The study, published in Inhalation Toxicology, looked at healthy non-smoking men and women between ages 18 to 35 and predominantly of normal weight.

The researchers from the National Institute of Environmental Health Sciences, the University of North Carolina at Chapel Hill and the U.S. Environmental Protection Agency found the ozone effect on lung function was lowest for underweight people -- BMI less than 18.5 -- and greatest in overweight individuals -- BMI above 25.

"It has been known for a long time that in response to short-term exposure to ozone lung function tends to temporarily drop in many people. There has recently been interest in why some people's lung function drops more than others -- age and perhaps genetics, as well as diet may play a role," study co-author Dr. Stephanie London, of the NIEHS, said in a statement.

"We were intrigued by recent mouse studies that showed that obesity increases lung responses to ozone and wanted to see whether this applied in humans."

Ozone is chemical pollutant generated by a reaction between nitrogen oxides, volatile organic compounds and oxygen in the presence of sunlight.