Emission of Smog Ingredients from Trees Is Increasing Rapidly

Changes in U.S. forests caused by land use practices may have inadvertently worsened ozone pollution, according to a study led by Princeton University scientists. The study may help explain why ozone levels have not improved in some parts of the country as much as was anticipated with the enactment of clean-air laws. Environmental technologies such as catalytic converters and hoses that collect fumes at gas pumps have substantially reduced human-produced volatile organic compounds (VOCs). However, in some parts of the country — particularly the area extending from Alabama up through the Tennessee Valley and Virginia — these improvements may have been outweighed by increased VOC emissions from forests, mainly because of tree growth in abandoned farmland and increases in plantation forestry. For more information visit: http://www.princeton.edu/pr/news/04/q3/0927-trees.htm.