Researchers pinpoint how trees play role in smog production

April 25, 2013
Image: Wikipedia.

After years of scientific uncertainty and speculation, researchers at the University of North Carolina at Chapel Hill show exactly how trees help create one of society's predominant environmental and health concerns: air pollution.

It has long been known that trees produce and emit isoprene, an abundant molecule in the air known to protect leaves from oxygen damage and . However, in 2004, researchers, contrary to popular assumptions, revealed that isoprene was likely involved in the production of particulate matter, that can get lodged in lungs, lead to lung cancer and asthma, and damage other tissues, not to mention the environment.

But exactly how was anybody's guess.

Jason Surratt, assistant professor of environmental sciences and engineering at the Gillings School of Global Public Health, now reveals one mechanism by which isoprene contributes to the production of these tiny, potentially health-damaging particles.

The study found that isoprene, once it is chemically altered via exposure to the sun, reacts with man-made to create particulate matter. Nitrogen oxides are pollutants created by cars, trucks, aircrafts, and other large scale sources.

"The work presents a dramatic new wrinkle in the arguments for reducing man-made pollutants worldwide," said Surratt, whose work was published this month in the Proceedings of the National Academy of Sciences. "Isoprene evolved to protect trees and plants, but because of the presence of nitrogen oxides, it is involved in producing this negative effect on health and the environment."

"We certainly can't cut down all the trees," Surratt adds, "but we can work on reducing these man-made emissions to cut down the production of fine particulate matter."

With the precise mechanism now revealed, researchers can plug it into air quality models for better predicting episodes of and potential effects on earth's climate. The advance would allow researchers and environmental agencies to evaluate and make regulatory decisions that impact public health and climate change.

"We observe nature's quirks, but we must always consider that our actions do have repercussions," said Surratt. "It's the interaction between these natural and man-made emissions that produces this air pollution, smog and – and now we know one reason for how it happens."

Explore further: Research shows isoprene from biofuel plants likely to lead to ozone deaths

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1.5 / 5 (8) Apr 25, 2013
After all the lies told by "environmentalists" I give this zero (give or take) credibility.
3 / 5 (8) Apr 25, 2013
After all the lies told by "environmentalists" I give this zero (give or take) credibility.

And exactly what "lies" would they be? Things that you don't agree with?
1.9 / 5 (9) Apr 26, 2013
After all the lies told by "environmentalists" I give this zero (give or take) credibility.

And exactly what "lies" would they be? Things that you don't agree with?

That would be my guess.
1 / 5 (1) May 07, 2013
Isoprene is fine up to when strides in our evolution provided NOx.
1 / 5 (2) May 07, 2013
Further reading:

Here an excerpt from the Introduction only

@Sean W
You might be interested in the following to uphold your 0 'creditability' assertion.
If you adhere to one of your past presidents statements quoted in the intro.

It surprises most people to learn that plants emit much more hydrocarbon into the atmosphere than that coming from human activities, especially during extended warm weather (Purves et al., 2004), when hydrocarbon inputs into the atmosphere can be especially deleterious (Monson and Holland, 2001; Purves et al., 2004). This fact is behind the famous quote of Ronald Reagan that 'approximately 80 % of our air pollution stems from hydrocarbons released by vegetation' (Pope, 1980). The large amount of hydrocarbon coming from plants was used to suggest that air pollution control was not needed, quoting further: 'so let's not go overboard in setting and enforcing tough emission standards from man-made sources'. "

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