| Title: | Neighbourhood-scale dispersion of traffic-induced ultrafine particles in central London: WRF large eddy simulations |
| Author(s): | Zhong J; Nikolova I; Cai X; MacKenzie AR; Alam MS; Xu R; Singh A; Harrison RM; |
| Address: | "School of Geography, Earth & Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK. School of Geography, Earth & Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK. Electronic address: x.cai@bham.ac.uk. School of Geography, Earth & Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK; Birmingham Institute of Forest Research, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK. School of Geography, Earth & Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK; Department of Environmental Sciences, Center of Excellence in Environmental Studies, King Abdulaziz University, PO Box 80203, Jeddah, 21589, Saudi Arabia" |
| DOI: | 10.1016/j.envpol.2020.115223 |
| ISSN/ISBN: | 1873-6424 (Electronic) 0269-7491 (Linking) |
| Abstract: | "Traffic-generated ultrafine particles (UFPs) in the urban atmosphere have a high proportion of their composition comprised of semi-volatile compounds (SVOCs). The evaporation/condensation processes of these SVOCs can alter UFP number size distributions and play an important role in determining the fate of UFPs in urban areas. The neighbourhood-scale dispersion (over distances < 1 km) and evolution of traffic-generated UFPs for a real-world street network in central London was simulated by using the WRF-LES model (the large eddy simulation mode of the Weather Research and Forecasting modelling system) coupled with multicomponent microphysics. The neighbourhood scale dispersion of UFPs was significantly influenced by the spatial pattern of the real-world street emissions. Model output indicated the shrinkage of the peak diameter from the emitted profile to the downwind profile, due to an evaporation process during neighbourhood-scale dispersion. The dilution process and the aerosol microphysics interact with each other during the neighbourhood dispersion of UFPs, yielding model output that compares well with measurements made at a location downwind of an intense roadside source. The model captured the total SVOC concentrations well, with overestimations for gas concentrations and underestimations for particle concentrations, particularly of the lighter SVOCs. The contribution of the intense source, Marylebone Road (MR) in London, to concentrations at the downwind location (as estimated by a model scenario with emissions from MR only) is comparable with that of the rest of the street network (a scenario without emissions from MR), implying that both are important. An appreciable level of non-linearity is demonstrated for nucleation mode UFPs and medium range carbon SVOCs at the downwind receptor site" |
| Keywords: | Air Pollutants/*analysis Environmental Monitoring London Particle Size Particulate Matter/*analysis Vehicle Emissions/analysis Multicomponent microphysics Nucleation mode Semi-volatile organic compounds Urban air quality; |
| Notes: | "MedlineZhong, Jian Nikolova, Irina Cai, Xiaoming MacKenzie, A Rob Alam, Mohammed S Xu, Ruixin Singh, Ajit Harrison, Roy M eng England 2020/07/31 Environ Pollut. 2020 Nov; 266(Pt 3):115223. doi: 10.1016/j.envpol.2020.115223. Epub 2020 Jul 20" |
