A regional air quality alert was issued for much of Southern California as harmful levels of fine particle pollution spread ...

The Air Quality Index is used nationwide to measure the severity of air pollution and categorize the health risks that are involved with various levels of pollution. ... (purple): 201 to 300 ; ...

The EPA's Air Quality Index can tell you whether breathing outside air can hurt you. ... Purple indicates very unhealthy air (151-200) Maroon indicates hazardous air (301 plus).

The national average air quality index in 2023 was 38, according to IQAir, a Swiss air quality technology company. More than 100 nations had cleaner air , on average, than the United States, and ...

The EPA's Air Quality Index can tell you whether breathing outside air can hurt you. ... Purple indicates very unhealthy air (151-200) Maroon indicates hazardous air (301 plus).

The Southwest Ohio Air Quality Agency reports that "levels of ozone within the region may approach or exceed unhealthy ...

The U.S. has one of the world’s most advanced systems to monitor air pollutants. Can it keep up with a changing climate?

Air quality is measured by the Air Quality Index, or AQI. The index was created by the Environmental Protection Agency in 1999. When the AQI exceeds 50, air quality alerts, or AQAs, are issued.

Air quality alerts are issued when the air quality index is forecast to reach an unhealthy level, which includes forecasts in the orange, red, purple, and maroon categories.

Some popular weather apps had reported a dangerously hazardous Air Quality Index. By Amy Graff Amy Graff is a reporter on The Times’s weather team. Readings from several popular weather apps had ...