AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
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Impact of Emissions from Incomplete Combustion Sources, Biomass Burning and Fossil Fuel, on Ambient Concentrations of Black Carbon (BC) in the Milan Metropolitan Area
AMIRHOSEIN MOUSAVI, Mohammad Sowlat, Christopher Lovett, Martin Rauber, Soenke Szidat, Roberto Boffi, Alessandro Borgini, Cinzia De Marco, Ario Ruprecht, Constantinos Sioutas, University of Southern California
Abstract Number: 25 Working Group: Source Apportionment
Abstract In the current work, spatial and temporal variation of black carbon (BC) concentrations originated from two important combustion sources, i.e. fossil fuel combustion and biomass burning, were evaluated at two sites, including Milan, a metropolitan area primarily impacted by urban emissions, and Bareggio, a sub-urban area located 14 km to the west of Milan, from summer 2017 to winter 2018. Using the Aethalometer model, sources of BC were apportioned based on the measurements performed using seven-wavelength (AEE33) and single-wavelength (AEE51) Aethalometers in Milan and Bareggio sampling sites, respectively. Our measurements demonstrated higher average combustion-generated BC concentrations at the Bareggio site (2763 ± 1050 ng.m-3) in comparison to the Milan site (1921 ± 876 ng.m-3). The Aethalometer model suggested a slightly higher annual average contribution of BC originated from fossil-fuel combustion (%BCff) in Milan (84.9 ± 5.4%) than in Bareggio (±4.1% ); however, contributions from biomass burning originated BC (%BCbb) were considerably higher in Bareggio (e.g., a wintertime average of 61.3±5.3%) than in Milan (e.g., a wintertime average of 30.5 ± 4.6%). Furthermore, %BCff trends showed a peak during the morning and afternoon rush hours in both Milan and Bareggio, when the highest traffic activities are excepted. On the other hand, a nighttime peak was observed for %BCbb when emissions from residential wood burning for heating purposes was prominent. In spite of the fact that traffic is a major source of combustion generated BC particles in the metropolitan Milan, our findings also revealed the key role of emissions from the residential wood burning on ambient BC concentrations in the area.