Green Plants Emit Pollutants Into Atmosphere As Temperature Increases, Study Shows

BUFFALO, N.Y. -- Contrary to a widely held belief among environmental scientists and the public, green plants do not cleanse the environment of atmospheric pollutants as efficiently as has been assumed, according to new research published recently in Atmospheric Environment.

The evidence is contained in a paper co-authored by Keri C. Hornbuckle, Ph.D., assistant professor of environmental engineering at the University at Buffalo, and Steven J. Eisenreich, Ph.D., chair of the Department of Environmental Sciences at Rutgers University.

The paper, describing work they conducted at the University of Minnesota, describes the atmospheric concentrations of more than 100 semivolatile organic compounds that exist in the environment as gases.

The researchers recorded for the first time how these compounds volatilize and adsorb to plants throughout each day.

The fieldwork was conducted in a remote, forested bog in Northern Minnesota, where the only surfaces were plant surfaces.

"Our work shows that plants can act as conductors, or temporary resting points, for atmospheric pollutants traveling around the globe," said Hornbuckle.

According to the data, rising atmospheric temperatures correlated with chemical emissions from the plants, while falling temperatures correlated with adsorption of chemicals to the plants.

"Our data show that plants are sources of these chemicals as much as they are sinks, or absorbers," said Hornbuckle.

"We always figured that because plant surfaces are waxy and lipid, that once the chemicals stuck to their leaves they would stay with the plants, and in a sense disappear from the environment," she said.

"But while plants do take these chemicals up, they don't do so as efficiently as we thought they did."

Hornbuckle explained that the finding will affect how scientists develop future models of concentrations of atmospheric pollutants.

The paper was published in the September issue of Atmospheric Environment.