AQI by Zip Code: Check Air Quality Near Me
How to check real-time AQI for any US zip code, plus typical air quality profiles for the 20 largest metro areas.
How to Check AQI by Zip Code
Four free tools give you real-time AQI for any US zip code:
- AirNow.gov — Type your zip code in the search bar. This is the official US government source, updated hourly from EPA regulatory monitors.
- EPA AQI app — Free iOS and Android app from the EPA. Tap your location or type a zip code for current and forecast AQI.
- IQAir — iqair.com or the IQAir app. Aggregates multiple data sources and shows real-time PM2.5 maps.
- Google search — Search "AQI [zip code]" or "air quality near me" for an instant card with the current AQI from your nearest monitor.
AQI Profiles: 20 Largest US Metro Areas
Typical AQI ranges based on historical monitoring data. Actual daily readings vary widely based on weather, wildfires, and local conditions.
| Metro | Typical AQI | Main Pollutant | Worst Season |
|---|---|---|---|
| Los Angeles, CA | 60-100 | Ozone, PM2.5 | Summer-Fall |
| Phoenix, AZ | 50-90 | Ozone, PM10 (dust) | Spring-Summer |
| Sacramento, CA | 55-100 | Ozone, wildfire PM2.5 | Summer |
| Denver, CO | 40-80 | Ozone | Summer |
| Fresno, CA | 55-105 | PM2.5, Ozone | Year-round |
| Chicago, IL | 35-70 | PM2.5 | Winter |
| Houston, TX | 45-85 | Ozone | Summer |
| Dallas, TX | 45-80 | Ozone | Summer |
| Salt Lake City, UT | 35-90 | PM2.5 (inversions) | Winter |
| Atlanta, GA | 35-65 | Ozone | Summer |
| New York, NY | 40-70 | PM2.5, Ozone | Summer |
| Seattle, WA | 30-60 (spikes during wildfire) | PM2.5 | Wildfire season |
| Portland, OR | 30-60 (spikes during wildfire) | PM2.5 | Wildfire season |
| San Francisco, CA | 30-60 (spikes during wildfire) | PM2.5 | Wildfire season |
| Miami, FL | 30-60 | Ozone, PM2.5 | Summer |
| Minneapolis, MN | 30-55 | PM2.5 | Winter |
| Cincinnati, OH | 40-70 | Ozone, PM2.5 | Summer |
| Pittsburgh, PA | 45-75 | PM2.5 | Year-round |
| Bakersfield, CA | 70-120 | PM2.5, Ozone | Year-round |
| El Paso, TX | 45-85 | Ozone, PM10 | Spring |
What to Do When AQI Is High in Your Area
When you check your local AQI and it is above 100, here are the steps to protect yourself:
- Close windows and doors. Keep outdoor air out until AQI drops below 100.
- Run your air purifier on a higher setting. HEPA purifiers filter PM2.5 from indoor air. Check the CADR matches your room size.
- Avoid vigorous outdoor exercise. During high AQI, physical exertion increases the amount of polluted air you breathe in.
- Check on sensitive family members. Children, elderly, and those with asthma or heart conditions are most vulnerable.
- Monitor throughout the day. AQI can improve significantly by evening as temperatures drop and ozone dissipates.
At AQI 151 and above, everyone should limit outdoor time. At 201 and above, stay indoors with purifiers running and wear an N95 mask if you must go outside.
Wildfire note: Cities in the Pacific Northwest and California can see AQI jump from below 50 to above 200 within a single afternoon when regional wildfires intensify or winds shift. AQI forecasts during fire season can be unreliable for extended periods. Check AirNow.gov on the day of any outdoor activity during fire season.
Frequently Asked Questions
How often does AQI data update?
AirNow.gov updates AQI data hourly from official regulatory monitoring stations. PurpleAir community sensors update every 2 minutes. State air quality agencies also publish hourly updates. Weather apps and Google's AQI widget typically pull from official sources and reflect hourly updates with a short delay.
Is the AQI the same across a whole city?
No. AQI is measured at specific monitoring stations. A large city may have several official stations, and readings can differ by 20-40 AQI points between them. A station in a park will show different readings than one near a freeway. PurpleAir's community sensor network provides hyperlocal data that shows how much AQI can vary within a few city blocks.
Why is my AQI high when it looks clear outside?
Visual clarity is not a reliable indicator of air quality. Fine particles (PM2.5) that cause elevated AQI are invisible to the naked eye. Ozone, which is also measured in AQI, is a colorless gas. You can have an AQI above 100 from ozone or fine particles on a day that looks perfectly clear. Conversely, visible haze from coarser dust can look bad but may produce a lower PM2.5-based AQI than invisible fine particle pollution.
What is the worst city for air quality in the US?
Bakersfield, California consistently ranks among the worst in the US for both PM2.5 and ozone, due to its location in the San Joaquin Valley, surrounding agricultural activity, and topography that traps pollutants. Fresno and Visalia are also in the top tier of worst annual PM2.5 cities. Los Angeles leads in ozone days. Rankings vary by year and which pollutant is measured. The American Lung Association publishes annual State of the Air rankings.