Eye of Modok

A new study at the University of Colorado at Boulder shows that invisible, reactive gases hovering over the earth’s surface form the bulk of organic haze in both urban and rural areas around the world, not direct emissions of particulates as is commonly believed. The study shows that 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 research scientists believe that the extended source of particle pollution is reactive, colorless gases called Volatile Organic Compounds, or VOCs, the same gases that form smog. VOCs emitted in urban and regional areas immediately begin undergoing a chemical transformation that causes them to stick to particulate matter and increase pollution.

“What we’re seeing is that concentrations of secondary organic aerosols decrease little downwind from urban areas,” said assistant professor Jimenez from CU-Boulder’s chemistry and biochemistry department. “That tells us there has to be an extended source or continuous formation for the pollution. We think the gases react over a few days as the air travels downwind into more rural regions, producing more organic haze.”

VOCs include surface ozone, nitrogen compounds and sulfur dioxide. VOCs are released through emissions by cars and trucks, gasoline evaporation at gas stations during fill-ups, by paint thinners and dry cleaning solvents, as well as through some industrial processes. VOCs are also produced naturally by vegetation.

These past few smog filled hazy days in Beijing make me pine for clear blue skies and fresh air. However, there’s only 2 more weeks until we’re all off to Thailand for two weeks vacation!!

[tags] smog, pollution, environment, VOC, Beijing, Olympics [/tags]