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Unformatted text preview: MOTOR VEHICLE AIR POLLUTION AND PUBLIC HEALTH: ASTHMA AND OTHER RESPIRATORY EFFECTS Asthma in the United States Asthma is a widespread, chronic lung disease in which the airways are inflamed and respond to stimuli such as allergens, cold air, irritant chemicals and air pollution by narrowing. This narrowing of the airways can result in significant difficulties in breathing (asthma attacks) requiring medication, and if sufficiently severe can result in the need for physician attention, hospital admission and even death. Approximately 15 million persons in the United States are estimated to have asthma, resulting in over 1.5 million emergency department visits, about 500,000 hospitalizations, and over 5,500 deaths each year 1 . An estimated 10.5 million Americans (including 3.8 million children < age18) had an asthma attack or episode in 1999. Asthma also accounts for an estimated 3 million lost workdays in adults and 10.1 million lost school days in children each year. The estimated total cost related to asthma is $12.7 billion in $2000, with $8.1 billion in direct costs and $4.6 in indirect costs. 2 Overall asthma prevalence has increased dramatically over the past two decades, rising 75 percent between 1980 and the average in 1993-4. While the highest prevalence of asthma is in children ages 5 to 14, the greatest increase in asthma prevalence has occurred in children ages 0 to 4 which increased 160 percent over the 15-year period 3 . More recent data suggests that overall asthma mortality and morbidity may be leveling, though a change in 1997 in the way asthma health statistics are collected makes it too early to determine if this represents a long-term trend. What remains clear is that asthma disproportionately affects the Black population, with asthma prevalence rates that are more than 21 percent higher than whites 4 . Motor Vehicle Air Pollution and Asthma An extensive body of scientific studies spanning at least three decades has documented the link between air pollution and negative health impacts on people with asthma, including asthma attacks. The pollutants most clearly identified as associated worsening the health of people with asthma and with asthma attacks are sulfur dioxide, ozone and particulate matter 5 6 . More recently, a small but growing body of scientific evidence suggests that air pollution may play a role in the development of asthma 7 and impairs long-term lung development 8 , with a primary focus on motor vehicle-related air pollution. Motor vehicles are a significant source of the volatile organic hydrocarbons and nitrogen oxides that combine in the presence of heat and sunlight to form ground-level ozone, contributing approximately 25 and 33 percent respectively of the nations total in 2000. In addition, while direct motor vehicles emissions are a relatively small contributor to the nations overall emissions of particulate matter (PM 10 and PM 2.5 ), heavy-duty trucks and buses and off-road construction equipment are a significant source of exposure to particulate matter in urban areas. When equipment are a significant source of exposure to particulate matter in urban areas....
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This note was uploaded on 04/03/2008 for the course BIOL 101 taught by Professor Smith during the Spring '07 term at Iowa State.

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