Kids: Stay away from the road.

The closer children live to roads, the higher their risk of allergy and atopic diseases. That’s the finding of the German Research Center for Environment and Health at the Institute of Epidemiology in Munich, Germany.

After studying about 2,900 4-year-olds and more than 3,000 6-year-olds, researchers found that kids living closest to major roads have a 50 percent greater risk for allergies.

The study used controls to rule out other explanations like parent allergy history, pets, number of siblings, and socioeconomics.

“[Children] living very close to a major road are likely to be exposed not only to a higher amount of traffic-derived particles and gases, but also to more freshly emitted aerosols, which may be more toxic,” wrote the study’s lead author, Joachim Heinrich, Ph.D. He said that children living closer than 50 meters (164 feet) to a busy street had the greatest chances of getting allergic symptoms.