Characterization of unique aerosol pollution episodes in urban areas using TXRF and TXRF-XANES

Identifying sources of unique, short-time aerosol pollution episodes in urban areas is a difficult task since they could last only for a couple of hours. With the combination of size-fractioned sampling with May-type cascade impactor and total-reflection X-ray fluorescence (TXRF) in addition to X-ray absorption near-edge structure spectroscopy various sources could be identified in samples collected in Budapest (Hungary) and Cassino (Italy). Using short-time (1-4 h), size-fractionated (70 nm up to 10 mu m into 7 stages) sampling method, TXRF is capable of detecting transition metals in the order of 0.1 ng/m(3). The present study discusses pollution episodes with Cu and Br concentrations in the range of 1-40 ng/m(3). The contribution of both exhaust and non-exhaust type traffic-related emission sources were found to be dominant in the Cu species. Wear products of brake system were identified in coarse particles in addition to resuspension of roadside dust. The ratio of organic/inorganic Br could be determined for a pollution episode with elevated Br concentration.

Automated summary

Identifying sources of short-time aerosol pollution episodes in urban areas is challenging due to their brief duration. The method of combining size-fractioned sampling with TXRF proved effective in detecting transition metals at low concentrations. Both exhaust and non-exhaust traffic-related emission sources were found to contribute significantly to copper species during pollution episodes.