Researchers are reporting that outdoor and indoor air pollution plays a role in nearly one-third of strokes around the world. The findings are based on an analysis of global trends in 188 countries from 1990 to 2013.

Though unclear, researchers believe particles from fuel combustion and other sources cause irritation and inflammation in blood cells after the particles enter the lungs. These pollutants eventually increase disease in the arteries, causing plaque buildup and narrowing of the arteries.

There are many risk factors for stroke, including high BMI, high blood pressure and sugar, high sodium intake, smoking, air and household pollutants, as well as a diet low in fruits and veggies.

The good news is that most of these factors can be modified with lifestyle changes, leading doctors to believe about ¾ of all strokes could be prevented.