The Environment - Air Pollution And Asthma

Asthma is a chronic lung disease characterized by the narrowing or blockage of the air passages aggravated by "triggers" in the air. The effects are shortness of breath, wheezing, chest tightness, and coughing. Long term effects include weakening of the heart muscle. In some cases, emergency room treatment is needed to restore normal breathing. In 2002, 17 million people in the U.S. had asthma; 5 million were children under age 18. In 1980, a total of 6.7 million had the disease. In 1999, over 4,600 people died of asthma, down from a high of 5,667 in 1996, but nearly twice the number that died in 1980.

What are the triggers of asthma? Cold air, allergens, and some types of viral infections. Those with asthma are also sensitive to air pollutants. In high concentrations, these pollutants can cause an asthma attack. The graphic shows the self-reported prevalence rate of asthma per 1,000 people³. From 1980 to 1996, the number of asthma cases rose dramatically. In 1997, the prevalence rate data was changed to exclude anyone that hasn't had an attack in the past 12 months. Therefore, the numbers drop significantly from 1996 to 1997, suggesting that many asthmatics have their condition under control.

Part of the drop from 1997 to 1999 may have to do with the drop in the amount of air pollutant emissions and, therefore, the reduction in at least one of the triggers for asthma. Another reason could be that more people are seeking treatment to control the disease. The rate of physician office visits for asthma was up 52.5% from 1980 to 1999. The rate of emergency room visits was up also, but not as much: 29%. Some of the downturn in active asthma cases, recently, may also be due to government programs that encourage management of the disease. In 1997, the National Asthma Education and Prevention Program outlined new guidelines for the treatment of asthma in an attempt to reduce the number of deaths and disabilities. In 1999, the Centers for Disease Control and Prevention (CDC) developed the National Asthma Control Program. Its goals are to "reduce the number of deaths, hospitalizations, emergency department visits, school or work days missed, and limitations on activity due to asthma."⁴ In 2001, the CDC received $25.7 million in funding for the project, which was spent on collecting and analyzing data, implementing scientifically-proven treatments for asthma, and partnerships with state and local health departments.

Who develops asthma? Doctors don't know why some people develop asthma and others do not. Two risk factors are heredity and a disposition to allergies. Some have claimed that air pollution causes (not just triggers) asthma. How can this be when pollution levels were down (29% between 1980 and 1996), and rates of asthma were up (78%)? Some studies have shown a correlation between air pollution and childhood asthma. A study conducted by the University of Southern California followed 3,535 children living in 12 communities from 1993 to 1998. Six communities had higher than average ozone concentrations and six had lower than average ozone concentrations. The study found that children who played three or more sports (physical activity requiring the intake of more than the "normal" amount of air) in high ozone communities developed asthma at a rate 3 times higher than athletic children in low ozone communities. Another study conducted over 8 years (the results were released in January 2002) found that children who moved to communities with high levels of particulate matter (PM-10), nitrogen dioxide, and acid vapor showed decreased lung function growth compared to children who moved to communities with low levels of these pollutants. As seen previously, emissions of PM-10 and nitrogen oxides (nitrogen dioxide is one form) are increasing. Does this mean we are putting more children at risk for serious health problems?

Sources: Mannino, David M., et. al. Centers for Disease Control and Prevention. "Surveillance for Asthma -- United States, 1960-1995." Morbidity and Mortality Weekly Report, April 24, 1998. David M. Mannino, et. al. Centers for Disease Control and Prevention. "Surveillance for Asthma -- United States, 1980-1999." Morbidity and Mortality Weekly Report, March 29, 2002. Office of Air Quality Planning and Standards. U.S. Environmental Protection Agency. National Air Pollutant Emissions Trends, 1900-1998, March 2000. Retrieved July 2, 2002 from http://www.epa.gov/ttn/chief/trends/trends98/trends98.pdf. The Asthma and Allergy Foundation of America. "Asthma & Allergies." Retrieved July 3, 2002 from http://www.aafa.org. The Asthma and Allergy Foundation of America and the National Pharmaceutical Council. A Closer Look at Asthma. Retrieved July 3, 2002 from http://www.aafa.org. Centers for Disease Control and Prevention. "National Asthma Control Program." Retrieved July 3, 2002 from http://www.cdc.org. "Study Links Air Pollution and Asthma." SinusPharmacy, February 1, 2002. Retrieved July 3, 2002 from http://www.sinuspharmacy.com/news_childrenasthmastudy.html. U.S. Census Bureau. Statistical Abstract of the United States, 2001.