OZONE FACT SHEET
Ozone (O3) is a highly reactive gas that is a form of oxygen. It results primarily from the action of sunlight on hydrocarbon vapors and nitrogen oxides emitted in fuel combustion. Ozone reacts chemically ("oxidizes") with internal body tissues that it comes in contact with, such as those in the lung. It also reacts with other materials such as rubber compounds, breaking them down.
· Ozone acts as a powerful respiratory irritant at the levels frequently found in most of the nation's urban areas during summer months. Ozone exposure may lead to:
- shortness of breath
- chest pain when inhaling deeply
- wheezing and coughing
· Long-term, repeated exposure to high levels of ozone may lead to reductions in lung function, inflammation of the lung lining and increased respiratory discomfort.
· Exposure to elevated levels of ozone greatly increases the risk of asthma attacks, need for medical treatment and for hospitalization in persons with asthma.
· The EPA estimates that five to 20 percent of the total U.S. population is especially susceptible to the harmful effects of ozone air pollution. Five groups of people are at particular risk:
- people with pre-existing respiratory disease; those already afflicted with lung disease such as asthma, chronic bronchitis and emphysema
- senior citizens
- people who work or exercise outdoors
- “responders”—otherwise healthy individuals who are more susceptible to ozone exposure
- children, because their airways are smaller, their respiratory defenses are not fully formed, and their higher breathing rates increase their exposure
· Ozone levels typically rise between May and October when higher temperatures, an increased amount of sunlight, and stagnant atmospheric conditions promote transformation of air pollutants into ozone.
· For almost two decades prior to 1997, the federal air quality standard for ozone had been 0.12 parts per million (ppm) averaged over one hour, but tests carried out on healthy adults and children undergoing moderate exercise while exposed to lower levels of ozone showed a decrease in subjects’ breathing ability.
· In response to a lawsuit filed by the American Lung Association, the U.S. Environmental Protection Agency in July 1997 set a more protective ozone standard of 0.08 ppm averaged over an eight-hour period. Compliance is based on the fourth highest reading per year averaged over three years.
· The EPA will designate ozone nonattainment areas for the new 8-hour standard by April 15, 2004, a date agreed to after another legal action by the American Lung Association in 2002. Designations will be based on the data from the latest three-year period, expected to be 2001-2003. Based on 1999-2001 monitoring data, 291 counties have average ozone concentrations that exceed the standard.
· EPA has not formally reviewed scientific research on ozone since 1996, although the Clean Air Act requires such reviews every five years. The American Lung Association began legal action in December 2002, to require the Agency to schedule formal reviews. The legal action is still pending.
· To reduce ozone air pollution, the American Lung Association supports stringent controls on motor vehicles and commercial and industrial sources of the hydrocarbon compounds and nitrogen oxide emissions. These controls include:
- stricter pollution control requirements for power plants, including those that will bring older power plants up to current emissions standards
- stronger pollution control requirements for new motor vehicles and small engines
- cleaner fuel standards, including diesel
- cleaner diesel vehicles, especially heavy equipment and other diesel engines
- improved in-use performance of existing pollution control equipment
· The ground-level ozone in the lower atmosphere (troposphere) should not be confused with the natural protective layer of ozone in the upper atmosphere (stratosphere). Although both are made of the same molecules (ozone), the ozone in the upper atmosphere protects us from the sun’s harmful ultraviolet rays, while the ozone in the lower atmosphere harms us.
For more information, call the American Lung Association at 1-800-LUNG-USA (1-800-586-8722), or visit our web site at http://www.lungusa.org.
The American Lung Association has been fighting lung disease for nearly 100 years. With the generous support of the public and the help of volunteers, we have seen many advances against lung disease. However, our work is not finished. As we look forward to our second century, we will continue to strive to make breathing easier for everyone through programs of education, community service, advocacy, and research. The American Lung Association’s activities are supported by donations to Christmas Seals® and other voluntary contributions. You may obtain additional information via the American Lung Association Web site at http://www.lungusa.org.
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