CU-Boulder study suggests air quality regulations miss key pollutants

A new study led by the University of Colorado at Boulder reveals that air quality regulations may not effectively target a large source of fine, organic particle pollutants that contribute to hazy skies and poor air quality over the Los Angeles region.

According to the study, a much smaller percentage of organic haze than was previously thought is directly emitted by vehicles and industrial processes. Instead, 75 percent of fine, organic particle pollutants form when reactive gases called VOCs, or volatile organic compounds, are oxidized and condense onto existing particles in the air.

"Air quality regulations today effectively target most sources of 'primary,' or directly emitted particles," said lead author Ken Docherty, a researcher with the university's Cooperative Institute for Research in Environmental Sciences. "Yet our study indicates that the 'secondary,' or chemically formed particles contribute more significantly to poor air quality, even in very polluted urban regions.