Clean Air Home Lab

How to Check AQI by Zip Code

Where to find today's air quality for any US zip code, and what to do when the number is high.

Last updated October 2026

This page does not have a live lookup. To see today's AQI for your zip code, go to AirNow.gov and type your zip code in the search box.

How to Check AQI by Zip Code

These free tools show the AQI for your area:

What the Number Means

EPA uses six color bands. 0 to 50 is Good (green). 51 to 100 is Moderate (yellow). 101 to 150 is Unhealthy for Sensitive Groups (orange). 151 to 200 is Unhealthy (red). 201 to 300 is Very Unhealthy (purple). 301 and higher is Hazardous (maroon).

See the full table, with what each level means, on our What Is AQI? page.

What to Do When AQI Is High in Your Area

EPA says that above 100, air is unhealthy: first for sensitive groups, then for everyone as the number climbs. These steps follow EPA's advice:

Want to know what is in the air inside your home? See the best air quality monitors.

Wildfire note: AirNow says smoke can travel a long distance from a fire. During smoke, use the AirNow Fire and Smoke Map, which includes sensor data that updates more often than official monitors.

This page points you to EPA's tools and repeats EPA's advice. It is not medical advice. If you have a health condition, ask your doctor what to do on bad air days.

Frequently Asked Questions

How often does AQI data update?

EPA says AirNow uses hourly readings from air quality monitors to report current air quality, using a method called the NowCast. Because air quality changes during the day, you can expect the current AQI to change too. The official daily AQI takes a full 24 hours of data, so it reports yesterday.

Is the AQI the same across a whole city?

Not always. AQI comes from monitors at set places. EPA says that during smoke, particle levels can vary a lot over small distances and short times, so monitors in the same area may show different categories. The AirNow Fire and Smoke Map adds sensor readings, which update more often.

Why is my AQI high when it looks clear outside?

EPA says some particles are big or dark enough to see, but others are so small they can only be seen with an electron microscope. Ozone is a gas. So the air can look clear and still have a high AQI. It also works the other way: EPA notes that haze is sometimes just high humidity, not pollution.

What is the worst city for air quality in the US?

The American Lung Association ranks US cities each year in its State of the Air report. It keeps separate lists for ozone, year-round particle pollution and short-term particle pollution, ranked by the number of unhealthy air days. A city can rank high on one list and not appear on another. Check lung.org for the current lists.

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Sources and last review

Specifications on this page are taken from the documents below, on the dates shown. We do not physically test products; read our methodology. Page last reviewed .