Robbie Girling, an associate professor of agroecology, and other researchers at the UK Centre for Ecology & Hydrology at the University of Reading and the University of Birmingham discovered that air pollutants can confuse pollinators that use odors to navigate and move around and communicate. A study they published in Environmental Pollution shows that ozone and diesel exhaust significantly reduce the presence of pollinators, the number of times pollinators visit plants and how many seeds the plants produce. James Ryalls, one of the authors of the study, says, “Some bugs might get the first sniff when chemical compounds from a flower land on their antennae. They then follow that odor plume like a treasure map back to the plant.”

After feeding, Girling says insects such as honeybees learn which compounds lead to the tastiest flowers and return to them. But ozone and diesel exhaust can muddy those perfumes. “The [pollutants] can degrade the signal that they use, so they might not be able to find the flower anymore. Insects are under a lot of pressure at the moment from human influence, and when you start to push at things from all different directions, at some point, they can’t stand up to it. And they collapse.”