC North Ken BC

12

-3

Marylebone EC Marylebone BC

25

10 8 6 4 2 0

0

Marylebone Road Linear fit

North Kensington Linear fit

10

20

15

3

BC (g/m )

3

BC (g/m )

8

10

y = 1.2603 x + 0.4068 2 R = 0.9459

6

y = 1.1619 x + 0.0288 2 R = 0.7339

4

5

2

0

0 0

5

10

15 3

EC (g/m )

20

25

0

2

4

6

8 3

EC (g/m )

10

12

01/12/2010

01/11/2010

01/10/2010

01/09/2010

01/08/2010

01/07/2010

01/06/2010

01/05/2010

01/04/2010

01/03/2010

01/02/2010

01/01/2010

01/12/2010

01/11/2010

01/10/2010

01/09/2010

01/08/2010

01/07/2010

01/06/2010

01/05/2010

01/04/2010

01/03/2010

01/02/2010

01/01/2010

12 25

Elemental carbon vs black carbon (rural) Harwell EC Harwell BC

concentration / g m

-3

2.5 2.0 1.5 1.0 0.5 0.0

3

BC (g/m )

1.5

y = 0.8858 x + 0.203 2 R = 0.5546

1.0

0.5

0.0 0.0

0.5

1.0

1.5 3

EC (g/m )

2.0

2.5

01/12/2010

Harwell Linear fit

2.0

01/11/2010

01/10/2010

01/09/2010

01/08/2010

01/07/2010

01/06/2010

01/05/2010

01/04/2010

01/03/2010

01/02/2010

01/01/2010 2.5

A possible regulated metric? Soot concentration is a very useful Air Quality measure, with additional benefits for Climate Change. The measure to be used needs careful choice and standardisation. There would be cost implications if the measure became regulated without reduction in other requirements.

Thank you

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