How the kudzu invasion is poisoning the air with ozone

The fast-growing kudzu vine may be responsible for more toxic emissions of ozone than cars. Not only are these plants releasing chemicals into the air that harm humans, but they are spreading unchecked across the Eastern US.

Research published today in the Proceedings of the National Academy of Sciences shows that threats to the environment don't always come from humans. A release on the study explains:

Study co-author Manuel Lerdau, a University of Virginia professor of environmental sciences and biology. "This increase in ozone completely overcomes the reductions in ozone realized from automobile pollution control legislation."

Lerdau and his former graduate student, lead author Jonathan Hickman – now a postdoctoral fellow at Columbia University – used field studies at three sites in Georgia to determine the gas production of kudzu. They then worked with Shiliang Wu and Loretta Mickley, atmospheric scientists at Harvard University, who used atmospheric chemistry computer models to evaluate the potential 50-year effect of kudzu invasion on regional air quality.

"Essentially what we found is that this biological invasion has the capacity to degrade air quality, and in all likelihood over time lead to increases in air pollution, increases in health problems caused by that air pollution, and decreases in agricultural productivity," Lerdau said.

"This is yet another compelling reason to begin seriously combating this biological invasion. What was once considered a nuisance, and primarily of concern to ecologists and farmers, is now proving to be a potentially serious health threat."

So basically kudzu is belching out so much poison gas that the plants rival dry cleaners or trucks as the cause of air pollution. And now the weed, which is native to parts of Asia, spread across the Southern United States after being introduced there in the nineteenth century. Now it's reaching tentacles into the Eastern US.

In their paper, the researchers write:

In an extreme scenario, extensive kudzu invasion leads directly to an increase in the number of high ozone events (above 70 ppb) of up to 7 days each summer in some areas, up from 10 to 20 days in a control scenario with no kudzu invasion. These results establish a quantitative link between a biological invasion and ozone formation and suggest that in this extreme scenario, kudzu invasion can overcome some of the air quality benefits of legislative control.

via PNAS