The health effects of air pollution

The health effects of air pollution on humans are many, and widespread across Earth. Respiratory and cardiovascular effects of air pollution have long been recognised, and account for the majority of air pollution-related deaths. There is also a strong link between poor air quality and the incidence of lung cancer.

Globally, ambient (outdoor) air pollution causes an estimated 25 per cent of all adult deaths from heart disease, 24 per cent from stroke, 43 per cent from chronic obstructive pulmonary disease and 29 per cent from lung cancer. Household (indoor) air pollution also leads to a wide variety of similar diseases and is one of the top five causes for premature death across the world. Current estimates put the death toll from household and ambient air pollution combined at 7 million deaths a year.

A person cooks using open fires. — Air pollution from repeated exposure to sources such as open fires causes a range of health issues affecting the respiratory and circulatory systems, among others. Image adapted from: Quang Nguyen Vinh via Pexels

Pollutants such as particulate matter, ozone (O₃), nitrogen dioxide (NO₂) and sulfur dioxide (SO₂) are some of the larger public concerns for health.

Harm from particulate matter occurs when very fine particles such as dust, aerosols from fuel emissions or soot reach the alveoli (air sacs) in the lungs and enter the bloodstream and cause inflammation affecting other organs in the body, particularly the heart, blood vessels and brain.

Current estimates put the death toll from household and ambient air pollution combined at 7 million deaths a year.

Other health complications associated with both short- and long-term exposure to air pollution include diabetes, premature birth, low birth weight, and, possibly, dementia.

Ground-level ozone, produced from the interaction of many different pollutants in the presence of sunlight, can cause chest tightness or breathlessness in some people, including those with pre-existing asthma. Other gases, such as sulfur dioxide and nitrogen dioxide have similar effects.

Who is affected by air pollution?

Air pollution affects everyone but there are some groups—babies and young children, the elderly, and those living in poverty or who are disadvantaged—that are more susceptible to its adverse effects than others.

Five children smiling — Children are more vulnerable to the risks of air pollution than healthy adults. Image adapted from: Loren Joseph via Unsplash; CC0

Children may be more vulnerable due to their developing lungs, increased time spent outdoors, and their susceptibility to colds and flu. If pregnant women are exposed to air pollution it can also affect the growth of the foetus. The elderly often have other health complaints, including chronic lung disease, that may make them susceptible to the adverse effects of exposure to air pollution.

Many of the world’s poor and disadvantaged live in conditions that increase their exposure to air pollution. Living in slums, close to public transport or industrial areas, or in dwellings without proper ventilation or sanitation can result in inhabitants inhaling much higher levels of air pollution than their more economically well-off neighbours. Around 90 per cent of deaths from ambient air pollution occur in low- and middle-income countries.

Globally, we are achieving progress. Almost half of cities in high-income countries that are monitoring air pollution reduced their levels by 5 per cent between 2008 and 2013. During this time in low- and middle-income nations that are monitoring air pollution, almost a third have reduced their levels by 5 per cent as well. This means that lives are already being saved, but there is still a long way to go.

No level of pollutants in the air is deemed safe.