Besides elevating crime, that might also bring about a serious decline in mental health. A March 2019 study even showed that teenagers exposed to toxic, polluted air are at a higher risk of psychotic episodes, such as hearing voices or paranoia. Lead researcher Joanne Newbury, from King’s College London, says she cannot yet claim that her results are causal, but the findings are in line with other studies suggesting a link between air pollution and mental health. “It does add to evidence linking air pollution to physical health problems and air pollution link to dementia. If it’s bad for the body, it’s to be expected that it’s bad for the brain,” she says.