Number of substances detected by active air sampling in Hallahus, Sweden, in 2017 . F testing cartridge, P pesticides, PUF polyurethane foam (first section of the testing cartridge). The red line represents all substances detected in Hallahus, Sweden. The number was calculated by adding the total number of substances detected in the glass fibre filter (blue line) and the total number of substances detected in the PUF (yellow line). The number of identical substances detected in both glass fibre filter and PUF (green line) was then substracted from the total to remove duplicates.