⌁AIRAHEAD

How to read the numbers

Methodology

How AirAhead calculates, compares and explains air-quality readings and forecasts.

The index

AirAhead primarily displays the US Air Quality Index (US AQI). It converts pollutant concentrations into a health-oriented scale. The overall value is driven by the highest pollutant sub-index rather than an average of every pollutant.

Local reports and forecasts

Location reports use gridded air-quality model data near the selected coordinates. Hourly and multi-day values are forecasts, so they can change as weather and emissions estimates are updated. The live map is a separate station view and should be treated as a point measurement.

City ranking

Each city is represented by one fixed central coordinate and its current modelled US AQI. This makes the list consistent and fast, but it does not describe every neighbourhood. Rankings are a snapshot, not a verdict on a city’s long-term air quality.

Country comparison

Country values are sample averages, not official national AQI figures. We average only the cities covered by AirAhead and show the number of sampled cities beside every result.

Update and uncertainty

Ranking responses are cached for 15 minutes. Model resolution, station siting, terrain, smoke events and local emissions can all create differences between services. Use local official alerts for urgent decisions.