1. WORK OF THE UNITED KINGDOM AIR QUALITY EXPERT GROUP (AQEG)
Roy M. Harrison
Division of Environmental Health and Risk Management, University of Birmingham
(on behalf of Professor Mike Pilling, Chair of AQEG)

2. AIR QUALITY EXPERT GROUP REPORT ON PARTICULATE MATTER
Chapter 1 – Introduction
Chapter 2 – What is PM?
Chapter 3 – Health
Chapter 4 – Sources
Chapter 5 – Measurements
Chapter 6 – What do the measurements tell us?
Chapter 7 – Trends
Chapter 8 – Modelling
Chapter 9 – Discussion
Research Recommendations

3. WHAT DO AIR QUALITY MEASUREMENTS TELL US ABOUT SOURCES, PROPERTIES AND SPATIAL DISTRIBUTIONS?
Topics include:
Analysis of data for PM10, PM2.5, PMcoarse, particle number (CPC), size distribution (SMPS) and some specific chemical components (e.g. metals, PAH).
Spatial distribution of concentrations – on micro, meso and synoptic scales.
Episodicity and its relation to sources
- e.g. secondary, Saharan dust, ocean storms, forest fires, construction and demolition, road traffic, “bonfire night”.
Use of concentrations and chemistry to identify sources.
Receptor modelling
Relationships to other pollutants

4. WHAT DO AIR QUALITY MEASUREMENTS TELL US?
Typically recorded hourly – PM10 and PM2.5 (TEOM) particle number count (CPC), particle size distribution (SMPS)
Three hourly: elemental and organic carbon (R&P)
Twenty-four hourly: PM10 and PM2.5 (Partisol and KFG), SO42-, NO3-, Cl-
More than 24-hours: trace metals, POPs

5. WHAT DO AIR QUALITY MEASUREMENTS TELL US?
Use of time-integrated (24-hour) samples:
Examples
Sea salt episodes
Road traffic increments

6. SEA SALT EPISODES Coastal site (Peacehaven, Sussex).
Daily PM10 exceeds 50 µg m-3 AQS on a significant number of occasions.
At the inland site (Horsham; 30 km inland), PM10 decreases with increasing wind speed.
The coastal increment (Lewes minus Horsham) increases strongly with wind speed.
Data analyses by David Carslaw (Kings College, London).

7. Daily mean PM10 at Lewes (Peacehaven)

8. Daily mean PM10 at Horsham

9. PM10 daily mean coastal increment

10. SEA SALT AT INLAND SITES
Data from London and Birmingham.
24-hour mean chloride related to distance travelled over sea in preceding 24-hour period.
Data from Dr Alan Jones (University of Birmingham).

11. Movement of air mass towards sampling point

12. Mass of chloride measured v distance air mass travelled
over sea in previous 24 hours

13. THE ROADSIDE INCREMENT
Determined by sampling at nearby roadside and urban background locations.
Measurements of mass (PM10 and PM2.5) and major component chemical composition.
Influence of street geometry upon roadside increment evaluated.
Data from University of Birmingham.

14. AIR SAMPLING
Four roadside locations, three in London and one in Birmingham.
For each roadside side, one nearby urban background site is run simultaneously.
Samples collected by dichotomous Partisol over
24-hours.
Sample collection took place across all seasons of the year. T2

15. T5

18. T10

23. T14

24. CONCLUSIONS
Twenty-four hour average air quality data can give useful insights into:
coastal sea salt episodes (PM10)
transport of sea salt inland (chloride)
air circulations in urban environments
(PM mass)