The large scale baseline comes from NASA’s GEOS-CF forecast worldwide, and from Copernicus Atmosphere Monitoring Service (CAMS) across Europe. Neighbourhood structure comes from emissions inventories, land use, terrain, roads and weather. Ground measurements train and test that picture. Outside Europe we use historical observations accessed through OpenAQ. In Europe and the UK we use regulatory monitoring networks. Independent sensors are held out of training so we can check the model against data it has never seen. Indoor exposure uses an infiltration model based on established indoor air quality literature. In-vehicle exposure is estimated from your route, travel mode and vehicle cabin assumptions.
