U.S. gains in air quality are slowing down
Study indicates challenges of meeting ozone goals
After decades of progress in cleaning up air quality, U.S. improvements for two key air pollutants have slowed significantly in recent years, new research concludes. The unexpected finding indicates that it may be more difficult than previously realized for the nation to achieve its goal of decreased ozone pollution, scientists said.
"Although our air is healthier than it used to be in the 80s and 90s, air quality in the U.S. is not progressing as quickly as we thought," said National Center for Atmospheric Research (NCAR) scientist Helen Worden, a co-author. "The gains are starting to slow down."
The study, was produced by an international team of researchers, including three from Â鶹Ãâ·Ñ°æÏÂÔØBoulder: mechanical engineering associate professor Daven Henze, mechanical engineering PhD student Zhen Qu, and Brian McDonald, a research scientist at the Cooperative Institute for Research in Environmental Sciences.
The research analyzed extensive satellite and ground-based measurements of nitrogen oxides and carbon monoxide. They found that levels of pollutants that can contribute to the formation of ground-level ozone, or smog, have failed to continue a fairly steady decline as estimated by the U.S. Environmental Protection Agency.
"We were surprised by the discrepancy between the estimates of emissions and the actual measurements of pollutants in the atmosphere," added Zhe Jiang, the lead author of the study. "These results show that meeting future air quality standards for ozone pollution will be more challenging than previously thought."
Jiang, who conducted much of the research during a postdoctoral fellowship at NCAR, is now with the University of Science and Technology of China.
