Physicochemical characterization of smoke aerosol during large-scale wildfires: Extreme event of August 2010 in Moscow

摘要: Abstract Enhancement of biomass burning-related research is essential for the assessment large-scale wildfires impact on pollution at regional and global scale. Starting since 6 August 2010 Moscow was covered with thick smoke unusually high PM10 BC concentrations, considerably affected by huge forest peat fires around megacity. This work presents first comprehensive physico-chemical characterization aerosols during extreme event in 2010. Sampling performed center suburb as well one year later, 2011 a period when no burning observed. Small-scale experimental were conducted region. Carbon content, functionalities organic/inorganic compounds, tracers (anhydrosaccharides), ionic composition, structure analyzed thermal-optical analysis, FTIR spectroscopy, liquid ion chromatography, electron microscopy. Carbonaceous aerosol dominated organic species elemental carbon (EC) minor component. High average OC/EC near 27.4 found, comparable to smoldering fire, exceeded 3 times value observed 2011. Organic hydroxyl, aliphatic, aromatic, acid non-acid carbonyl, nitro compound groups, almost all them indicate city source smoke. The ratio levoglucosan (LG) mannosan 5 confirms origin from coniferous Low LG/OC 0.8% indicates degradation major molecular tracer urban environment. Total concentration inorganic ions sulfates SO 4 2 − ammonium NH + found about higher than Together strong sulfate absorbance aerosols, these observations prove formation secondary associated wildfire gaseous emissions their transformation aged Accumulation carbonyl compounds resulted photochemical aging (SOA) atmosphere. mixture carbonaceous particles dust revealed multicomponent pointing difference non-smoke ambient aerosols. abundance group containing soot tar balls approached least half total event, relating elevated OC, EC SOA. Fly ash groups contained calcium carbonates soil entrainment hot air convection. open fire experiments support identification specific chemical features demonstrate chemistry quality highly polluted