Short answer. Check U.S. air quality on AirNow.gov, the home of EPA's Air Quality Index (AQI), and on its Fire and Smoke Map during wildfires 12. The AQI runs in six color-coded categories: 0 to 50 is good, and above 100 the air is unhealthy, first for sensitive groups, then for everyone 1. In wildfire smoke, Ready.gov advises an N95 mask or a closed room with a portable air cleaner 4.
Where can I check air quality right now?
On AirNow.gov, run by EPA: search your location for current and forecast AQI 1. When wildfires burn, use the AirNow Fire and Smoke Map to see smoke near you 2. To be notified of air quality forecasts, sign up to EnviroFlash, a partnership between EPA and state or local air quality agencies; not every agency takes part 3. Ready.gov also tells you to pay attention to air quality alerts 4.
What do the index levels mean?
EPA's AQI has six categories 1:
| Color | Level | AQI | What it means |
|---|---|---|---|
| Green | Good | 0-50 | Little or no risk |
| Yellow | Moderate | 51-100 | Acceptable; some risk for people unusually sensitive to air pollution |
| Orange | Unhealthy for Sensitive Groups | 101-150 | Sensitive groups may have health effects |
| Red | Unhealthy | 151-200 | Some of the public may have effects; sensitive groups more serious ones |
| Purple | Very Unhealthy | 201-300 | Health alert: risk increased for everyone |
| Maroon | Hazardous | 301 and higher | Health warning of emergency conditions |
An AQI of 100 generally matches the national short-term air quality standard 1. The index covers five pollutants: ground-level ozone, particle pollution (PM2.5 and PM10), carbon monoxide, sulfur dioxide and nitrogen dioxide 1. See what an air quality index means.
How polluted is the air on average?
Close to, but above, World Health Organization guidelines. The median U.S. city had about 8 µg/m³ of fine particles (PM2.5) a year in 2021-2023 5, against a WHO guideline of 5 7. For nitrogen dioxide, the regional background was about 10.5 µg/m³ 6, against a WHO guideline of 10 7. That NO2 figure is a regional background over roughly 80 km: a busy street is higher.
What should I do during wildfire smoke or a bad air day?
Ready.gov's wildfire advice 4:
- before fire season, store an N95 mask if available;
- use an N95 mask, or choose a room to close off from outside air and run a portable air cleaner or filter in it;
- use high-efficiency filters in central air conditioning; if it takes in fresh air, set it to "recirculate" and close the outdoor intake damper;
- if you are not ordered to evacuate but it is smoky, stay inside in a safe location or go to a community building where smoke levels are lower;
- people with asthma, COPD or other lung conditions should take precautions where air quality is poor.
Evacuate immediately if authorities tell you to 4. Our guides cover wildfire smoke, masks for smoke, a clean-air room, ozone days, dust storms, people most at risk and children. For official alert channels, see U.S. alerts.
Frequently asked questions
What AQI is unhealthy?
101 to 150 is unhealthy for sensitive groups, 151 to 200 is unhealthy, 201 to 300 is very unhealthy and 301 or more is hazardous 1.
Where do I see wildfire smoke near me?
On the AirNow Fire and Smoke Map 2.
Can I get air quality forecast notifications?
Yes, through EnviroFlash, where your state or local agency takes part 3.
Does an N95 mask help in smoke?
Ready.gov recommends an N95 mask to protect yourself from smoke inhalation 4.
A household plan can name your clean-air room and who in your home is most at risk.
Sources
- U.S. EPA / AirNow — AQI Basics — https://www.airnow.gov/aqi/aqi-basics/ (accessed 2026-10-27)
- U.S. EPA / AirNow — Wildfires — https://www.airnow.gov/wildfires/ (accessed 2026-10-27)
- U.S. Environmental Protection Agency (EPA) — EnviroFlash — https://www.enviroflash.info/ (accessed 2026-10-27)
- FEMA / Ready.gov — Wildfires — https://www.ready.gov/wildfires (accessed 2026-10-27)
- Atmospheric Composition Analysis Group, Washington University in St. Louis — Surface PM2.5, V6.GL.02.04 (CC BY 4.0) — https://sites.wustl.edu/acag/datasets/surface-pm2-5/ (accessed 2026-10-27)
- Copernicus Atmosphere Monitoring Service — CAMS global reanalysis (EAC4) — https://ads.atmosphere.copernicus.eu/ (accessed 2026-10-27)
- World Health Organization — WHO global air quality guidelines (2021) — https://www.who.int/publications/i/item/9789240034228 (accessed 2026-10-27)
Turn this into action
Your plan for United States, worked out for your household.
- Water, food and equipment counted for each person and pet
- The nuclear plants and zones around your home
- Phaenyx Safe: one tap to tell your people you are safe
Sources
- U.S. EPA / AirNow · AQI Basics checked 2026-10-27
- U.S. EPA / AirNow · Wildfires checked 2026-10-27
- U.S. Environmental Protection Agency (EPA) · EnviroFlash checked 2026-10-27
- FEMA / Ready.gov · Wildfires checked 2026-10-27
- Atmospheric Composition Analysis Group, Washington University in St. Louis · Surface PM2.5, V6.GL.02.04 (2021-2023 mean, median of U.S. cities) checked 2026-10-27
- Copernicus Atmosphere Monitoring Service · CAMS global reanalysis (EAC4), NO2 2021-2023 mean, median of U.S. cities checked 2026-10-27
- World Health Organization · WHO global air quality guidelines (2021) checked 2026-10-27