Air Pollution and Health:

An introduction

Ferran Ballester

Unit of Epidemiology & Statistics

Valencian School of Studies for Health-EVES

Air pollution projects involved:

APHEAAPHEISEMECAS

LiteratureThere are many articles

and books on air pollution and health

There are also useful resources in Internet.

OBJECTIVES:

• Introduce the basic concepts on air pollution and health

• Comment on the most used epidemiological designs

• Present the results of some of the main studies carried out in recent years

Hippocrates

–Meuse Valley, Belgium (1930)

–Donora, Pennsilvania, USA (1948)

–London, UK (1952)

Air Pollution Major Episodes in the mid XXth

century

The London Fog

The London Fog

December 1952

0

100

200

300

400

500

600

700

800

900

1000

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

0,000

0,500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

5,000

Black Smoke Central Hall mg/m3

Daily deaths, London

0

100

200

300

400

500

600

1958 1960 1962 1964 1966 1968 1970 1972

Anual average of black smoke (in

g/m3) London 1958-1971.

Major emission sources of air pollutants

SO2 VOCsNOXPM

Power Generation

Domestic Dwellings Industry

Pb

Stationary Emission Sources

CO VOCsNOXPb

Petrol

PM

Diesel

Mobile Emission Sources (Road Traffic)

Major Air Pollutants (1)

Pollutant Formation Physical state

Sources

Suspended particulates

Primary & secondary

Solid, liquid

Vehicles Industrial processes Tobacco smoke

Sulphur dioxide (SO2)

Primary Gas Industrial processes Vehicles

Nitrogen dioxide (NO2)

Primary Gas Vehicles Gas heaters and cookers

Carbon monoxide (CO)

Primary Gas Vehicles Tobacco smoke

Major Air Pollutants (2)

Pollutant Formation Physical state

Sources

Volatile organic compounds (VOCs)

Primary, secondary

Gas Vehicles, industry, tobacco smoke

Lead (Pb) Primary Solid (fine particulates)

Vehicles, industry

Ozone (O3) Secondary Gas Secondary to photo-oxidation of NOx and VOcs)

Health Effects of Air Pollution

•Mortality •Cardiopulmonary Hospitalizations•Emergency department or outpatient visits•Symptomatic exacerbations•Changes in lung function•Cardiopulmonary symptoms•Upper respiratory illnesses•Lower respiratory illnesses

Other Effects of Air Pollution

Immune System; AllergiesAllergic Asthma, Allergic RhinoconjunctivitisExtrinsic Allergic Alveolitis / Hypersensitivity

Central Nervous SystemToxic Damage of Nerve CellsMental retardation

Carcinogenic EffectsLung Cancer, Leukemia

Reproductive effectsInfant mortality, Low weight birth

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Annoyance, discomfort

Symptoms

Medication

Restricted activity

Visits to doctors

Emergencies

Hospitalizations

Deaths

Number of persons concerned

ADVERSE HEALTH EFFECTS

Health effect assessment

•Toxicological studies•Epidemiological studies

Basic study designs in air pollution epidemiology

Exposure

Unit of observation

Acute Chronic

Aggregated

Time Series (counts):Mortality, Hospital Admissions Emergencies

Episodes, interventions

Ecological (rates): Mortality Morbidity

Cross-sectional

Individual Panel studies: Symptoms/DiseasesLung Function

Cohort studies

Cohort studies: MortalitySymptoms/DiseaseLung Function

Cross-sectional

Exposure assesment approaches in epidemiology

of air pollution

• Categorical exposure (high vs low) • Measured (or modeled) outdoor

concentrations • Measurement of indoor and outdoor

concentrations• Estimation of individual exposure using

indoor, outdoor along time-activity diaries• Direct measurement of personal

exposures• Measurement of biomarkers of exposure

COST

VALIDITY

Results from some epidemiological studies

•Time series•Cohort studies

•Intervention studies

Relationship between the factors implied in the time series

epidemiological studies of air pollution

GEOPHYSICAL FACTORSSeasonalityAnnual cycles

METEOROLOGYTemperatureHumidity, others

AIR POLLUTIONParticulates, SO 2, NO 2,O 3, CO...

HEALTHFunctional changes,emergency visits,admissions, deaths.

SOCIO-CULTURAL FACTORSWeekly patterns, holidays, unusual events,..

CORRELATESInfluenza

GEOPHYSICAL FACTORSSeasonalityAnnual cycles

METEOROLOGYTemperatureHumidity, others

AIR POLLUTIONParticulates, SO 2, NO 2,O 3, CO...

