Short-term exposure to air pollution, defined as occurring within five days of the stroke, can significantly increase the risk of stroke, according to a new study.

In the study, researchers from University of Jordan in Amman looked at pollutants such as nitrogen dioxide, ozone, carbon monoxide and sulphur dioxide as well as different sizes of particulate matter, including PM1, which is air pollution that is less than 1 micron (μm) in diameter, as well as PM2.5 and PM10.