Study finds the insect epidemic may increase ambient levels of VOCs
By Bob Berwyn
SUMMIT COUNTY — As if millions of acres of dead forests aren’t enough, the waves of bark beetles spreading across the West may also be contributing to increased air pollution in the region.
A new study shows the insects can make trees release up to 20 times more of certain organic substances that foster haze and air pollution in forested areas. The gases, classified as volatile organic compounds — meant to be a defense against the beetles — are released from the beetles’ bore holes.
VOCs are known to contribute to smog and haze that obscures views of natural landscapes in U.S. national parks and other natural areas where tourists flock in summer. The haze may in turn harm human health, reduce visibility and affect climate.
The study was led by Kara Huff Hartz of Southern Illinois University Carbondale, Gannet Hallar of the Desert Research Institute’s Storm Peak Laboratory in Steamboat Spring.
“These results highlight one of the many potential feedbacks due to aerosols, which continue to be the greatest challenge to improving predictive models for air quality, visibility and climate,” said Alex Pszenny, program director in the National Science Foundation’s Division of Atmospheric and Geospace Sciences, which funded the research.
To determine how beetle attacks affect the atmosphere, the researchers measured VOC levels in the air near healthy and infected pine trees. They found that beetle-infested trees release up to 20 times more VOCs than healthy trees near the ground surface. The predominant type of VOC released by trees is called ß-phellandrene.
A paper reporting the findings appeared this week in the journal Environmental Science & Technology, published by the American Chemical Society.
Other authors of the paper are Hardik Amin and Aaron Brown of Southern Illinois University Carbondale; P. Tyson Atkins of the Desert Research Institute; Rachel Russo of the University of New Hampshire; and Barkley Sive of Appalachian State University in Boone, N.C.