Search

Abstract: Urban air quality is severely affected by traffic related particulate matter, including direct emissions from exhaust, brake pad, tire wear and road dust resuspended by vehicular motions. Deposited road dust can also be resuspended by wind force or other anthropogenic activities, and overall it may contribute up to 30% to urban PM10. A mobile resuspended road dust PM10 sampler was developed and constructed which simulates the effects of traffic or gusting winds on road surfaces and collects resuspended PM1−10 samples in a cyclone separator and PM1 samples on filters. The sampler was tested by collecting resuspended road dust at kerbside locations in Veszprém, Hungary. The collected PM1 and PM1−10 fractions were analysed by various analytical methods to show the potential of size-selective on-line sample collection combined with the chemical characterization of resuspended road dust. The main constituents of the resuspended road dust were crustal elements, and it was also possible to determine the mineral phase composition of PM1−10 dust which is generally not feasible from samples collected on filter substrate. The application of the sampling and analysis methods may facilitate the evaluation of resuspended road dust sources in cities as well as help constrain a better source apportionment of urban PM10. [Copyright &y& Elsevier]

Abstract: The particulate carbon content of precipitation was investigated in samples collected at five background sites located over a west-east European transect, from the Azores, in the mid-Atlantic Ocean, to the Hungarian plain, in central Europe. Sampling was performed on an event basis and the particulate carbon (elemental carbon, EC, and water insoluble organic carbon, WIOC) content was concentrated on quartz filters for the subsequent analysis by a thermal optical method in order to separate the EC and WIOC fractions. The average EC concentrations range from low values at the Azores (2.8±4.3μgCL−1) and at the high mountain site of Sonnblick (5.2±3.7μgCL−1) to high values at the more inland sites of Schauinsland (28±38μgCL−1) and K-Puszta (24±24μgCL−1). The average WIOC concentrations range from 98±56μgCL−1 at the coastal site of Aveiro and 113±78μgCL−1 at the Azores to 358±194μgCL−1 at the continental site of K-Puszta. These results are discussed in terms of factors affecting the spatial distribution of particulate carbon, such as emissions from surrounding areas and prevalent meteorological conditions. EC is found to be a minor contributor to total particulate carbon present in rain and snow samples (from 2.5% to 15%). This is particularly true at the remotes sites, where the EC contribution to total particulate carbon is <6.5%, consistent with a negligible impact of anthropogenic combustions locally. The EC and WIOC scavenging ratios were estimated and compared with those of sulfate, also evaluated at the same sampling sites. The results indicated that EC is removed from the atmosphere by wet deposition less efficiently than WIOC, and in turn this species is removed less efficiently than sulfate. [Copyright &y& Elsevier]