Air Pollution and Respiratory Disease

Research conducted by NIEHS scientists has shown that long-term exposure to air pollutants increases the risk of respiratory illnesses such as allergies, asthma, chronic obstructive pulmonary disease, and lung cancer. Children and the elderly are particularly vulnerable to the health effects of ozone, fine particles, and other airborne toxicants. This research has resulted in the development of more stringent air quality standards that promote a higher quality of life, protect the health of children, the elderly and other vulnerable populations, and reduce the costs associated with respiratory disease. One of the first studies to establish a link between air pollution and respiratory health was the NIEHS-funded Six Cities Study, a long-term study on residents of six U.S. cities to assess the effects of common air pollutants on the risk of pulmonary and cardiovascular disease. The study results showed that people living in the more polluted cities had a higher risk of hospitalization and early death from lung cancer and other respiratory diseases than those living in the less polluted cities.

Recent data collected by NIEHS-funded scientists at the University of Southern California suggest that exposure to pollutants in vehicle and fossil fuel emissions may hinder lung development and limit breathing capacity for a lifetime. Their research shows that children who live in highly polluted communities are five times more likely to have clinically low lung function--less than 80% of the lung function normal for their age. Other studies conducted by the University of Southern California researchers indicate that increases in ground-level ozone, a highly reactive form of oxygen that is the primary component of urban smog, may actually cause asthma. Children who were active in outdoor sports in areas with high ozone concentrations were more than three times as likely to develop asthma as those who did not engage in outdoor sports during the five-year study. Air Pollution & Respiratory Disease: Estimated Reductions in Respiratory Illness Due to Enactment of Clear Skies ActLives saved by research on the health consequences of environmental pollutants can be counted in the millions. According to the Environmental Protection Agency’s estimates on air pollution, the commitment to new air quality standards and cleaner air will prevent 23,000 premature American deaths, 1.7 million cases of asthma attack or aggravation of chronic asthma, 67,000 new cases of acute and chronic bronchitis, 22,000 respiratory-related hospital admissions, and 42,000 hospital admissions for cardiovascular disease by the year 2010.

Other benefits of cleaner air, according to a study by NIEHS-funded researchers at the University of Washington, include 200 fewer cases of post neonatal mortality, 10,000 fewer infants of low birth weight, and 40,000 fewer emergency room visits for children by 2010. These findings demonstrate the impact that NIEHS-supported research and subsequent regulatory actions have had on protecting the health of our nation’s children and other vulnerable populations.

Air Pollution’s Effects A growing number of Americans are sniffling and suffering with allergies and asthma. Several studies have shown that air pollution and indoor allergens make asthma symptoms worse and can bring on an asthma attack. If you’re 1 of the 23 million Americans who suffer from asthma, you might get some relief by taking steps to reduce indoor allergen levels and modifying your lifestyle to avoid the ill effects of air pollution. Asthma is caused by swelling and inflammation of your airways. When the airways narrow, less air gets through to your lungs, causing wheezing, coughing, chest tightness and trouble breathing. Children with a family history of allergies and asthma are more likely to have asthma. Exposure to triggers in the environment, including allergens, pollutants and viral infections, also play a role. “The rapid increase in asthma cases from the late 1970s cannot be attributed to genetics alone,” says Dr. Peter Gergen, medical officer at NIH’s National Institute of Allergy and Infectious Diseases. “Changes in the environment, home surroundings and exposure to infections have also contributed to the prevalence of asthma.”

Understanding what makes asthma worse can help asthma sufferers keep their disease in check. NIH research has shown that children who live in inner cities are exposed to higher levels of allergens from dust mites, dogs, cats, rodents, cockroaches and mold in their homes. A recent study found that people with asthma and allergies may be able to alleviate asthma symptoms by reducing allergen levels in their homes. “Some simple measures--washing bedding in hot water, vacuuming and steam-cleaning, and using high-efficiency particulate air purifiers (HEPA) and mattress and pillow covers that do not allow allergens to pass through--can decrease the levels of household allergens,” Gergen says. But what if the air outside your home is filled with asthma triggers? A new 2-year study supported by NIH and the Environmental Protection Agency (EPA) showed that even modestly increased levels of air pollution cause more frequent asthma symptoms and lower lung function in children who have persistent asthma and live in inner city areas of the United States. Even air pollution levels within EPA’s safety standards made asthma worse in vulnerable children.

High levels of nitrogen dioxide, a component of motor vehicle emissions, had the greatest effect in the study, leading to many asthma-related school absences. Past research has also shown that ozone and particle pollution can affect asthma. Ozone, which is found in smog, is worse on hot days, especially in the afternoons and early evenings. Particle pollution, found in smoke and dust, is bad near busy roads and factories or when there’s smoke in the air. Researchers are studying different approaches to prevent and treat asthma. Asthma can’t be cured, but most people with asthma can control it and live active lives. Talk to your doctor about developing a plan to manage your asthma symptoms.

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