NEW YORK  - Living in a crowded city or near a busy highway may be tied to a higher chance of having a stroke or losing your memory, new research suggests.

A study published Monday in the Archives of Internal Medicine found a higher risk of stroke after “moderate” compared to “good” air quality days in Boston-area residents, especially when traffic-related pollution was high. And another report in the same journal documented a faster long-term decline in thinking and memory skills in women living in higher-pollution areas of the United States.

“One of the important points is that at levels that are considered to be generally safe by the US EPA (Environmental Protection Agency), we’re seeing important health effects,” said Gregory Wellenius, the lead author of the stroke study from Brown University in Providence. “Individuals that may be susceptible to air pollution health effects may consider staying inside during high air pollution levels,” Wellenius told Reuters Health.