A Global Perspective on Air Pollution and Health Global Perspective on Air Pollution and Health Aaron J Cohen Health Effects Institute • What factors determine the health impacts

A Global PerspectiveA Global Perspective on Air on Air

Pollution and HealthPollution and Health

Aaron J Cohen Aaron J Cohen

Health Effects Institute Health Effects Institute

• What factors determine the health impacts of air pollution on a global scale?

• How large is the burden of disease due to air pollution on a global scale?

• What are the key uncertainties?

• Does reducing air pollution improve health?

The Environmental Risk The Environmental Risk

TransitionTransition

Smith and Ezzati 2005

Sources of fine particulate air Sources of fine particulate air

pollution vary worldwidepollution vary worldwide

Biomass Burning and Respiratory Biomass Burning and Respiratory

Health in Kuala Lumpur 1997Health in Kuala Lumpur 1997(Data from M Brauer 1997)(Data from M Brauer 1997)

Global exposure to air particulate Global exposure to air particulate

pollutionpollution

0

10

20

30

40

50

60

70

Urban Rural Urban Rural

Developed Developing

Per

cent

of

Tot

al

IndoorOutdoor

5

58

5

Exposure = Population Exposure = Population ×××××××× Time Time ×××××××× PollutionPollution

Data from KR Smith personal communication 2002

Developed Developing

In developing countries poor women and In developing countries poor women and

children are exposed to high levels of pollution children are exposed to high levels of pollution

from indoor burning of solid fuelsfrom indoor burning of solid fuels

0

20000

40000

60000

80000

6:00 9:00 12:00 15:00 18:00 21:00Time

µ = 1250 µg / m3

σ = 2500 µg / m3

Human exposure to trafficHuman exposure to traffic--related related

air pollutionair pollution

The Epidemiologic TransitionThe Epidemiologic Transition

Smith and Ezzati 2005

A: very low child and adult mortalityB: low child and adult mortalityC: low child, high adultD: high child, high adultE: high child, very high adult

Number of people at high CV risk globally in 2000Number of people at high CV risk globally in 2000

(A Rogers 2005)(A Rogers 2005)

5 m

4 m

38 m

19 m1 m

5 m12 m

46 m

18 m

36 m

7 m

45 m16 m

50 m

>175 million people at 25%+ risk >175 million people at 25%+ risk of a major CV event in the next decade, by WHO subregionof a major CV event in the next decade, by WHO

subregion

Air Pollution and SARS Mortality in Air Pollution and SARS Mortality in

thethe PRCPRC

YanYan Cui et al 2003Cui et al 2003

Two epidemiologic methods to study Two epidemiologic methods to study

air pollution and mortality: Time air pollution and mortality: Time

series and cohort studiesseries and cohort studies

Time Series studies• Exploit temporal differences in exposure

• Estimate the association between daily mortality ratesand the level of air pollution shortly before death

Cohort studies• Exploit spatial differences in exposure

• Estimate the association between long –term average mortality rates and long-term exposure to air pollution

• Estimate the association between time-to-death (e.g. YLL) and long-term exposure to air pollution

PAPA Meta Analysis Results:PAPA Meta Analysis Results:Asian Risk Estimates Similar to West; Initial Asian Risk Estimates Similar to West; Initial

Support for Extrapolating from Western Support for Extrapolating from Western

StudiesStudies

0.460.62

0.49

00.10.20.30.40.50.60.7

Percent Increase

US(90 Cities)* Eur(21 Cities)* Asia (4 Cities)

Percent Increase in Mortality per 10 micrograms of Exposure

* Estimates Using Pre-GAM Results (without revision)

LongLong--term Exposure to Fine Particulate Air term Exposure to Fine Particulate Air

Pollution and Mortality from Chronic Pollution and Mortality from Chronic

Cardiopulmonary DiseaseCardiopulmonary Disease

Source: HEI Reanalysis of the American Cancer Society Study (Krewski 2000)

CRA project and WHR 2002CRA project and WHR 2002

Estimated Impacts of Urban Air Pollution Estimated Impacts of Urban Air Pollution

Worldwide Worldwide (95% confidence intervals)(95% confidence intervals)

913

(-846, 2358)

26

(-24, 66)

1

(-1, 3)

ARI (0-5 yr.)

