EPA has posted information on the Internet estimating outdoor concentrations of 32 air toxics nationwide.
Air toxics are those pollutants known or suspected of causing cancer or other serious health problems, such as birth defects.
This posting represents the first phase of EPA''s National-Scale Air Toxics Assessment, a detailed look at 32 common air toxics identified as posing the greatest potential risks to public health in urban areas.
The information released does not estimate human exposure or health risks -- EPA is developing those estimate for release in early 2001.
This first phase of the assessment includes estimated emissions from industries and other facilities in 1996 and estimated concentrations in the outdoor air.
In the next phase of the assessment, EPA will develop estimates of the amount of toxics people breathe and the resultant health risk.
EPA will submit these estimates to scientific peer review later this year.
The assessment is different from the agency''s Toxic Release Inventory (TRI), a program comprising annual industry-generated estimates of air, water and waste emissions.
For example, today''s assessment includes data on toxic air emissions from on-road vehicles, which the TRI does not.
The Clean Air Act Amendments of 1990 require EPA to regulate toxic air pollution by industry.
To date, the agency has issued 46 regulations for 82 different types of major industrial sources, such as chemical plants, oil refineries, aerospace manufacturers and steel mills.
EPA expects these standards, combined with its rules for smaller industries, to reduce yearly emissions of air toxics by 1.5 million tons from 1990 levels.
In addition, EPA as issued a suite of motor vehicle and fuels regulations, including tailpipe emission standards for cars, SUVs, mini-vans, pickup and heavy trucks and buses; standards for cleaner-burning gasoline; a natural low-emission vehicle program; and the recently proposed standards for low-sulfur diesel fuel.
These requirements are expected to reduce, by the year 2020, emissions of a number of air toxics from on-road motor vehicles by at least 75 percent from 1990 levels, according to EPA.
The agency plans to update the assessment every three years to help measure the nation''s progress in reducing public health risks from air toxics.
The information posted is available at www.epa.gov/ttn/uatw/nata.
by Virginia Sutcliffe