Thousands Urged to Stay Indoors Across Arizona and California

Residents in parts of Southern California and Arizona have been advised to remain indoors as unhealthy air pollution levels spread across the region, according to an interactive map from AirNow.

Los Angeles, Phoenix Hit by Unhealthy Particle Pollution
The maps show fine particle pollution reaching the “unhealthy” range on the Air Quality Index in many areas of Los Angeles and Phoenix. Elevated levels of PM2.5 — tiny inhalable particles measuring about 2.5 micrometers, roughly 30 times smaller than the width of a human hair — have been detected across much of Southern California and Arizona.

When air quality falls into the unhealthy category, the Environmental Protection Agency recommends that sensitive groups avoid prolonged or strenuous outdoor activity and consider moving activities indoors. For the general public, the EPA advises reducing long or intense outdoor exertion and taking more frequent breaks when outside.

Understanding the EPA Air Quality Index
The Air Quality Index measures pollution on a scale from 0 to 301 and higher:

0–50 (Good): Air quality is satisfactory and poses little or no risk.
51–100 (Moderate): Air quality is acceptable, though some unusually sensitive individuals may experience effects.
101–150 (Unhealthy for sensitive groups): Sensitive groups may experience health effects, while the general public is less likely to be affected.
151–200 (Unhealthy): Some members of the general public may experience health effects, and sensitive groups may face more serious impacts.
201–300 (Very unhealthy): Health alert conditions, with increased risk for everyone.
301 and higher (Hazardous): Emergency conditions where everyone is more likely to be affected.

Los Angeles recorded readings well above 100, while Phoenix saw levels reach the mid-200s earlier Monday morning before dropping back into the unhealthy range.

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