Air Quality by City
A reference for 30 US metros — dominant pollutants, seasonal patterns, notable historical episodes, and the local agencies that publish data beyond the national AirNow feed. For real-time AQI on iPhone, install the free Smog Report app. Outside the US? See air quality around the world — London, Singapore, Delhi, Seoul, Sydney, Toronto, Paris and more.
New York, NY
Ozone (summer), PM2.5 (winter heating + occasional wildfire smoke transport).
Read →Los Angeles, CA
Ozone (year-round but worst June-October), PM2.5 (wildfire season).
Read →Chicago, IL
Ozone (summer), PM2.5 (industrial + transport).
Read →Dallas–Fort Worth, TX
Ozone (summer), PM2.5 (occasional Saharan dust + wildfire smoke transport).
Read →Houston, TX
Ozone (summer), PM2.5 (industrial + transport), HRVOCs (highly reactive VOCs from petrochemical plants).
Read →Atlanta, GA
Ozone (summer), PM2.5 (urban background + occasional wildfire smoke transport).
Read →Washington, DC
Ozone (summer), PM2.5 (urban + occasional wildfire smoke transport).
Read →Philadelphia, PA
Ozone (summer), PM2.5 (industrial + transport).
Read →Miami, FL
PM2.5 (Saharan dust June-August), ozone (mostly low), occasional red-tide aerosols.
Read →Phoenix, AZ
PM10 (dust + dust storms), ozone (summer), PM2.5 (winter inversions).
Read →Boston, MA
Ozone (summer), PM2.5 (transport + heating).
Read →Inland Empire (Riverside–San Bernardino), CA
Ozone (year-round, worst in summer), PM2.5 (wildfire season + winter inversions).
Read →San Francisco–Oakland, CA
PM2.5 (wildfire season — Aug-Oct), ozone (mostly low — fog and marine influence).
Read →Detroit, MI
PM2.5 (industrial + transport), ozone (summer).
Read →Seattle, WA
PM2.5 (wildfire smoke summer + winter wood smoke), low ozone year-round.
Read →Minneapolis–St. Paul, MN
PM2.5 (winter heating + wildfire smoke), ozone (summer).
Read →Tampa–St. Petersburg, FL
Ozone (spring-summer), PM2.5 (Saharan dust + Florida prescribed burns), red-tide aerosols.
Read →San Diego, CA
Ozone (summer-fall), PM2.5 (wildfire smoke autumn).
Read →Denver, CO
Ozone (summer — Front Range), PM2.5 (winter inversions + wildfire smoke).
Read →Baltimore, MD
Ozone (summer), PM2.5 (port + industrial).
Read →St. Louis, MO
Ozone (summer), PM2.5 (industrial + transport).
Read →Orlando, FL
Ozone (spring-summer), PM2.5 (Saharan dust + prescribed burns).
Read →Charlotte, NC
Ozone (summer), PM2.5 (industrial + occasional wildfire smoke transport).
Read →San Antonio, TX
Ozone (spring-summer), PM2.5 (Saharan dust + agricultural smoke).
Read →Portland, OR
PM2.5 (wildfire smoke summer + winter wood smoke), low ozone year-round.
Read →Salt Lake City, UT
PM2.5 (winter inversions — Dec-Feb), ozone (summer), windblown dust.
Read →Las Vegas, NV
PM10 (windblown dust + construction), ozone (summer).
Read →Bakersfield, CA
PM2.5 (winter — worst in US), ozone (summer — among worst in US), agricultural dust.
Read →Fresno, CA
PM2.5 (winter — among worst in US), ozone (summer — among worst in US), agricultural emissions.
Read →Pittsburgh, PA
PM2.5 (steel + coal legacy + topography), ozone (summer).
Read →Real-time AQI for any US city on iPhone
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