How bythenumbers measures modelled nitrogen dioxide and fine particulate levels for a cell about 0.6 miles across.
This category uses DEFRA's modelled annual mean nitrogen dioxide and fine particulate figures on a grid of cells about 0.6 miles across. It describes the cell a postcode sits in, not a sensor on a particular kerb, and not a live pollution episode. A higher figure means lower modelled pollution, not dirtier air.
Background air quality is one of the environmental facts that is hard to see on a viewing. It matters more if anyone in the household has asthma, or if you will spend time walking along busy roads. The national model is consistent enough to compare areas, with the caveat that a grid cell is not a street.
You cannot smell the annual mean on a Saturday viewing. Putting the modelled figure next to flood zones and green space gives you the published environmental picture before you offer. Then walk the street at rush hour. The model is the comparable baseline, not a substitute for being there.
Licences and refresh cadence are on the sources page.
Search any UK postcode to see this category on a live report, beside the rest of the Area Measure.