Air Pollution Background

• A widely recognized problem in developed and developing nations

• Definition: the presence of substances in air at concentrations, durations and frequencies that adversely affect human health, human welfare or the environment.

• Humans suffered from blackening of lung tissue through long exposure to particulate air in smoky dwellings going back to ancient times.

• Unhealthy air was the suspected cause of disease long before the relationship could be scientifically confirmed.

Air Pollution and Health

• A major environmental risk to health• Exposure: inhaled aerosols (particles) and

gases• Estimated to cause ca. 2 million premature

deaths worldwide/year• Exposure is largely beyond the control of

individuals– But individuals can reduce household

emissions and exposures• Requires action by public authorities at

national, regional and international levels.

Air Pollution and its Sources

• Major pollutants:– Ozone– Sulfur dioxide– Oxides of nitrogen– Particles or particulates– Carbon monoxide– Volatile organic compounds– Trace metals

Clean Air Air Pollution Sources & PollutantsMobile Source Stationary Source

Particles Sizes and Airborne Agents

Respiratory System and Air Pollutants

Particles:>100 µM contact eyes, nose and throat; can be irritants>20 µM are inhaled but do not penetrate below the throat< 10 µM enter airways and may be deposited in respiratory system<2.5 µM deposit in alveoli with high efficiency (fine particles)< 0.1 µM remain suspended to be breathed out again

US EPA Regulated Particulates• Total Suspended Particulate Matter (TSP)

– 0.1 - 30 micrometer in diameter • PM10

– aerodynamic diam. ≤10 micrometers– penetrate into lower respiratory tract; 0.1 and 10 micrometers

size range is especially important• PM2.5

– aerodynamic diam. of less ≤ 2.5 micrometers– airborne for several hours to days; long distance travel– Human respiratory system vulnerable from exposure to them– Composed of sulfates, nitrates, organic cds., ammonium cds.,

acidic materials, metals & other contaminants causing adverse health effects.

– 0.2 to 0.5 micrometer: common in combustion, waste incineration, and metallurgical sources

– 0.1 to 1.0 micrometers: significant emissions from industrial sources

US EPA Regulated Particulates, Continued

• Particles less than 0.1 micrometer diam.– Combustion and metallurgical sources

generate 0.01 to 0.1 micrometer particles. – Tend to agglomerate rapidly to yield particles

in the greater than 0.1 micrometer range • Condensable Particulate Matter

– Non-particulate matter that condenses and/or reacts upon cooling and dilution in ambient air to form particulate matter in the PM2.5 classification. within a few seconds after discharge from the stack

Sources of all Air Pollutants Measured in CaliforniaHydrocarbons (HC), Carbon Monoxide (CO), Oxides of Nitrogen

(NOx), Oxides of Sulfur (SOx) and Particulate Matter (PM)

** Residential fuel combustion, farming operations, construction, road dust, wind-blown dust, fires, waste burning, utility equipment and other miscellaneous sources.

Health Conditions Associated with Air Pollution ExposureDisease/Condition Role of Air Pollution Associated Factors

Acute Bronchitis SO2, soot, petrochem. irritative effects

Cigarette smoking may be synergistic

Acute Respiratory Infections Increased risk in young children Poverty, malnutrition, pathogen exposure

Asthma Aggravated by respiratory irritation

Pre-existing respiratory allergy; airway hyperactivity

Chronic bronchitis Cough/sputum aggravation Cigarette smoking; occup.

Death Fine particulates incr. heart and lung disease

Pre-existing heart and lung disease

Eye irritation Photochemical oxidants, aldehydes, peroxyacetyl nitrates and PM

Differing susceptibilities

Headache Carbon monoxide incr. carboxyhemoglobin

Smoking also increases carboxyhemoglobin; indirect effect

Lead toxicity Contributes to body burden Lead exposure sources at home

Common Health Effects of Ambient Air Pollution• Respiratory symptoms most common• Cough, nose and throat irritation & mild shortness of breath.• Often associated with eye irritation and a sense of fatigue• Exacerbation of allergic symptoms is typical• Worsening of symptoms of asthmatics and those with chronic

pulmonary disorder– Evidence of association between asthma attacks and

atmospheric level of oxidants and sulfate• More frequent respiratory tract infections in areas with higher

air pollution levels• Cardiovasculat effects from atmospheric CO

– Reduces oxygen delivery to myocardium and may aggravate atherosclerosis

• Air pollution respiratory effects increase strain on heart in people with chronic bronchitis

• Mucosal irritation, nasal tickle, conjunctivitis• Eye irritation, esp. from particulates and photochemical

oxidants

Air Pollution and Cancer Risks

• Documented for community air pollution from point sources, such as smelters releasing arsenic (lung cancer)

• Radon air pollution of indoor air (lung cancer)• Work place exposure to asbestos and

mesothelioma of the lung• Central nervous system toxicity as learning

disabilities in children from airborne lead

WHO Air Quality Guidelines

• WHO has air quality guidelines– Represent widely agreed, contemporary

assessments of health effects of air pollution– Recommended targets for air quality at which the

health risks are significantly reduced. • Recommend reducing particulate matter (PM10)

pollution from 70 to 20 micrograms per cubic metre– Can reduce air quality related deaths by ca. 15%.

