Air pollution is a big problem. It's our single largest environmental health risk, and causes an eighth of all global deaths worldwide.

We know that air pollution increases respiratory diseases and the risk of infections like pneumonia. But now, new research suggests air pollution may alter the properties of bacteria themselves, in some potentially worrying ways.

This month, we spoke to Dr Julie Morrissey from the University of Leicester about the study, and what it means for our health.

Image credit: Wisconsin Department of Natural Resources / Flickr