A Review by the Forum of International Respiratory Societies’ Environmental Committee

A Review by the Forum of International Respiratory Societies’ Environmental Committee

Part 1: The Damaging Effects of Air Pollution

According to a recent study published by the American College of CHEST Physicians, air pollution poses a great environmental risk to health. Outdoor fine particulate matter (particulate matter with an aerodynamic diameter < 2.5 μm) exposure is the fifth leading risk factor for death in the world, accounting for 4.2 million deaths and > 103 million disability-adjusted life years lost according to the Global Burden of Disease Report.

The World Health Organization attributes 3.8 million additional deaths to indoor air pollution. Air pollution can harm acutely, usually manifested by respiratory or cardiac symptoms, as well as chronically, potentially affecting every organ in the body. It can cause, complicate, or exacerbate many adverse health conditions. Tissue damage may result directly from pollutant toxicity because fine and ultrafine particles can gain access to organs, or indirectly through systemic inflammatory processes. Susceptibility is partly under genetic and epigenetic regulation. Although air pollution affects people of all regions, ages, and social groups, it is likely to cause greater illness in those with heavy exposure and greater susceptibility. Persons are more vulnerable to air pollution if they have other illnesses or less social support. Harmful effects occur on a continuum of dosage and even at levels below air quality standards previously considered to be safe.

PollutantInjury DeterminantsTissue Affected
Sulfur dioxideHighly solubleUpper airway and skin damage
Nitrogen dioxide


Carbon monoxide

Less soluble (nitrogen dioxide and ozone are irritating)Deeper lung penetration

Bronchial and bronchiolar injury

Carbon monoxide: tissue hypoxia

Particulate matter (PM10, PM2.5, PM0.1)Size, structure, and composition determine toxicityLarge particles: mucous membranes, upper airways

Small particles: bronchioles and alveoli

Ultrafine particles: systemic tissue reactions

PM0.1 = particulate matter with an aerodynamic diameter < 0.1 μm; PM2.5 = particulate matter with an aerodynamic diameter < 2.5 μm; PM10 = particulate matter with an aerodynamic diameter < 10 μm.

‘Doctors need to speak up’

Some have no idea air pollution affects the organs they specialize in, but it affects their organs too and they had better pay attention,” said Prof. Dean Schraufnagel, at the University of Illinois at Chicago.

“They need to educate their patients and then they should speak up” in favor of action.”

Researchers cannot experiment on people and so by necessity many studies show significant associations between poor air quality and disease, but cannot prove cause and effect.

However, Schraufnagel said particularly compelling evidence comes from three types of study: where air pollution and illness change in tandem over time, where the “dose” of pollution correlates with levels of disease and from animal studies.

For example, government action to slash pollution before the Beijing Olympics in 2008 led to a rise in birth weights in the city.

“Harmful effects occur even at levels below air quality standards previously considered to be safe,” warn the review scientists, who between them represent every continent. The good news is that the problem of air pollution can be addressed!

The best way to reduce exposure is to control it at its source,” said Schraufnagel. Most air pollution comes from burning fossil fuels to generate electricity, heat homes and power transport.

We need to work on these factors in a very dramatic way. “We are probably the first generation in history to be exposed to such a high level of pollution. People will say that in London or other places it was worse 100 years ago, but now we are talking about an incredible number of people exposed for a long time.”

We have megacities where all the citizens are breathing toxic air. “However, with all the tonnes of evidence we are collecting now, politicians will not be able to say we didn’t know.”

Where to go from here?

From walking more to reducing waste, here’s what you can do to make a difference

Most air pollution is produced by the burning of fossil fuels and waste, and this is the focus of the World Health Organization’s global recommendations

Prioritize walking, cycling, and public transport over cars in urban areas and shift to electric cars

Reduce the burning of stubble in fields upwind of cities

Create green spaces in cities to help remove some pollutants

In the UK, the government’s extensive research shows deterring polluting vehicles from city and town centers is by far the quickest, most cost-effective way to cut levels of nitrogen dioxide pollution, which are at illegal levels in most urban areas.

Other policies include:

Scrappage schemes for older, polluting vehicles and subsidies for electric vehicles can also help reduce pollution, although ministers have cut the latter

Policies such as cutting speed limits on polluted motorway sections, labeling pollution levels clearly on new cars and training people to drive more cleanly all had minimal impact

Best ways to avoid air pollution

The solution to air pollution is stopping it at source but until that happens, experts including the British Lung Foundation (BLF) suggest the following:

— Avoid spending long periods of time in places where pollution builds up, such as busy roads

— If you travel on foot or a bike, using backstreet routes away from congested roads can cut exposure by half. Even on busy streets, cyclists experience less pollution than drivers

— Some scientists recommend parents use covers on their buggies to protect infants

— Go to work earlier, before the rush hour has begun and levels of pollution have built up

— When air pollution is high and if you have a lung condition such as asthma, reduce or avoid strenuous outdoor exercise, or do your exercise inside

— There is very little evidence to recommend the use of face masks

If you want us to evaluate your community’s situation, contact us to get the latest reports and work with us to find the appropriate solutions.


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