The Health Effects of Air Pollution

Robert M. O’Keefe, Vice PresidentHealth Effects Institute

National Workshop on Improvement of Urban Air Quality of Pakistan

Lahore December 2004

Assessing the Health Effects of Air Pollution

• Health Effects Institute • Air Pollution and Health Effects• Public Health And Air Pollution in Asia

Program “PAPA”• The existing Asia science literature• New Asian studies

• Conclusions

The Health Effects Institute• Founded in 1980 to provide impartial, high-quality science on health

effects of vehicle and other emissions• Joint and Equal Core Funding from

– Government (U.S. EPA)– Industry (28 Worldwide Vehicle Manufacturers)– Today many partners worldwide: ADB, WHO, EU California ARB

(CARB), Oil, other Industries• Independent Expert Science Committees oversee and peer review all

research• Over 225 studies - Americas, Asia, Europe - ozone, carbon

monoxide, particulate matter, diesel exhaust, benzene, butadiene, methanol, others

Air Pollution and Health:What we know about the effects

Air Pollution has Many Effects• Health

– Respiratory, cardiovascular morbidity– Mortality

• Heritage– Nitric Sulfuric Acid erosion

• Natural Resources – Acidification (lake and stream biology)– Mercury deposition (fish tissue)– Visibility

• Agriculture– Ozone crop effects (~40% reduction in rice, soy yield in Pakistan

city)

– *(Wahid 2003 Veranasi)

Many Sources of Air Pollution in Asia

• Combustion– Open burning– Brick Kilns– Vehicles– Trash burning– Factories– Power generation– Cooking in slums

• Non-Combustion– Agricultural

cultivation– Street sweeping– Windblown sand– Unpaved roads– Paved roads

(asbestos, rubber etc)

– Construction

Vehicle Emissions and Exposure

• Must consider all effects of the system:– different vehicle types -

• 2 and 3 wheelers• cars• trucks and buses

– vehicle plus fuels (and fuel components)– tailpipe emissions plus evaporative

emissions– maintenance of system

Major Vehicle/Fuel Emissions

• Carbon Monoxide • Diesel Exhaust• Particulate Matter (PM)• Lead• Nitrogen Oxides (NOx)

and Hydrocarbons (HC)– Precursors to Ozone

and PM• Nitrogen Dioxide

• Air Toxics– Aldehydes

• formaldehyde• acetaldehyde• others

– Benzene– 1,3-butadiene– Methanol– Polycyclic organic

matter (e.g. PAHs)

Health Effects• Different Pollutants have Different Effects

– Carbon Monoxide - circulatory system, heart– Ozone - respiratory system, lung– Lead - nervous system, brain– PM - lung, potential effects on heart– Diesel, Air Toxics - cancer, respiratory

effects• There are potential effects of the Mixture

Health Effects• Some populations more sensitive than others

– Children– Elderly– people with heart and lung disease

• Asthma is growing– 150 million asthmatics worldwide– Increasing in most countries (2% to 5% per year)– Asthmatics much more sensitive to air pollution

Particulate Matter (PM) Health Effects

• High levels of PM (e.g. 500 /m3) known to cause premature death– e.g. London 1952

• Recent studies in US, Europe, Asia, South America have found association of PM with death at much lower levels (< 50ugm3)– no evidence of a “threshold” (safe level)

• Progress made to identify a plausible biological mechanism for these effects; results not yet definitive

PM - The Epidemiology Studies

• A Number of Epidemiology Studies

• Europe Studies Harvard 6 Cities Study

PM Health Effects - India, ThailandSource: Chhabra 2001, Pande 2001, Vichit-Vadakan, 2001

05

101520253035404550

% I

ncre

ase

in E

ffec

ts

EmergencyVisits(Pande)

ChronicEffects

(Chhabra)

Bangkok

Asthma

COAD

Cardiac

Cough

Phlegm

Lung Function

Adult Resp.

Child Resp.

Nurse Resp.

