1. Effects of low level air pollution on human health
Bert Brunekreef, PhD
Professor of Environmental Epidemiology

4. Harvard Six Cities Study
Dockery, NEJM 1993

5. Harvard Six Cities Study
Dockery, NEJM 1993

6. Air Quality Standards for annual PM2.5 concentration
WHO
AQG
US EPA Standard EU
Limit
Value
The major American study is the so called American Cancer Society Study, and this graph shows the relationship between PM2.5 and mortality as it was observed in that study. What is clear from the graph is that the European Limit Value for PM2.5 of 25 microgram/m3 is very high compared to the American standard of 12 microgram/m3 and the WHO Guideline of 10 microgram/m3. The Americans have been able to reduce PM2.5 in most areas to levels below this standard. There must be something that we’re doing wrong here in Europe as we can’t seem to get our concentrations down.
Figure from Pope, JAWMA 2006 6

7. EHP
2014
WHO
AQG

8. Crouse, EHP 2012

9. Canadian census cohort, Crouse, EHP 2012
Census of 1991
2.1 M adults > 25 years
Follow up
Individual data on age, sex, minority, marital, educational & occupational status, household income, size of home community
Contextual data on neighborhood employment, education, income; urban/rural
No data on smoking, obesity, diet, alcohol, PA
PM2.5 from satellites, , 10x10 km
PM2.5 from measurements, in 11 cities (43% of population)

10. All-Cause
Mortality
WHO
AQG
Crouse, EHP 2012

11. Ecological SES covariates negatively associated with PM2.5

12. HRs per 10 µg/m3 PM2.5

13. WHO
AQG
Crouse, EHP 2015

14. WHO
AQG
R PM2.5 and O3: 0.73; R PM2.5 and NO2: 0.40; R NO2 and O3: 0.19
Crouse, EHP 2015

15. Crouse, EHP 2015
HRs per 5 µg/m3 PM2.5, 9 ppb O3,
8.1 ppb NO2

16. Pinault, EH 2016 Health survey ~300,000, age 25-90, enrolled 2000-2008
Mortality follow-up through 2011, 26,300 deaths
PM2.5 from satellite, CTM, land use and monitoring now at 1x1 km
Individual data on smoking, BMI, alcohol, diet, SES
Several ecological covariates
Pinault, EH 2016

17. Pinault, EH 2016

18. Pinault, EH 2016
WHO
AQG

19. ER 2017
Natural causes
Cardio-metabolic
IHD
Cerebrovascular

20. 61 M Medicare beneficiaries from 2000-2012
460 M years of follow-up
PM2.5 and O3 modeled at 1x1 km using satellites, CTM, land use and monitor data
No data on smoking, BMI, income etc.
MCBS subsample of 57 k subject for ancillary data
BMI, smoking and income not strongly related to PM2.5 and O3
Correlation PM2.5 and O3 was 0.239

23. Di, NEJM 2017
HR = per 10 μg/m3 PM2.5

24. Di, NEJM 2017
HR = per 10 ppb Ozone

25. EU
Limit
Value
Raaschou-Nielsen EH 2012

26. WHO
AQG
Raaschou-Nielsen EH 2012

27. Concluding remarks
Evidence for effects of long term, low level PM2.5, NO2 and O3 on mortality is increasing
Most evidence is from nationwide administrative cohorts
These cohorts often lack individual data on key (potential) confounders such as smoking, alcohol, diet
Innovative ways to indirectly adjust for these are being developed and tested
Regulatory impacts? EPA PM ISA under development, WHO AQG being revised
Burden of disease impacts? Threshold/no threshold, linear/nonlinear CRFs, non-accidental/cause specific mortality