Air pollution is not only a visual nuisance -- it significantly impacts public health. The World Health Organization (WHO) estimates that 7 million people die each year as a result of excessive exposure to polluted indoor and outdoor air. Specific to the U.S., 47 percent of people live in counties where air quality is considered unhealthy.
Among different types of pollutants, ozone and particulate matter -- the tiny, airborne particles of chemicals, soil, dust, smoke or allergens -- have the greatest impact on health, and contribute to several conditions involving the respiratory and cardiovascular systems.
Acute Respiratory Disease
Exposure to polluted air triggers inflammation and irritation in the lungs, increases susceptibility to infection, and promotes changes to lung function -- and these effects can incrementally worsen with more exposure time and higher pollution levels. Also, the health consequences of poor air quality tend to be more pronounced in children, pregnant women, older adults and anyone who already has heart or lung disease.
But even healthy people can experience coughing, throat irritation, chest tightness, headaches and shortness of breath when exposed to heavily polluted air. In addition, respiratory illnesses such as colds, bronchitis or pneumonia, which is an infection in one or both lungs, are more likely to occur with repeated exposure to polluted indoor or outdoor air.
Chronic Respiratory Disease
Air pollution is also related to asthma, a condition in which the airways swell, narrow and produce extra mucus, making it difficult to breathe. Exposure to polluted air not only worsens asthma and increases asthma-related hospitalization rates, but also plays a role in the development of this respiratory condition.
Polluted air also aggravates chronic obstructive pulmonary disease (COPD), an inflammatory lung disease characterized by persistent, obstructed flow of air in the lungs which interferes with breathing. COPD produces a variety of symptoms, including cough, mucus production, breathing difficulty and wheezing. Although COPD is most commonly associated with smoking, this condition is worsened by polluted indoor and outdoor air.
While cigarette smoking is the most notable cause of lung cancer, environmental and occupational exposure to polluted air also increases the risk of this lung disease. In fact, in 2013, the WHO's International Agency for Research on Cancer concluded that outdoor air pollution is a carcinogen, or cancer-causing substance, and that particulate matter is closely linked to lung cancer occurrence rates.
Lung cancer is characterized by the uncontrolled growth of abnormal cells in one or both lungs, which over time can progress to the development of tumors and impair the ability of the lungs to supply the blood and body with oxygen. Over time, the cancer growth can destroy lung tissue, increase infection risk and spread to other parts of the body.
Heart Disease and Stroke
Exposure to air pollution also increases the risk of heart disease and stroke. A decade-long study demonstrated a direct link between air pollution and atherosclerosis, which is the narrowing or blockage of arteries caused by plaque buildup.
Another 10-year study published in the August 2016 issue of Lancet provided more clues to this relationship. Researchers found that long-term exposure to pollution, notably particulate matter and nitrogen oxides, can accelerate the buildup of calcium in the coronary artery, worsen inflammation and prematurely age blood vessels -- all factors that make heart attack and stroke more likely.
Take steps to keep indoor air clean, by reducing -- or avoiding -- the use of wood-burning stoves and fireplaces. Do not smoke or allow others to smoke in your home. Thoroughly vacuum or clean floors regularly and minimize the use of chemicals in the home. Stay informed of air quality updates in your community, and take precautions to reduce your exposure to unhealthy levels of ozone and particle pollution. Avoid exercising near high-traffic areas. Also, do not exercise outdoors and minimize outdoor activities on high pollution days.
Air pollution can severely impact health, and can lead to premature death since it reduces lung function, increases infection and cancer risk, and worsens health in those with heart or lung disease. If you have cardiovascular or respiratory disease, or if you are pregnant or care for young children, talk to your doctor about additional ways to protect yourself and your family when the air quality is poor.
Reviewed by Kay Peck, MPH RD
- American Lung Association: State of the Air 2014
- World Health Organization: Household Air Pollution and Health
- World Health Organization: Air Pollution
- World Health Organization: Ambient (Outdoor) Air Quality and Health
- The Lancet: Estimates and 25-Year Trends of the Global Burden of Disease Attributable to Ambient Air Pollution: An Analysis of Data From the Global Burden of Diseases Study 2015
- Current Opinion in Pulmonary Medicine: Pulmonary Health Effects of Air Pollution
- Environmental Protection Agency: Linking Air Pollution and Heart Disease
- Global Heart: Advances in Understanding Air Pollution and Cardiovascular Diseases: The Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air)
- Lancet: Association Between Air Pollution and Coronary Artery Calcification Within Six Metropolitan Areas in the USA (the Multi-Ethnic Study of Atherosclerosis and Air Pollution): A Longitudinal Cohort Study