Ozone Health Effects• Known to cause inflammation in respiratory tract• Effects have been demonstrated for short term, long

term effects are less certain– some people appear to develop “tolerance”

• Reduces ability to breathe (lung function) for some people

• Increases hospitalization for asthma, other lung diseases

• New US study finds Ozone mortality effects* (Domenchi et. al 2004)

Ozone Health Effects

Figure 1. Individual Response to Ozone Exposure (after Kulle, et al,

Am. Rev.)

-5

0

5

10

15

20

25

300.1 0.15 0.2 0.25

Ozone Concentration (ppm)

% R

educ

tion

in F

EV1

• Some humans have been shown to have reduced lung function (measured as FEV1) after exposure to ozone

Diesel Health Effects• Diesel Engines have substantial advantages:

– higher fuel efficiency– lower CO and CO2 emissions

• However, they also emit high levels of :– particulate matter, NOx, and chemicals attached to the

particles (e.g. PAHs)• Two major types of health effects :

– acute effects (e.g. exacerbating asthma)– cancer effects

Diesel Effects on Childhood Illness (Brunekreef, et al Study in 24 Dutch schools)

1

1.2

1.4

1.6

1.8

2

2.2

Increased Symptoms comparing High Truck Traffic (>10,000) to Low Truck Traffic

asthma

hayfever

phlegm

HD allergy

pet allergy

wheeze last year

Assessing Diesel Cancer Risk• In general, some 30 studies of effects on

workers have provided best data• Consistent small (20-40%) increase in

lung cancer associated with exposure• Some questions about each study• Leading International Agencies (WHO,

IARC, US NIEHS, US EPA) have concluded diesel is a “probable human carcinogen”

Sulfur Dioxide• Emitted from fossil fuel combustion

• especially from coal burning facilities, high sulfur fuels

• Can impair breathing in asthmatic children and adults

• Has been associated, along with PM, with• increased aggravation of heart and lung disease• premature mortality

• Recent study in Hong Kong (Lancet 2002) has found:

• substantial reductions in SO2 emissions can result in measurable improvements in mortality and illness

1988 1989 1990 1991 1992 1993 1994 1995

020

4060

80

NO2

SO2

O3

PM10

Mic

rogr

ams

per c

ubic

met

re

Year

AIR POLLUTANT CONCENTRATIONS 1988 - 95 IN HONG KONG HALF YEARLY MEAN LEVELS

Fuel restriction on sulphur

50% reduction in SO2 after the intervention

No change in other pollutants

-6-5

-4-3

-2-1

0

15-64 65+ 15-64 65+ 15-64 65+

REDUCTIONS IN DEATHS AFTER SULPHUR RESTRICTION

All causes Cardiovascular Respiratory

% R

educ

tion

in a

nnua

l tre

nd

-1.8%

-2.8%

-1.6%

-2.4%

-4.8%

-4.2%

Air Toxics Health Effects

• Benzene– a “known human

carcinogen”– studies in U.S. and Chinese

workers have shown link between exposure and increased leukemia

• Metals– Range of effects, heart,

reproductive, – cancers

• 1,3 Butadiene– a “probable” or

“known” human carcinogen

– studies in laboratory animals and US and Czech workers have shown effects

• Aldehydes, PAH’s– Cancers, Irritants

Air Pollution and Health in Asia:The Public health and Air Pollution Program

(PAPA)

The Problem: Air Pollution in Asia: High Levels in Many Cities (2000-

2001)

Source: Benchmarking Report on Air Quality in Asian cities Stage 2, 2004 (forthcoming)

SPM Limit = 90 µg/m3 (WHO, 1979)

0

50

100

150

200

250

300

350

400

Bangk

ok

Busan

Chong

qing

Colombo

Hong K

ong

Jaka

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Kolkata

Manila

Mumba

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New D

elhi

Osaka

Pune

Singap

oreSeo

ul

Shang

hai

Tokyo

conc

entr

atio

n in

µg/

m3

SO2 NO2 SPM PM10

PM10 Limit = 50 µg/m3 (USEPA, 1997)