HEALTHFunctional changes,emergency visits,admissions, deaths.

SOCIO-CULTURAL FACTORSWeekly patterns, holidays, unusual events,..

CORRELATESInfluenza

GEOPHYSICAL FACTORSSeasonalityAnnual cycles

METEOROLOGYTemperatureHumidity, others

AIR POLLUTIONParticulates, SO 2, NO 2,O 3, CO...

HEALTHFunctional changes,emergency visits,admissions, deaths.

SOCIO-CULTURAL FACTORSWeekly patterns, holidays, unusual events,..

CORRELATESInfluenza

APHEA1 cities

Population > 25,000,000

APHEA1 FINDINGS 1. All pollutants studied have small acute effects on

the daily total, cardiovascular and respiratory mortality.

2. Particulates and ozone levels were consistently associated with respiratory and COPD admissions.

3. NO2 levels were associated with asthma admissions.

4. The effects were observed in locations where, in the majority of days, air pollutant levels were well below the set (W.H.O., E.C., U.S.E.P.A.) standards at that time.

APHEA2

•EC Funded•30 cities•43 million inhabitants•Period of study: 5 years

(~ 1990-1996)

The EMECAS Project

EMECAS: Combined estimates for mortality and air pollution (1)

-0,5

0,0

0,5

1,0

1,5

2,0

2,5

3,0

TSP PM10 SO2_24h

%

chan

ge

TOTAL

CVS

RES

NO2_24h CO_24h

% c

han

ge

-2,0

-1,0

0,0

1,0

2,0

3,0

4,0

5,0

6,0

TOTAL

CVS

RES

EMECAS: Combined estimates for mortality and air pollution (2)

EMECAS: combined results for cardiovascular admissions

Particles

RR

lag

01

0.9

80

.99

1.0

01

.01

1.0

21

.03

R

F

F

F

BS

R

F

R

F

PM10

F

F F

F

TSP

CVS HD IHD CBS

1.5 %Increase in

cardiac admissions

Harvard Six-City Cohort StudyRelative risk of mortality and long-term exposure to PM2.5

Dockery et al, 1993

RR

Annual mean PM2.5 (g/m3)

1,00

1,05

1,10

1,15

1,20

1,25

1,30

0 10 20 30 40

1.01 (0.95-1.06)Other causes

1.14 (1.04-1.23)Lung cancer

1.09 (1.03-1.16)Cardiopulmonary

1.06 (1.02-1.11)Total mortality

RR (10µg/m3)Cause of death

Long-term exposure to fine particulates and mortality in the ACS cohort (n:500 000)

Pope et al, 2002

Long term effectsin mortality and indicators of traffic-

related air pollution in the NetherlandsHoek et al, 2002

Cardio pulmonary

Non-Cardio pulmonaryNon-lung

cancerBlack smoke

1.34 (0.68-2.64)

1.15 (0.63-2.10)

Major road

1.95 (1.09-3.51)

1.03 (0.54-1.96)

• Close of a steel mill in the Utah Valley: particle levels,

morbidity, inflammatory process • Ban on marketing and sale of smoky

coal in Dublin: black smoke levels, mortality• Introduction of gas with low sulphur in

Hong Kong: levels of SO2 and SO4, mortality and respiratory symptoms in children

Intervention studies

Summary of estimates of particulate matter effects (1)

Acute exposures Chronic exposures Health outcomes % change per ↑

10g/m3 in PM10 % change per ↑ 5g/m3 in PM2.5

Increase Mortality* *(Population based)

*(Cohort based)

- All organic causes 0.2a - 0.6b,c - 1.0 2i - 3 - Cardiovascular 0.7c,d to 1.4 3i - 6 - Respiratory 1.3c to 3.4 - Lung Cancer 4i

Summary of estimates of particulate matter effects (2)

Acute exposures Chronic exposures Health outcomes % change per ↑

10g/m3 in PM10 % change per ↑ 5g/m3 in PM2.5

Increased hospitalisation - All respiratory 0.8 to 2.4e - COPD 1.0f to 2.5 - Asthma 1.1f to 1.9 - Cardiovascular 0.5g to 1.2h Disease: bronchitis 7 Decreased lung function (FEV1) - Children 0.15 1 - Adults 0.08 1.5

Summary• Main acute effects:

– Increase in the number of deaths– Increase in hospital admissions and emergency

visits, especially for cardio-respiratory causes– Alterations in lung performance, cardiac

problems and other symptoms and discomfort• Main chronic effects:

– Increase in the risk of death– Increased cardio-respiratory morbidity and

decline of pulmonary function

References