Frequently Asked Questions

Although it acts as a protective layer high above the earth, ground-level ozone can be harmful to breathe. Ozone is the prime ingredient of smog; it is not emitted directly into the air but rather is formed by gases called nitrogen oxides (NOx) and volatile organic compounds (VOCs). In the presence of strong sunlight, these gases react with oxygen in the air to form ozone concentrations that can remain high over large regions.

Certain urban areas tend to have high ozone levels. However, areas downwind of urban settings are also subject to high ozone exposure, as winds carry VOCs and NOx from their original sources. The process of ozone traveling to these downwind areas is referred to as ozone transport. It is especially significant in certain areas of the eastern United States, including the "northeast corridor" (roughly, from Washington, D.C. to Boston) and the vicinity of Lake Michigan.

In these areas, transport of ozone to downwind areas, even across state boundaries, can contribute to local ozone pollution problems.

Why is ground-level ozone a problem?

Ground-level ozone can be harmful to people and the environment. Levels above the health-based standards established by the U.S. Environmental Protection Agency (EPA) are known to cause chest pain, coughing, throat irritation, and congestion, and may also worsen bronchitis, heart disease, emphysema, and asthma. Healthy people as well as those with respiratory problems experience breathing problems when exposed to ozone. EPA has established a health-based standard for ozone to protect people from negative respiratory effects.

Approximately 64 million people live in areas where ozone levels are greater than the maximum health standard. Ground-level ozone also reduces growth rates in plants by interfering with the production and storage of starches.

At certain concentrations, ozone can damage the quality and harvest yield of crops such as corn, wheat, and soybeans. Ground-level ozone also reduces the ability of trees and plants to fight disease. EPA estimates an agricultural crop loss of $2 billion to $3 billion dollars per year attributable to ozone exposure; the extent of forest damage is currently being studied.

What is being done about the problem?

The Clean Air Act of 1990 requires that EPA and individual states and cities work cooperatively to reduce emissions of VOCs and NOx from cars, fuels, industrial and chemical facilities, power plants, consumer and commercial products, and other sources.

Cleaner cars and fuels, new kinds of gasoline nozzles, enhanced vehicle inspection, and other programs will be phased in over the next decade.

What is OTAG and what are its goals?

The Ozone Transport Assessment Group (OTAG) is a partnership among EPA, the Environmental Council of the States (ECOS), and various industry and environmental groups.

ECOS is a national organization of environmental commissioners with members from 50 states and territories. The goal of this partnership is to develop a thoughtful assessment and a consensus agreement for reducing ground-level ozone and the pollutants that cause ground-level ozone.

OTAG explicitly addresses ozone transport over the eastern United States.

What action is OTAG taking to address the problem?

No individual state or regional jurisdiction can be expected to either fully assess or subsequently resolve all of the issues relevant to the long-range transport of ground-level ozone.

To foster thoughtful assessment and development of consensus solutions to this problem, EPA and ECOS formed OTAG to bring together all interested states and other relevant stakeholders, such as industry and environmental groups.

OTAG's primary objective is to collectively assess ozone transport and to develop a strategy for reducing ozone pollution on a regional scale. OTAG is scheduled to present its finding and strategy to EPA in fiscal year 1997.

Where is more information available?

For more information on OTAG, please contact Ryan Schnare, Communications Coordinator for the OTAG Outreach and Communications Subgroup, at (703) 218-1411, or via E-mail at: rschnare@walcoff.com.

Information may also be found on the following Web sites:

OTAG Air Quality Assessment Workgroup