Invisible gasses form most organic haze

BOULDER, Colo., July 10 (UPI) -- A U.S. study suggests invisible, reactive gases, not direct emissions of particulates, form the bulk of organic haze observed around the world.

Many science and health professionals have believed sources spewing soot and other tiny particles directly into the air were the primary culprit in the formation of organic haze. But a study at the University of Colorado-Boulder's Cooperative Institute for Research in Environmental Sciences shows aerosols formed chemically in the air account for about two-thirds of the total organic haze in urban areas and more than 90 percent of organic haze in rural areas.

The study was led by Qi Zhang, a former CIRES scientist now at the Atmospheric Sciences Research Center at the State University of New York-Albany and CIRES researcher Jose-Luis Jimenez.

The research -- which included scientists at the University of Manchester in England, the Paul Sherrer Institute in Villigen, Switzerland, the National Institute for Environmental Studies in Tsukuba, Japan, and the U.S. National Oceanic and Atmospheric Administration's Earth System Research Laboratory in Boulder -- appears in the online edition of the journal Geophysical Research Letters.