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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. 16 of the 20 most polluted cities in the world are Chinese What are the health benefits of abating air pollution?.
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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
16 of the 20 most polluted cities in the world are ChineseWhat are the health benefits of abating air pollution?
Deaths from diseases associated with air pollution exposure are frequent in China (2002) Annual deaths per 100,000 people. Source: WHO, 2004
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
.. 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)
Dose-response for acute all-cause mortality (time-series studies): Very good agreement across regions Percent change in health outcome per 1 mg/m3
Dose-response for other end-points (time-series and cross-sectional studies): Less agreement
Generally: Large variations across studies for most end-points
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
A compromise solution(gives around 400,000 premature deaths in urban China in 2003)
Avoided deaths mean life years gained Life years gained per person in cohort, estimated for a 10 mg/m3 reduction in PM10 exposure (Chinese life table for 2003 and Pope et al. Dose-response coefficient). Dlife expectancy at birth:~0.3 year (From Aunan et al., 2004)
USA Sixcitiesstudy (Dockery et al. 1993): Dlifeexpectancy at birth: ~ 0.8 year per 10 mg/m3 PM10 Figure taken from J. Schwartz, testimony, 2007
COPD: An important health endpoint for which knowledge is scarce What is the incidence rate and prevalence rate in China? Regional differences?
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