SO2 Limit = 50 µg/m3 (WHO, 1999)

NO2 Limit = 40 µg/m3 (WHO, 1999)

Lancet October,

2002

Environmental Burdens Premature Deaths

source: WHO Global Burdon of Disease

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The Challenge: Expanding current science base to inform Asian air regulatory decisions• Air pollution poses clear health effects• Western research is relevant to Asian populations,

however extrapolation poses challenges– Population characteristics– Pollution sources and mixes

• Are observed risks similar?, greater?, smaller? • A clear need for representative air pollution & health

studies of local Asian populations

PAPA Program• Partnership with CAI-ASIA to understand the health effects of air

pollution in Asia, now and in the future

• Active effort underway:– Published Scientific Review and Meta Analysis of what is known

today about health effects in Asian cities– Conducting series of epidemiological studies in representative

Asian cities• Understand local impact• Combine to provide Asia-wide understanding

– Publish a Comprehensive Assessment of the state of air pollution and health across Asian cities

– Build capacity of local scientists• Overall Goal:

– Quality science to inform key Asian regulatory & policy decisions

Health Effects of Outdoor Air Pollution Health Effects of Outdoor Air Pollution in Developing Countries of Asia: A in Developing Countries of Asia: A

Literature ReviewLiterature Review• Systematic identification of 140

peer-reviewed Asian studies 1980-2003

• Special focus on studies of daily changes in air pollution and health

• Conduct first ever Asian meta analysis” quantifying risks, finding initial similarities with West

• Identify knowledge gaps to guide future research

• Active communication to policy makers

Studies of Air Pollution and Health in Asia 1980–2003

Many Health Effects Studied

0

2

4

6

8

10

12

All-CauseMortality

RespiratoryMortality

CardiovascularMortality

RespiratoryHospital

Admissions

CardiovascularHospital

Admissions

Outcome Diagnosis

Num

ber o

f Stu

dies TSP

PM10PM2.5SO2NO2COO3

Daily Mortality: Initial Results:Asian Risk Estimates Similar to West

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)

New Research in Asian Cities• To strengthen base of Asian Health Science:• Eight new studies of air pollution and health now

underway in Asian cities• Acute (short term) effects studies in

• Bangkok, Hong Kong, Shanghai, Wuhan• Strong teams, quality data

• Long Term (chronic) effects• Guangzhou, China pilot study in elderly cohort

• New!• Study teams now identified in India: Chennai; Delhi;

Ludhiana

PAPA: Looking Ahead

• A Special Challenge: Understanding the interaction among air pollution, poverty, and health– In Asia high levels of air pollution, dense population, extensive

poverty are prevalent– Some initial evidence (mostly from West) that the poor face

worse effects from air pollution– Could be due to:

• Different exposures (roadside, indoor, occupational)• Poorer SES\health status (nutrition, medical care) leading to higher

susceptibility• Other factors

– Potential Public health implications could be significant• New study under design in Ho Chi Minh City to

understand poverty effects

Conclusions• Air Pollution from many sources, including vehicles,

fuels have been shown to have effects on mortality, morbidity

• Problem will grow with economic expansion• WHO estimates place air pollution mortality in hundreds

of thousands across South Asia, Eastern Mediterranean region (including Pakistan)

• While studies are extrapolated from developed world, initial PAPA Review and analysis tend to confirm results in Asian populations, though many limitations exist

• The PAPA program is building a better base of Asian health and air pollution science– New studies across Asia, with capacity building as a priority– Role of poverty in air pollution to be assessed

Conclusions• Better air monitoring needed over long term

– To determine current status, monitor ongoing progress and assess health, communicate to public

• However, Pakistan urban conditions also warrant near term action– “Visible emissions” wide-spread– Dense population level, clear exposure– Acute effects commonplace– Provided basis of action in many countries (UK,

HK, others) before comprehensive monitoring

Thank You!

Bob O’Keefe rokeefe @healtheffects.org

www.healtheffects.org