Try to find ways to reduce air emissions

Higher cancer risk due to toxic air exposure threatens about two million Americans, according to the latest National Air Toxics Assessment (NATA) report released by the U.S. Environmental Protection Agency (EPA).

The EPA report says that more than 2 million people live in areas where the cancer risk over a 70-year lifetime is greater than 100 in 1 million. The estimate comes from a county-by-county assessment of contaminants found in the air.

This risk level is unacceptable to EPA standards and requires corrective action. A risk level of between 10 in 1 million and 100 in 1 million usually triggers a deeper inquiry into the causes of the high pollution levels.

This assessment is based on air emissions for 2002. The last NATA used 1999 emissions inventory data. Between the two periods, the average cancer risk in the US actually went down from 41.5 in million in 1999 to 36.0 in 1 million. An assessment on 2005 data will be issued in late 2009 or early 2010.

The NATA assesses the relative concentrations in air of 181 types of pollutants, which have been proven to cause cancers, respiratory diseases and other health problems. In effect, the interpretation is that if 1 million people live for 70 years in an area with an air pollution mix identical to the 2002 (or whatever reference year) level, the probabilities are that 100 people are likely to develop cancer due to the long-term exposure.

Only 80 substances found in air are known to cause cancer. The carcinogen benzene accounts for about 30 percent of the overall cancer risk. Benzene is released into the air with the burning of fossil fuels, chiefly oil in automobile engines and coal in power plants.

Emissions from local industries constitute about 25 percent of the overall risk. Pollutants in the air without any identifiable emission sources make up the balance of 45 percent of overall cancer risk. These are known as “background” air toxics, and include carbon tetrachloride, arsenic compounds, methylene chloride and other compounds.

The states with large numbers of people exposed to high levels of toxic air are New York (862,012 people), California (445,781 people), Oregon (140,169 people), Washington (105,454 people) and Alabama (76,452 people).

Neighborhoods in Madison County, Ill., and Los Angeles, Calif., posted the highest risks for cancer — 1100 in 1 million for Madison County and 1200 in 1 million for L.A. Next to them were parts of Allegheny County, Pa., and Tuscaloosa County, Ala.

Neighborhoods in Coconino County, Ariz., and Lyon County, Nev., showed the lowest risks for cancer due to toxic air exposure. Kalawao County, Hawaii, and Golden Valley, Mont., had the lowest level of air toxics.

The risks of exposure to air toxics are local, which means they depend on the sources of emission nearest to you. Living and working in an areas with many industries and a lot of traffic, the cancer risk could go up to the 1000 in 1 million level or higher.

More details about the report may be obtained from http://www.epa.gov/nata2002.

Safety Tip:
• Work with your local air agency to find ways to reduce air emissions, if your area has high levels of toxic air.