Smoke plumes emanating from wildfires are swept high up into the air and spread over thousands of kilometers even days after a fire has been put out. The fine particles and harmful ozone contained in these plumes often have devastating effects on the air quality of US cities and consequently the health of their inhabitants. This is according to Alexandra Larsen of North Carolina State University in the US who led the first ever study taking a long-term look into the effects that wildfire smoke has on air quality across the US. The article appears in the Journal of Exposure Science and Environmental Epidemiology which is published by Springer Nature.