Remember the anti-drug commercial where illicit drugs (played by butter) fried a brain (played by an egg)? Over the action, a gravelly voice intoned “This is drugs. This is your brain on drugs. Any questions?”

Those PSAs were a fixture of my childhood. Now, well into adulthood, I wonder if it is perhaps time for a redux. But in the sequel, instead of playing drugs, butter would play the part of dirty air.

Why the update, you ask? Because it turns out that over time, lungfuls of dirty air may affect our memories and even our moods.

This revelation comes from a neuroscience research team at Ohio State University, which published its findings this week in the journal Molecular Psychiatry (find it next to Rolling Stone at the local newsstand, or here). The research suggests that chronic exposure to soot—also known as fine particulate matter, or PM2.5—leads to inflammation in the hippocampus and cell connections therein that are both weaker and fewer. Such changes are connected to decreased learning and memory function, as well as depression.

The hippocampus sounds like an institute of higher learning for river horses (the literal translation of the Greek word “hippopotamus”), but it’s actually an incredibly important part of the brain. “We wanted to look carefully at the hippocampus because it is associated with learning, memory and depression,” said Laura Fonken, the study’s lead author.

Why does this matter to us? Well, soot is extremely common. It is generated wherever fossil fuels are burned, which means it’s billowing out of a tailpipe or smokestack nearby. According to the American Lung Association, more than 18.5 million people in the U.S. live in an area where the year-round levels of such pollution are unhealthy.

We’ve known for a long time that soot is bad for the lungs and the heart—not to mention a significant cause of premature death. But this latest research indicates it’s bad for our brains, too.

Fortunately, something can be done. Particle pollution is controlled by the Clean Air Act, and every five years, the Environmental Protection Agency is supposed to review the latest science and update air quality standards to ensure the public is adequately protected from breathing dangerous levels of the stuff. The time for EPA review is upon us; the agency should set as strong a standard as possible, and Earthjustice is working to ensure it does. The health reasons for doing so were already plentiful, but it seems these researchers at Ohio State may have added another one to the list.