Air pollution and its impact on health: Comparing findings in China with findings in Europe and the USA Kristin Aunan, CICERO CCICED, October 29, 2007, Beijing

2 16 of the 20 most polluted cities in the world are Chinese What are the health benefits of abating air pollution? Policy option EmissionExposure Exposure - response Physical benefit Valuation Monetary benefit

3 Deaths from diseases associated with air pollution exposure are frequent in China (2002) Annual deaths per 100,000 people. Source: WHO, 2004

4 Why should there be differences between d-r coefficients across countries? Differences in composition of air pollution Demographic factors, e.g. age distribution Health status and socio- economic conditions Access to health services

5.. differences may (misleadingly) be due to Confounding factors (e.g. exposure to indoor air pollution) Conversion factors between different PM fractions (e.g. TSP to PM10) Classification of disease (ICD 9, ICD 10)

6 Dose-response for acute all-cause mortality (time-series studies): Very good agreement across regions End-point (air pollutant) China (meta-analysis) Aunan & Pan, 2004 Europe (APHEA II) Reanalysis USA (NMMAPS) Reanalysis USA Harvard 6 cities Reanalysis All-cause deaths (PM10) 0.03 (HEI, 2004: ) All-cause deaths (SO 2 ) 0.04 (HEI, 2004: ) No evidenceNot included (Eastern Europe: Western Europe: ) Percent change in health outcome per 1 g/m 3

7 Dose-response for other end-points (time-series and cross-sectional studies): Less agreement End-point (air pollutant) China (meta-analysis) Aunan & Pan, 2004 Europe (APHEA II) Europe (Kunzli metaanalysis) USA Hosp. admissions (CVD) P NMMAPS (US-EPA, 2003) Hosp. admissions (CVD) SO Hosp.admissions (resp.) PM (HEI, 2004: ) NMMAPS (US-EPA, 2003) Hosp.admissions (resp.) SO Chronic Resp. illness Adults PM Chronic Resp. illness Children PM Chronic bronchitis Adults PM Portnay Mullahy, 1990; Schwartz, 1993; Abbey et al., 1993 Chronic bronchitis Children PM Ware et al., 1996; Dockery et al., 1989 Infant mortality0.39 Meta-analysis (Eastern Europe, USA, S.Korea, Mexico) (Aunan and Pan, 2004)

8 Generally: Large variations across studies for most end-points

9 How to deal with long-term effects on mortality in China? Shortterm time-series studies do not capture the long-term cumulative effects of pollution exposure No long-term cohort studies in China (or similar countries) Cohort studies from USA (Pope et al., 1995, 2002) yield implausibly high risks in China World Bank 2007: Use Pope et al. (low pollution areas) and cross-sectional Chinese studies (high pollution areas -Shenyang and Benxi) and adjust a logarithmic function

10 A compromise solution (gives around 400,000 premature deaths in urban China in 2003)

11 Avoided deaths mean life years gained Life years gained per person in cohort, estimated for a 10 g/m 3 reduction in PM10 exposure (Chinese life table for 2003 and Pope et al. Dose-response coefficient). life expectancy at birth:~0.3 year (From Aunan et al., 2004)

12 USA Six cities study (Dockery et al. 1993): life expectancy at birth: ~ 0.8 year per 10 g/m 3 PM10 Figure taken from J. Schwartz, testimony, 2007

13 COPD: An important health endpoint for which knowledge is scarce Global Health Statistics, Murray and Lopez, 1996 Incidence rate Per 100,000 Prevalence rate Per 100,000 Average duration7.8years Ministry of Health, /2 year prevalence (huan bin lu)750Per 100,000 Estimated average duration12.8 (?) years What is the incidence rate and prevalence rate in China? Regional differences?

14 Conclusions Acute effect om premature mortality: –High degree of certainty and coherence across regions (d-r and baseline rates) –But no studies on infant mortality Better to transfer d-r for chronic mortality effects than to omit –Long-term cohort studies in China needed! Chronic respiratory diseases (e.g. COPD): –Large uncertainties remain (d-r and baseline rates) Data on present frequencies of health outcomes and exposure levels are insufficient, especially in rural areas