A vine spreading its tendrils across the U.S. is being called a major contributor to ozone pollution by scientists.

Kudzu, a vine native to Japan and southeastern China, creates ozone through a chemical reaction between isoprene, nitric oxide and nitrogen in the air. Unlike atmospheric ozone, which protects the Earth from harmful ultraviolet radiation, ground level ozone is an air pollutant that can cause lung problems and prevents the growth of many kinds of plants.

Scientists at the University of Virginia and Columbia University studied the gas production of kudzu at three sites in Georgia. They then collaborated with atmospheric scientists at Harvard University to determine what affects the vine would have in the next 50 years on regional air quality.

"We found that this chemical reaction caused by kudzu leads to about a 50 per cent increase in the number of days each year in which ozone levels exceed what the Environmental Protection Agency deems as unhealthy," said study co-author Manuel Lerdau, a University of Virginia professor of environmental sciences and biology, in a release.

"This increase in ozone completely overcomes the reductions in ozone realized from automobile pollution control legislation."

The scientists believe that as the vine spreads — it's already made its way to Pennsylvania and New York — it will increase air pollution and reduce the growth of crop vegetation. It could also worsen lung diseases such as asthma and increase people's risk of developing lung cancer.

Kudzu can be kept in check through livestock grazing, mowing, burning and herbicide use.

The study is published in the May 17 issue of the Proceedings of the National Academy of Sciences.