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

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0 100 200 300 400 500 600 700 800

Beijing

Guangzhou

Taiyuan

Lanzhou

Shanghai

Tokyo

New York

Los Angeles

Rio de Janeiro

Mexico City

Delhi

NO2

SO2

TSP

mg/m 3

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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Deaths from diseases associated with air pollution exposure are frequent in China (2002)

Annual deaths per 100,000 people. Source: WHO, 2004

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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

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.. 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)

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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: 0.04-0.05)0.04-0.06 0.02-0.03 0.07

All-cause

deaths (SO2)

0.04

(HEI, 2004: 0.04-0.05)0.03-0.06 No evidence Not included

(Eastern Europe:

0.01-0.04

Western Europe:

0.03-0.06)

Percent change in health outcome per 1 mg/m3

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Dose-response for other end-points (time-series and cross-sectional studies): Less agreement

End-point (air

pollutant)

China (meta-analysis)

Aunan & Pan, 2004Europe (APHEA II)

Europe (Kunzli

metaanalysis)USA

Hosp. admissions (CVD)

P100.07 0.04-0.05 0.13 0.10 NMMAPS (US-EPA, 2003)

Hosp. admissions (CVD)

SO20.19 0.07

Hosp.admissions (resp.)

PM10

0.12

(HEI, 2004: 0.07-0.16)0.09 0.13 0.10-0.40

NMMAPS (US-EPA, 2003)

Hosp.admissions (resp.)

SO20.15 0.05

Chronic Resp. illness

Adults PM100.31

Chronic Resp. illness

Children PM100.44

Chronic bronchitis Adults

PM100.48 0.91-1.27

Portnay Mullahy, 1990;

Schwartz, 1993; Abbey et al.,

1993

Chronic bronchitis

Children PM100.34 2.5

Ware et al., 1996; Dockery et al.,

1989

Infant mortality 0.39

Meta-analysis (Eastern Europe,

USA, S.Korea, Mexico) (Aunan

and Pan, 2004)

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Generally: Large variations across studies for most end-points

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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

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

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Avoided deaths mean life years gained

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

Po

ten

tial

lif

e ye

ars

gai

ned

Years of age

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). life expectancy at birth:~0.3 year

(From Aunan et al., 2004)

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USA

Six cities study (Dockery et al. 1993):

life expectancy at birth: ~ 0.8 year per 10 mg/m3 PM10

Figure taken from J. Schwartz, testimony, 2007

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COPD: An important health endpoint for which knowledge is scarce

Global Health Statistics, Murray and Lopez, 1996

Incidence rate 1990 345 Per 100,000

Prevalence rate 1990 2499 Per 100,000

Average duration 7.8 years

Ministry of Health, 2004

1/2 year prevalence (huan bin lu) 750 Per 100,000

Estimated average duration 12.8 (?)years

What is the incidence rate and prevalence rate in China? Regional differences?

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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