• Will help countries reduce the global burden of disease from respiratory infections, heart disease, and lung cancer.

WHO Guidelines - Air Quality and Health

• It is possible to derive quantitative relationships between air pollution levels and specific health outcomes (increased mortality or morbidity).

• Allows invaluable insights into the health improvements that could be expected if air pollution is reduced.

• Even relatively low concentrations of air pollutants have been related to a range of adverse health effects.

• Poor indoor air quality may pose a risk to the health of over half of the world’s population.

• In homes where biomass fuels and coal are used for cooking and heating, PM levels may be 10–50 times higher than the guideline values.

PM Guideline Values

• Aim: achieve the lowest concentrations possible • No threshold has been identified below which no health effect is

observed• Recommended value should represent an acceptable and

achievable objective to minimize health effects in the context of local constraints, capabilities and public health priorities.

• PM affects more people than any other pollutant. • Major components of PM are sulfate, nitrates, ammonia, sodium

chloride, carbon, mineral dust and water. • Complex mixture of solid & liquid particles of organic & inorganic

material. • PM2.5 (aerodynamic diameter smaller than 2.5 µm consodered

more dangerous– When inhaled, they may reach the peripheral regions of the

bronchioles, and interfere with gas exchange inside the lungs.

PM2.5 PM10

10 μg/m3 annual mean25 μg/m3 24-hour mean

20 μg/m3 annual mean50 μg/m3 24-hour mean

PM and Health Effects• Health health occur at exposure levels now experienced

by most urban and rural populations in both developed and developing countries.

• Chronic exposure contributes to risks of developing cardiovascular and respiratory diseases, as well as lung cancer.

• In developing countries: – Exposure from indoor combustion of solid fuels on open fires or

traditional stoves increases the risk of acute lower respiratory infections and associated mortality among young children;

– Indoor air pollution from solid fuel use is also a major risk factor for chronic obstructive pulmonary disease and lung cancer among adults.

• Mortality in cities with high levels of pollution exceeds that observed in relatively cleaner cities by 15–20%.

• In the EU, average life expectancy is 8.6 months lower due to exposure to PM2.5 produced by human activities.

PM and WHO Health Effects Guidance• Reducing particulate matter pollution from 70 to

20 micrograms per cubic metre as set out in the revised (2005) Guidelines, is estimated to reduce air quality related deaths by around 15%

• Reducing air pollution levels helps reduce the global burden of disease from:– respiratory infections– heart disease– lung cancer.

• Reducing the direct impact of air pollution will also reduce emissions of gases which contribute to climate change and provide other health and environmental benefits.

Ozone WHO Guidance• Guideline value: 100 μg/m3 8-hour mean • Definition and Principal Sources:• Ozone at ground level – not to be confused with

the ozone layer in the upper atmosphere – is a major constituents of photochemical smog.

• Formed by reaction of sunlight (photochemical reaction) with of pollutants such as:– Nitrogen oxides (NOx) from vehicle and industry

emissions– Volatile organic compounds (VOCs) emitted by

vehicles, solvents and industry.

• Highest levels occur during sunny weather.

Ozone Health Effects

• Excessive levels cause breathing problems, trigger asthma, reduce lung function and cause lung diseases.

• In Europe: currently one of the air pollutants of most concern.

• Studies report daily increases of: – 0.3% for mortality and– 0.4 % for heat disease

• per 10 µg/m3 increase in ozone exposure

NO2

• At short-term levels >200 μg/m3: a toxic gas causing significant inflammation of the airways.

• The main source of nitrate aerosols, which form an important fraction of PM2.5

• In the presence of ultraviolet light forms ozone. • The major anthropogenic emission sources are

combustion processes:– Heating– Power generation– Engines in vehicles and ships

40 μg/m3 annual mean

200 μg/m3 1-hour mean

NO2 Health Effects

• Epidemiological studies:– Increased symptoms of bronchitis in asthmatic

children associated with long-term exposure to NO2.

– Reduced lung function development linked to NO2 at concentrations currently measured (or observed) in cities of Europe and North America.

SO2

• Health effects associated with lower levels than previously believed. – Need for greater protection led to revised guideline values in 2002.

