Article: New trees cancel out air pollution cuts

[Guest guest]

Well, go figure .. this one was a surprise to me too!

 

*Smile*

Chris (list mom)

 

New Perfume Bottles In Stock

More Bottles & Pendants Coming Soon

http://www.alittleolfactory.com

 

~~~~~~~~~~~~~~~~~~~~~~~~~~~

 

http://www.newscientist.com/news/news.jsp?id=ns99996526

 

 

New trees cancel out air pollution cuts

 

 

19:00 13 October 04

 

 

 

 

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.

 

The researchers used the US Forest Service Industry Analysis, a database

of 250,000 randomly sampled forest plots around the country, and the

known VOC emission rate for each tree species for the study.

 

They calculated that vegetal sources of monoterpenes and isoprene rose

by up to 17% from the 1980s to the 1990s - equivalent to three times the

industrial reductions.

 

Farmland reverting to scrub, pine plantations and the invasive sweetgum

tree were behind most of the increases in the US.

 

Journal reference: Global Change Biology (vol 10, p 1737)

 

 

 

Anna Gosline