HOUSTON (March 27, 2014) National efforts in the last decade to clear the air of dangerous particulate matter have been so successful that most urban areas have already attained the next benchmark, according to new research by Rice University.
Atmospheric researchers at Rice studied the state implementation plans (SIPs) from 23 regions mandated by the Environmental Protection Agency to reduce particulate matter (PM) smaller than 2.5 microns (PM 2.5) to less than 15 micrograms per cubic meter by 2009.
The Rice analysis appears this week in the Journal of the Air and Waste Management Association.
All but one of the regions studied reported they had met the goal by deadline. States with regions that met the deadline included Connecticut, Georgia, Illinois, Indiana, Kentucky, Maryland, Michigan, Missouri, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Tennessee and West Virginia, as well as the District of Columbia. The final region, Alabama, reported attainment in 2010.
PM 2.5 concentrations in the nonattainment regions that filed SIPs to attain the standard by 2009 declined by an average 2.6 micrograms per cubic meter significantly greater improvement than in regions that had attained the standard from its inception. The study showed PM reductions in the SIP regions were broadly spread, rather than pinpointed at the most polluted monitors.
"One of the things we were most interested in looking at was to see if states were cherry-picking their measures to meet the standard by reducing pollution at their worst monitors, compared with how much they were doing to bring down levels all across the region so that people were breathing cleaner air," said Daniel Cohan, an associate professor of civil and environmental engineering at Rice.
"It was encouraging to find that across the country, we have seen overall particulate-matter levels come down. We found very slight extra improvement at mon
|Contact: David Ruth|