588

(104, 1089)

62

(10, 114)

5

(1, 9)

Lung Cancer

6360

(2140, 10129)

712

(245, 1107)

3

(1, 6)

CPD

DALYs

(x 103)

Deaths

(x 103)

AF

(%)

Cohen et al. 2004

Mortality attributable to leading risk Mortality attributable to leading risk

factorsfactors

0 1000 2000 3000 4000 5000 6000 7000 8000

High blood pressure

Tobacco

High cholesterol

Underweight

Unsafe sex

Low fruit and vegetable intake

Overweight and obesity

Physical inactivity

Alcohol

Unsafe water, sanitation, and hygiene

Indoor smoke from solid fuels

Iron deficiency

Urban air pollution

Zinc deficiency

Vitamin A deficiency

Contaminated health care injections

Occupational airborne particulates

Occupational risk factors for injury

Lead exposure

Illicit drugs

Mortality in thousands (Total 55.86 million)

High-mortality developing

Lower-mortality developing

Developed

Ezzati et al. 2002; WHO 2002

Excess Deaths from Selected Excess Deaths from Selected

Environmental FactorsEnvironmental Factors

The PAPA StudiesThe PAPA Studies

PAPA PAPA -- Public Health and Air Pollution in Public Health and Air Pollution in

Asia Asia

New Research in Asian CitiesNew Research in Asian Cities

• 9 new studies of air pollution and health in Asian Cities

• Acute Effects:

• Bangkok, Hong Kong, Shanghai, Wuhan, Chennai, Delhi, Ludhiana

• Effects of Long Term Exposure

• Guangzhou, China pilot study in elderly cohort

• Air Pollution, Poverty, and Health

• Ho Chi Minh City

The poor may suffer more health effects The poor may suffer more health effects

from air pollutionfrom air pollution

• Higher exposures� Living close to

traffic

� Roadside occupations

� Small and medium scale industries

� Use of solid fuels for cooking

• More susceptible� Poor nutrition /

immunosuppression

� Higher incidence of ‘diseases of poverty’

� Lack of timely access to health care

Studying Air Pollution, Poverty, and Studying Air Pollution, Poverty, and

Health in HCMCHealth in HCMC

Overall Objectives:

1. Develop feasible approaches to studying air pollution, poverty, and health • Methods appropriate for HCMC context• Methods suitable for use in other cities -

promote building an evidence base across Asian cities

2. Develop infrastructure for future studies of the health effects of air pollution in HCMC• Technical capacity (epidemiologic

methods, exposure assessment, analysis)• Resources (data integration, equipment)

Ho Chi Minh City Study of Air Ho Chi Minh City Study of Air

Pollution, Poverty, and HealthPollution, Poverty, and Health

Hospital-based study• Estimate the effect of short-term exposure to air pollution on hospital admissions for ALRI in young children (<5 years) in HCMC

• Compare the magnitude of the effect of air pollution on poor children vs. other children

Household-based study• Estimate personal exposures to air pollution among the poor and the non-poor• ambient air pollution • other sources (cooking with solid fuels, cottage industries)

• Estimate prevalence of respiratory symptoms in HCMC

• Survey of perceptions and economic costs

Does reducing air pollution Does reducing air pollution

improve health??improve health??

Is it worth the cost??Is it worth the cost??

UK SOUK SO2 2 Emissions and Electricity Emissions and Electricity

GenerationGeneration

19701970--19951995

Figure from Williams ML 1999

Before After

July 1st 1990: Environmental Protection Department restricted sulphur content of fuel to 0.5% by weight

The Hong Kong Air Quality Intervention The Hong Kong Air Quality Intervention

19901990

Courtesy AJ Hedley

Assessing Benefits of Fuel Sulfur Assessing Benefits of Fuel Sulfur

Reduction in Asia: Hong KongReduction in Asia: Hong Kong

Estimates of Benefits US Highway Diesel Rule

8,300

5,600

2,100

361,400

9.5 million

386,000

17,600

5,500

Emergency Room Visits

Restricted activity days

Acute respiratory symptomse.g.: new cases of croup, pneumonia

Acute asthma attacks

New cases ofbronchitis in children

New cases ofchronic bronchitis

Number of Annual Casesfor All of US

2030

MortalityHospital

Admissions

US EPA RIA, 2000US EPA RIA, 2000

Comparing Costs and Benefits US HighwayHighway Diesel Rule(Source: US EPA RIA 2000)

0

10000

20000

30000

40000

50000

60000

70000

$million/yr.

2030 ImplementationCosts

Monetized Annual2030 Benefits (avoideddeaths and othereffects)

Thank You

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