Between 1999 and 2003, levels of suspended particles in the air have decreased in the United States: to 10% for fine particles of less than 2,5 microns in diameter (PM2,5) - the most dangerous to health - and 7 % for those with less than 10 microns (PM10).
On 25 years, these declines even reach the 30%, according to estimates by the Environmental Protection Agency (EPA), which publishes this week an inventory of particulate pollution across the territory (http://www.epa.gov/airtrends/).
But if the overall trend is positive, local situations appear very variable. The Los Angeles area, for example, California remains the most polluted in the country despite significant progress. While in the Northeast, PM2,5 rates have increased due to auto and industrial emissions. According to the EPA, the improvements noted in the Southeast and Midwest would be largely the Acid Rain Program of the fruit that has reduced to 33 1990 and 2003% in emissions of sulfur dioxide from power plants.
The agency also hopes that the implementation of the Clean Air Diesel Rule Nonroad, specifying the standards of fine particles, and the finalization of the Clean Air Interstate Rule will strengthen the results so far. Environmental movements meanwhile, while welcoming the government report, denouncing the repeated delays in the adoption of stricter rules, especially in the energy sector.
LAT 15 / 12 / 04 (US registers drop in levels of fine-particle pollution) http://www.latimes.com/