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Data: Open-Meteo air-quality model (CAMS sources), updated hourly.
From µg/m³ to a single index
PM2.5, PM10, ozone, NO₂, SO₂ and CO are measured together and ranked by dominance, so you always know what drives today's index.
Peak daily AQI capsule bars reveal whether the air is clearing or degrading - plan outdoor work and exercise around it.
Every reading comes with practical guidance tuned to its band, from open-window days to mask recommendations.
Why PM2.5 dominates air-quality talk
Air quality is judged by six regulated pollutants: particulate matter (PM10 and especially PM2.5), ground-level ozone, nitrogen dioxide, sulphur dioxide and carbon monoxide. PM2.5 is the headline actor - combustion particles small enough to cross from the lungs into the bloodstream, linked to cardiovascular and respiratory disease. Ozone spikes on hot sunny afternoons, NO₂ tracks traffic, and SO₂ follows heavy industry and coal burning.
Making sense of the station
- 🌫️ The big dial shows the US-AQI composite - one number summarizing the worst contributor, with a needle that sweeps to its position on the scale
- 🔬 Pollutant chips show each concentration in µg/m³ sorted by dominance, so you always know what drives today's index
- 📊 The 3-day capsule bars reveal whether an episode is improving or getting worse
Use the advice panel rather than raw numbers alone: sensitivity varies hugely between healthy adults, children, older people and anyone with asthma or heart conditions. On high-AQI days the cheapest protections - staying indoors during peaks, filtration, and well-fitted masks - measurably reduce exposure.
Reading the health station
- The dial shows the US-AQI composite; its color matches EPA bands from green (good) to maroon (hazardous) and the needle sweeps to position.
- Pollutant chips are sorted by concentration, highlighting the dominant contributor first.
- Capsule bars use the same scale, so today's bar versus tomorrow's tells the trend instantly.
From µg/m³ to a single index
- Type any city - suggestions appear as you type, or tap one of the quick-pick pills.
- We fetch the latest modeled pollutant concentrations and the US-AQI composite for those coordinates.
- Watch the gauge sweep to your index, compare pollutant chips, then follow the band-tuned advice.
FAQ
The US Air Quality Index condenses several pollutants into one 0-500 scale. Below 50 is good, 51-100 is moderate, 101-150 is unhealthy for sensitive groups, and anything above 200 affects everyone. This station shows the official US-AQI computed from ground-model concentrations.
Which pollutant matters most?PM2.5 - particles under 2.5 micrometers - is generally the most health-relevant because it penetrates deep into the lungs and bloodstream. That is why it leads the AQI weighting in most regions, and why it usually tops the dominance-sorted chips.
How accurate and current are the values?Values come from the Open-Meteo air-quality model built on the Copernicus Atmosphere Monitoring Service, updated hourly. Model estimates are very close to station data for most cities, though individual street-level hotspots can differ.
Is it free?Completely free, no account needed. City searches and readings are cached briefly on our edge, so repeated checks stay fast.
Why PM2.5 dominates air-quality talk
Air quality is judged by six regulated pollutants: particulate matter (PM10 and especially PM2.5), ground-level ozone, nitrogen dioxide, sulphur dioxide and carbon monoxide. PM2.5 is the headline actor - combustion particles small enough to cross from the lungs into the bloodstream, linked to cardiovascular and respiratory disease. Ozone spikes on hot sunny afternoons, NO₂ tracks traffic, and SO₂ follows heavy industry and coal burning.
Making sense of the station
- 🌫️ The big dial shows the US-AQI composite - one number summarizing the worst contributor, with a needle that sweeps to its position on the scale
- 🔬 Pollutant chips show each concentration in µg/m³ sorted by dominance, so you always know what drives today's index
- 📊 The 3-day capsule bars reveal whether an episode is improving or getting worse
Use the advice panel rather than raw numbers alone: sensitivity varies hugely between healthy adults, children, older people and anyone with asthma or heart conditions. On high-AQI days the cheapest protections - staying indoors during peaks, filtration, and well-fitted masks - measurably reduce exposure.
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