By nature, filters lose some degree of efficiency after prolonged exposure to air pollution. The rate at which your mask may lose efficiency will depend on the level of particle pollution it is exposed to, the number of hours it is worn, and the rate of breathing (e.g., the mask will filter pollution more intensively when breathing heavily during exercise than during rest).

Related news

View all

Wildfire Map Spotlight: South Fork Fire, Nebraska

A large fire in western Nebraska is triggering evacuations and evacuation warnings. Learn more…

Read more

June 16, 2026: Delhi among top 10 most polluted cities in the world

Delhi records AQI above 170, ranking among the world's most polluted cities. Pre-monsoon dust and…

Read more

How desertification reshapes the planet

The earth’s changing climate is creating more desert, and with its accompanying dust, more health…

Read more