Monday, October 18, 2004

Trees causing pollution!

Think this little study will make it onto the CBS evening news? It's one of those perverse man bites dog type of stories... I've got my fingers crossed, how about you?

Industry has dramatically cut its emissions of pollutants, called volatile organic compounds. But those cuts have been more than offset by the amount of VOCs churned out by trees.

The revelation challenges the notion that planting trees is a good way to clean up the atmosphere.

When fossil fuels used in industry and automobiles fail to combust completely, they generate VOCs, which react with nitrogen oxides and sunlight to form poisonous ozone in the lower atmosphere. In the past few decades, the introduction of more efficient engines and catalytic converters has dramatically reduced these emissions.

But trees also produce VOCs, which tend to be ignored by scientists modelling the effects of ozone on pollution. So a team led by Drew Purves at Princeton University investigated the impact of newly planted forests on VOC levels in the US. newscientist.com

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