• Causality of health effects still uncertain, but reducing concentrations is likely to decrease exposure to co-pollutants

• Definition and principal sources:– A colourless gas with a sharp odour. – Produced from burning fossil fuels (coal and oil) and the smelting of

mineral ores that contain sulfur. – Main anthropogenic source is the burning of sulfur-containing fossil

fuels for domestic heating, power generation and motor vehicles

20 μg/m3 24-hour mean500 μg/m3 10-minute mean

SO2 Health Effects• Affects the respiratory system and the functions of the

lungs• causes irritation of the eyes. • Inflammation of the respiratory tract causes:

– Coughing– mucus secretion– aggravation of asthma– chronic bronchitis– Increased susceptibility to infections of the respiratory tract.

• Increased hospital admissions for cardiac disease and mortality increase on days with higher SO2 levels.

• When SO2 combines with water, it forms sulfuric acid– The main component of acid rain which is a cause of

deforestation.

UN Commission on Sustainable Development, 14UN Commission on Sustainable Development, 14thth SessionSession

Partnerships Fair, 2 May 2006Partnerships Fair, 2 May 2006

Eva RehfuessEva RehfuessProgramme on Indoor Air PollutionProgramme on Indoor Air Pollution

World Health OrganizationWorld Health Organization

Smoke in the Smoke in the KitchenKitchen

Health Impacts ofHealth Impacts ofIndoor Air PollutionIndoor Air Pollution

in Developing Countriesin Developing Countries

Prabir Mallik/The World Bank

• Some 3 billion people rely on solid Some 3 billion people rely on solid fuels (e.g. fuels (e.g. dung, wood, agricultural dung, wood, agricultural residues, charcoal, coal) for their residues, charcoal, coal) for their basic energy needs.basic energy needs.

• Cooking and heating with solid fuels Cooking and heating with solid fuels leads to high levels of leads to high levels of indoor smoke, indoor smoke, a complex mix of health-damaging a complex mix of health-damaging pollutants (including small particles, pollutants (including small particles, carbon monoxide, nitrogen oxides).carbon monoxide, nitrogen oxides).

• Typical small particle levels (PMTypical small particle levels (PM1010) in ) in biomass fuel-using home: 1000+ biomass fuel-using home: 1000+ µg/mµg/m33

European Union standard: 50 µg/mEuropean Union standard: 50 µg/m33

What is the problem?What is the problem?

Nigel Bruce/ITDG

WHO, Fuel for Life: Household Energy and Health

Who is most at risk?Who is most at risk?

Health outcome Evidence• ALRI (children <5yr)• COPD (adults)• Lung cancer (coal)

Between 10 - 20 studiesFew measured exposureConfounding problematic

• Tuberculosis• Cataract• Upper airway cancer• Asthma

Several consistent studies(more conflicting for asthma)

• Low birth weight• Perinatal mortality• Otitis media

Very few studies, support from environmental tobacco smoke and ambient air pollution studies

• Cardiovascular disease

No studies, but suggestive

What are the health impacts?What are the health impacts?

Smith, Mehta and Feuz, 2004

HighlyNeglected

Issue!

1.5 million annual deaths1.5 million annual deaths• in the poorest countriesin the poorest countries• > 800 000 among children> 800 000 among children• > 500 000 among women> 500 000 among women

Who is most affected?Who is most affected?

What is the link between indoor smoke What is the link between indoor smoke and the Millennium Development Goals?and the Millennium Development Goals?

Household Energy

MDG 1: Eradicate extreme poverty and hungerMDG 1: Eradicate extreme poverty and hunger

MDG 3: Promote gender equality and empower womenMDG 3: Promote gender equality and empower women

MDG 4: Reduce child mortalityMDG 4: Reduce child mortality

MDG 7: Ensure environmental sustainabilityMDG 7: Ensure environmental sustainability

"We will spare no effort to free our fellow men, women and children from the abject and dehumanizing conditions of extreme poverty, to which more than a billion of them are currently subjected."

United Nations Millennium Development Declaration, signed by all 191 Member States of the United Nations in September 2000

• Documenting the health burden of indoor air Documenting the health burden of indoor air pollution and household energypollution and household energye.g. assessment of the burden of diseasee.g. assessment of the burden of disease

What does the World Health What does the World Health Organization do?Organization do?

• Evaluating the effectiveness of technical solutions Evaluating the effectiveness of technical solutions and their implementationand their implementatione.g. catalogue of methods; regional training workshopse.g. catalogue of methods; regional training workshops

• Acting as the global advocate for health as a central Acting as the global advocate for health as a central component of international/national energy policiescomponent of international/national energy policiese.g. cost-benefit analysis of household energy interventions; e.g. cost-benefit analysis of household energy interventions; Ministerial side-event on household energy and healthMinisterial side-event on household energy and health

• Monitoring changes in household energy habits over Monitoring changes in household energy habits over timetimee.g. MDG indicator on solid fuel usee.g. MDG indicator on solid fuel use

4000 deaths a day from cooking fires?

Let's prevent them!

CSD-14, New York, Conference Room 2

11 May 2006, 6:15 pm – 7:45 pm