Validation of a gravimetric PM2.5 impactor using particle sizing techniques

Particulate matter sampling was conducted at Ballidon Quarry, Ballidon, Derbyshire. The quarry is owned and managed by Tarmac Trading Ltd. (Tarmac). The monitoring station deployed comprised two DS500X gravimetric samplers fitted with PM2.5 impactors, that were placed side by side in the primary crusher shed during February 2016. Monitoring was conducted over three, seven day periods. Particulate matter from six filters and oversize particulate matter collected from the impactor plates were analysed by BGS on behalf of DustScan using Scanning Transmission Electron Microscopy and Laser Diffraction granulometry. The results of the work show that the DS500X fitted with a PM2.5 size selective impactor is capable of separating particles with a projected area diameter of ≤ 2.5 μm from ambient air, retaining themon filter media for subsequent quantification. The overall median particle size recorded on the filters was 0.46 μm, the mean was 0.74 μm and the 95th percentile was 2.15 μm (n = 6343). A number of observations were made during this study and included in the full report which should be considered when interpreting the results.