# AirNow: How to Read the Air Quality Index and Plan Your Day

- Published: Jul 16, 2026
- Source (HTML): https://selfcarecorp.com/articles/airnow-how-to-read-the-air-quality-index-and-plan-your-day.html
- Published by: [Self Care Corp](https://selfcarecorp.com/)

> AirNow, the EPA's free service at airnow.gov, reports a 0-500 Air Quality Index in six colors. Here's how to read it and plan your outdoor time.

AirNow is the free, official U.S. air quality service at [airnow.gov](https://www.airnow.gov/), run by the Environmental Protection Agency (EPA) with several partner agencies. Type in your ZIP code and it shows your local Air Quality Index, or AQI: a score from 0 to 500, sorted into six color-coded categories, that tells you how clean or polluted the outdoor air is right now. The self-care version is short. Check the color before you plan a run, a long walk, or an afternoon in the yard, and ease off outdoor time as the number climbs past 100. As of July 2026, AirNow says the same readings are available through its free mobile app on the Apple and Android app stores.

This guide is for everyday readers in the United States who want one simple habit for checking air quality. It uses the U.S. AQI and focuses on planning your day, not on medical advice or diagnosis. If you live with a health condition, your own doctor's guidance comes first.

## What is AirNow, and who runs it?

AirNow is a government air quality service, not a private app or a single backyard sensor. According to AirNow's About page, it is a partnership of the U.S. EPA, the National Oceanic and Atmospheric Administration (NOAA), the National Park Service, NASA, the Centers for Disease Control and Prevention (CDC), and tribal, state, and local air quality agencies. Those agencies feed real monitor readings into one place, so you get a local number without hunting across a dozen websites.

To use it, open [airnow.gov](https://www.airnow.gov/), enter your ZIP code, and read the current AQI for your area. That is the whole starting step. Everything below is just learning to read what the number is telling you.

## What the AQI numbers actually mean

The AQI is the EPA's scale for reporting daily air quality. According to the EPA, it runs from 0 to 500, and the higher the number, the more polluted the air and the greater the health concern. A reading near 100 roughly matches the level of the national air quality standard the EPA sets to protect public health, which makes 100 the rough line where 'acceptable' starts tipping toward 'unhealthy.'

The EPA builds the AQI from five common pollutants: ground-level ozone, particle pollution (tiny bits of dust, soot, and smoke measured as PM2.5 and PM10), carbon monoxide, sulfur dioxide, and nitrogen dioxide. On any given day, your local AQI reflects whichever of these is worst. Here is how the EPA groups the values:

| AQI | Category | Color | What it generally means |
| --- | --- | --- | --- |
| 0-50 | Good | Green | Air quality is satisfactory |
| 51-100 | Moderate | Yellow | Acceptable, with a small risk for some people |
| 101-150 | Unhealthy for Sensitive Groups | Orange | Sensitive groups may feel effects |
| 151-200 | Unhealthy | Red | Some of the general public may feel effects |
| 201-300 | Very Unhealthy | Purple | Health alert; risk rises for everyone |
| 301+ | Hazardous | Maroon | Emergency conditions for everyone |

## When should I cut back on time outside?

Watch the number 100, and you have most of what you need. The EPA notes that AQI values at or below 100 are generally considered satisfactory, and that above 100 the air turns unhealthy first for sensitive groups and then for everyone as the value keeps rising. The EPA counts people with heart or lung conditions, older adults, children and teens, and anyone who is very active outdoors among those more sensitive to air pollution.

Green and yellow days are usually fine for a normal walk or workout. On an orange day (101-150), someone in a sensitive group might shorten a hard outdoor session or move it indoors. On red days (151-200) and higher, it is reasonable for most people to keep outdoor activity gentle and brief. None of this means you have to stop moving; it just means choosing where and how hard. If steady heart care is part of why you track this, the calm, everyday routines in our guide to [everyday heart-care habits](https://selfcarecorp.com/articles/aortic-dissection-and-arteriosclerosis-everyday-heart-care-habits.html) sit nicely alongside a daily air check.

## Checking air quality during wildfire smoke

Smoke can push the AQI up quickly, and AirNow has a tool made for exactly that. The EPA, working with the U.S. Forest Service, runs the AirNow Fire and Smoke Map at [fire.airnow.gov](https://fire.airnow.gov/). According to AirNow, the map blends readings from permanent PM2.5 monitors with thousands of lower-cost, crowdsourced sensors, so you can see smoke conditions closer to your own street than a single regional station would show.

PM2.5 is fine particle pollution: specks small enough to travel deep into your lungs, and the main worry in wildfire smoke. On a smoky day, the practical moves are simple. Keep windows and doors closed, run your air conditioner or air cleaner on recirculate if you have one, and save errands and outdoor exercise for hours when the map shows lower numbers. When the AQI is high, staying indoors is the easier call.

## Turn it into a two-minute daily habit

The point of AirNow is not to memorize pollutant charts. It is to make one quick check part of your morning, the same way you glance at the weather. A small routine keeps it effortless:

- Bookmark [airnow.gov](https://www.airnow.gov/) or download the free AirNow app so the number is one tap away.
- Enter your ZIP code once so it remembers your area.
- Read the color, not just the digits: green or yellow, carry on; orange or higher, adjust the plan.
- Attach the check to something you already do, like your first coffee or lacing up your shoes.
- On poor-air days, swap the outdoor plan for an indoor one instead of skipping movement altogether.

Pairing an air check with other small outdoor habits, like the timing tweaks in our look at [lowering your mosquito risk](https://selfcarecorp.com/articles/west-nile-virus-simple-habits-to-lower-your-mosquito-risk.html), makes 'check before I head out' feel automatic. Clean-air days are a quiet gift, and a two-minute look at AirNow helps you spend more of them outside and take it easy on the days the air asks you to.

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