The EPA's Air Quality Index can tell you whether breathing outside air can hurt you. How to read the scale.

Add Yahoo as a preferred source to see more of our stories on Google. The air quality in Detroit is unhealthy Friday with some areas in southeast Michigan even experiencing very unhealthy or hazardous ...

Add Yahoo as a preferred source to see more of our stories on Google. The AQI is measured on a scale from 0 to 500, with the lower the number, the healthier the air. (Getty Creative) But many ...

Delhi residents woke up to an alarming air quality crisis on Tuesday, just a day after Diwali celebrations. Thick smog and toxic air have pushed the city’s pollution levels into the ‘Very Poor’ to ...