Civic Exchange 2009 The Air We Breathe Conference - Experts Symposium 9 January 2009 Science to Policy presented by Ross Anderson (St George's, University of London) http://air.dialogue.org.hk

1. Science to policy
Experts Symposium on Air quality
Hong Kong 10th January 2009
Ross Anderson
St George’s, University of London

2. From science to policy
Various paradigms: NRC 1983, WHO 2000
1. Hazard identification
2. Exposure-response
3. Health impact assessment for specified
exposure scenarios (risk characterization)
4. Cost-benefit and cost effectiveness
5. Development of air quality strategy
6. Implementation of appropriate measures
7. Evaluation of benefits (“accountability”)

3. Updates of WHO guidelines
Year PM measure Guideline Notes
Annual mean
µg/m3
1970s SPM 60-90 Threshold
(Lowest observed level for health
effects ~ 150 + Safety factor of 2)
1987 Black Smoke 50 Threshold
(linked to SO2, also 50)
2000 PM10 Dose-response No threshold
2006 PM10 20 No threshold
2006 PM2.5 10 No threshold.
3
PM10 ~ 0.5 x SPM; 2 x BS; 1.3 x PM2.5

4. Long term exposure to PM and risk of mortality
in ACS cohort (~ 0.5 million people in a large
number of US cities followed for 16 years)
Adapted from
Pope et al 2002
4

5. WHO AQG: Global update 2005
Annual mean PM10 PM2.5 Basis for the selected level
level (µg/m3) (µg/m3)
Interim target-1 70 35 Levels associated with about
(IT-1) 15% higher long-term mortality
than at AQG
Interim target-2 50 25 Risk of premature mortality
(IT-2) decreased by approximately
6% compared to IT1
Interim target-3 30 15 Mortality risk reduced by
(IT-3) approximately 6% compared to
IT2 levels.
Air quality 20 10 Lowest levels at which total,
guideline CP and LCA mortality have
(AQG) been shown to increase (Pope
et al., 2002). The use of PM2.5
guideline is preferred.

6. Passing interim targets on the way towards AQG
Effect
Exposure
AQG IT-2 IT-1

7. Implications of no threshold
Concentration
Response

8. Implementation of exposure reduction
concept for PM2.5 in the UK
Health based, and quantified by cost-benefit
analysis
1. 15% reduction in average annual urban
background concentrations 2010 - 2020
2. Backstop objective (concentration cap) of
25µ/m3 applicable to all areas. To provide
minimum protection.
8
The Air Quality Strategy for England, Scotland, Wales and N Ireland, 2008