Air pollution may be a vector for superbugs, according to a new study that suggests a link between the two for the first time and raises the possibility that curbing smog could reduce antibiotic resistance globally.

A peer-reviewed study published in The Lancet Planetary Health on Monday found that antibiotic resistance increases in tandem with levels of small particulate matter, or PM2.5, which originates from engine combustion and can penetrate the lungs and bloodstream.

“The association has strengthened over time, with changes in PM2.5 levels leading to larger increases in antibiotic resistance in more recent years,” the researchers said. Especially high levels of both small particulate matter and antibiotic resistance were found in north Africa, the Middle East and south Asia.