A recent study suggests that breathing dirty air takes a heavy toll on gut bacteria boosting risk of obesity diabetes gastrointestinal disorders and other chronic illnesses. The study published online in the journal Environment International found that young adults exposed to higher levels of ozone showing less microbial diversity and more of certain species associated with obesity and disease. We know from previous research that air pollutants can have a whole host of adverse health effects. The takeaway from this paper is that some of those effects might be due to changes in the gut said senior author Tanya Alderete an assistant