Guide
Modelled vs measured air quality: why the numbers differ
Last reviewed 4 Nov 2026 · DanixSoft
A station measures the air at one spot; a model estimates it for a whole grid square from emissions, weather and satellite data. Saans’s main number is the CAMS model (via Open-Meteo, about 45 km squares), which covers every city and gives a forecast. Where a monitoring station is within 15 km, Saans also shows its latest reading. When the two differ, the station is closer to what is in the air at that spot right now; the model is better for the trend and the days ahead.
What this means for areas
Areas inside one city, such as Gulberg and DHA in Lahore, usually fall in the same model square, so they show the same modelled AQI. Real air differs by street: busy roads, industry and open burning push it up. Area pages say this plainly and show the nearest station when there is one.
Known limits of the model
- It can miss sudden local events (a nearby fire, a dust storm starting).
- Emissions data for South Asia are uncertain, so absolute numbers can be too high or too low; the day-to-day trend is more reliable.
- The update time shown is the model hour, refreshed hourly.