Air Quality Near Me
See the air quality index (AQI) for your location right now, the main pollutant, and levels of PM2.5, PM10, ozone, nitrogen dioxide, carbon monoxide and sulfur dioxide. An hourly chart shows the past 24 hours and the forecast for the next 48, so you can pick the best time to be outside.
Last updated:
Loading air quality…
–
Hourly: past 24 hours and next 48 hours
How to use the Air Quality Near Me
- Choose a place: the page opens on your last place (or New York). Search a city or postcode, type lat, lon, or press Use my location.
- Read the AQI: the coloured card shows the index now, its category and the main pollutant, with what the level means for outdoor activity.
- Pick a scale: switch between the US AQI (0 to 500) and the European AQI (0 to 100+). Your choice is remembered.
- Check each pollutant: the cards list concentrations in µg/m³ and how they compare with the WHO guideline values.
- Plan ahead: use the hourly chart and the best and worst hour cards to time a run, a walk or opening windows.
US AQI categories and what they mean
| AQI | Category | Color | Who should take care | PM2.5 24-h (µg/m³)* |
|---|---|---|---|---|
| 0 to 50 | Good | Green | No one; enjoy outdoor activity | 0 to 9.0 |
| 51 to 100 | Moderate | Yellow | Unusually sensitive people | 9.1 to 35.4 |
| 101 to 150 | Unhealthy for sensitive groups | Orange | People with heart or lung disease, older adults, children, teens | 35.5 to 55.4 |
| 151 to 200 | Unhealthy | Red | Everyone may notice effects | 55.5 to 125.4 |
| 201 to 300 | Very unhealthy | Purple | Health alert for everyone | 125.5 to 225.4 |
| 301+ | Hazardous | Maroon | Emergency conditions | 225.5 and above |
*PM2.5 break points from the US EPA's 2024 update of the AQI. Other pollutants (ozone, PM10, NO₂, CO, SO₂) each have their own break points; the reported AQI is the highest of the individual sub-indices.
WHO 2021 air quality guideline levels
| Pollutant | Averaging time | Guideline level | Main sources |
|---|---|---|---|
| PM2.5 | 24 hours / 1 year | 15 / 5 µg/m³ | Traffic, heating, industry, wildfire smoke |
| PM10 | 24 hours / 1 year | 45 / 15 µg/m³ | Dust, construction, road wear, pollen, sea salt |
| Ozone (O₃) | 8 hours (daily maximum) | 100 µg/m³ | Formed in sunlight from NOx and VOCs |
| Nitrogen dioxide (NO₂) | 24 hours / 1 year | 25 / 10 µg/m³ | Vehicle exhaust, power plants, gas stoves |
| Sulfur dioxide (SO₂) | 24 hours | 40 µg/m³ | Burning coal and oil, smelters, volcanoes |
| Carbon monoxide (CO) | 24 hours | 4 mg/m³ (4,000 µg/m³) | Incomplete combustion, traffic |
Tips for days with poor air
- Time your activity: use the hourly chart. Particle levels are often higher in the morning and evening rush hours and on calm nights; ozone usually peaks in the afternoon.
- Choose the route: walking or cycling a few blocks away from heavy traffic can noticeably lower your exposure to NO₂ and ultrafine particles.
- Indoors: keep windows closed during smoke events and run a HEPA air purifier or a central system with a high-efficiency (MERV 13 or better) filter.
- Follow local alerts: official agencies use nearby monitors and may issue health advisories that a regional model cannot capture.
Frequently asked questions
What is a good AQI?
On the US EPA scale, 0 to 50 is Good and 51 to 100 is Moderate. 101 to 150 is Unhealthy for Sensitive Groups, 151 to 200 Unhealthy, 201 to 300 Very Unhealthy and 301 or more Hazardous. On the European index, 0 to 20 is Good, 20 to 40 Fair, 40 to 60 Moderate, 60 to 80 Poor, 80 to 100 Very poor and above 100 Extremely poor.
What is PM2.5 and why does it matter?
PM2.5 is particulate matter smaller than 2.5 micrometers, about 30 times thinner than a human hair. It comes from vehicles, industry, heating, dust and wildfire smoke, and is small enough to reach deep into the lungs. The WHO 2021 guideline is 15 µg/m³ as a 24-hour average and 5 µg/m³ as an annual average.
Where does this air quality data come from?
The values come from the Open-Meteo Air Quality API, which uses the Copernicus Atmosphere Monitoring Service (CAMS) forecast models. These are model estimates for a grid cell (about 11 km in Europe and 25 to 45 km elsewhere), not readings from a single ground monitor, so local hot spots such as a busy road or a nearby fire can differ. For official alerts, check your local or national air quality agency.
Why do the US and European AQI give different numbers?
They use different scales and break points. The US AQI runs from 0 to 500 and uses 24-hour averages for particles and 8-hour averages for ozone; the European AQI runs from 0 to 100+ and is based on hourly concentrations. The same air can be Moderate on one scale and Fair or Poor on the other, so compare readings on the same scale.
How is the US AQI calculated?
For each pollutant the EPA converts the concentration to a sub-index with linear interpolation between break points: AQI = (I_hi − I_lo) / (C_hi − C_lo) × (C − C_lo) + I_lo. The overall AQI is the highest sub-index, and that pollutant is reported as the main pollutant. For example, a 24-hour PM2.5 average of 35.4 µg/m³ corresponds to an AQI of 100 under the 2024 EPA break points.
Is ozone worse in the afternoon?
Usually yes. Ground-level ozone forms when sunlight drives reactions between nitrogen oxides and volatile organic compounds, so it tends to build through the day and peak in the mid to late afternoon on hot, sunny days, then fall at night. Morning is often the better time for outdoor exercise on high-ozone days.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.