Check the Air Where You Are
Every search reads live air-quality model data for the next 24 hours. Nothing is stored and no signup is needed.
About this air quality checker
The Air Quality Index (AQI) checker turns live air-pollution model data into one plain answer: how polluted is the air right now, what should you do about it today, and when is the next clean window. Type a city name or press the location button, and the tool reads the current US AQI plus the next 24 hours of hourly AQI from Open-Meteo, a free forecast API that aggregates European (CAMS) and national air-quality models. The US AQI is the 0-500 scale used by the EPA and by both IQAir and AQICN, so the number you see here is directly comparable with what other sites and news reports publish. Nothing is stored: the request goes from your browser straight to Open-Meteo, and there is no signup, no account, and no cookie wall.
What the verdict means
The big number is the current US AQI with its official category. The verdict line under it translates that category into a decision: whether most people can exercise outside, whether asthma or heart patients, children and older adults should reduce long outdoor effort, and whether windows should stay shut. The dominant-pollutant row names which pollutant is driving today's reading, because the fix depends on the cause: peak ozone happens around midday glare, PM2.5 and PM10 spike overnight during smog and wildfire smoke events, and a high NO₂ reading usually means traffic nearby rather than smoke.
The next 24 hours
Every search also renders the next 24 hours of AQI as a small strip chart and marks the cleanest and the worst hour, so you can plan the run, the dog walk, or open-the-windows time instead of guessing. Polluted episodes move fast: a smoke plume or a temperature inversion can double the AQI between dinner and midnight, while morning traffic peaks fade by mid-morning. A verdict is a plan only if it tells you when the numbers change, so re-checking around 7 PM and 6 AM covers the two biggest hour-to-hour swings in most cities.
Model data, not one street sensor
The AQI here comes from a city-scale model grid, the same approach national weather services use for forecasts. Monitor networks (AirNow in the US, CPCB in India, national agencies elsewhere) release exact street readings minutes to hours later, and a hypersensitive monitor can report a spike one station cannot. That is why two sites can disagree by a few points at the same moment. Model AQI is steadier and comparable between cities, and if you need the official single-monitor reading for your immediate street during a wildfire, your local environmental agency is the source of record.
Air quality FAQ
What is the air quality index (AQI)?
The AQI is a 0-500 scale that folds several pollutants into one number you can act on. The US EPA version is computed from PM2.5, PM10, ozone (O₃), nitrogen dioxide (NO₂), sulfur dioxide (SO₂) and carbon monoxide (CO): whichever pollutant is worst that hour sets the AQI. 0-50 is Good (green), 51-100 Moderate (yellow), 101-150 Unhealthy for Sensitive Groups (orange), 151-200 Unhealthy (red), 201-300 Very Unhealthy (purple), and 301+ Hazardous (maroon). Higher is always worse.
Why does my weather app show a different number than this page?
Three honest reasons. First, different scales: some apps show the European AQI (EAQI) or a national scale such as India's CPCB index, which judge thresholds differently from the US AQI used here. Second, different sources: your app may quote one street monitor while this page shows the model average across your city. Third, update times: models publish hourly while a monitor updates every few minutes, so during a fast-moving smoke plume the two disagree until both catch up. Compare the number's label, not just its value.
Which pollutant is PM2.5 and why does it matter most?
PM2.5 is fine particulate matter under 2.5 microns, about 30 times thinner than a human hair. It matters most because it reaches deep into the lungs and even the bloodstream, and it is the pollutant most strongly tied to hospital admissions, heart disease and early deaths in the research behind the WHO 2021 guideline. Wildfire smoke, vehicle exhaust, coal plants and dust storms all raise PM2.5. The WHO 2021 guideline is 15 µg/m³ per 24 hours, and the US AQI unhealthy threshold for PM2.5 is correspondingly strict.
What AQI level is safe for running, kids and asthma?
At 0-50 everyone can exercise freely. From 51-100 most people can run and play outside, but unusually sensitive individuals may want to shorten intense sessions. From 101-150, people with asthma, heart or lung conditions, children and adults over 65 should cut long or intense outdoor effort, and everyone else should watch for symptoms. From 151-200, everyone reduces strenuous activity and finds indoor time; 201+ means move it indoors completely where you can. If your city sits above 150 for consecutive days, run indoors and use a filter.
How do I reduce exposure when the AQI is bad?
Cut the time and the intensity, not just the distance. Exercise outdoors early in the window the chart marks cleanest, shift hard sessions indoors, keep windows closed during the worst hours in wildfire or heavy smog episodes and after travel peaks on streets with heavy traffic. For indoor air, filter PM2.5 with a HEPA air purifier or a box fan with a furnace filter taped on, and skip candles, incense and frying that raise indoor PM2.5 further. Masks rated N95 or better filter particulates when outdoor exposure cannot be avoided.
Is this tool private, and does it cost anything?
It is free with no signup, no account, and nothing is stored. Your typed city or coordinates go directly from your browser to Open-Meteo, the free API that provides the air-quality forecast; this site never sees your location or your searches. The page sets no cookies and tracks nothing, so it is safe on a shared computer.
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