Аннотация:Reliable assessment of the impact of Siberian boreal forest wildfires on the environment and climate necessitates an
improved understanding of microphysical and chemical properties of emitted aerosols. Smoldering, flaming and mixed
fires of typical Siberian biomass (pine and debris) were simulated during a small-scale study in a Large Aerosol Chamber
(LAC). Individual particle analysis of PM10 and PM2.5 smoke morphology and elemental composition revealed a strong
dependence on combustion temperature, i.e., a dominant abundance of soot agglomerates versus roughly spherical organic
particles in the flaming and smoldering phase, respectively. Cluster analysis of smoke microstructure was used to
apportion the emitted particles into major characteristic groups: Soot and Organic, which accounted for around 90% and
60% of total particle numbers emitted from the flaming and smoldering fires, respectively. Carbon fractions and inorganic
ion analysis supported the identification of particle types representative of combustion phase and biomass type. Elemental
carbon (EC) particles from flaming fires comprised approximately 25% of Group Soot, in good agreement with a high EC
fraction in total carbon of around 65% and low organic carbon (OC)/EC ratio near 0.5. Smoldering fires of pine and debris
produced exclusively organic particles with high OC/EC ratios of 194 and 34, respectively. Small quantities of elemental
constituents in biomass were vaporized during combustion and produced internally/externally mixed fly ash in Group Ca-,
Si-, and Fe-rich of significantly less abundance. Ca, Cl, S, and Mg were more frequently distributed elements in pine than
debris smoke. Sulfates and nitrates produced from gas-to-particle reactions formed Group S- and N-rich. During time
evolution of smoke volatile inorganic compounds were condensed as potassium chlorides and sulfates into a newly formed
Group K,Cl-rich. Quantification of Siberian biomass smoke microstructure by chemical micromarkers enables aerosols to
be classified with respect to a source type assigned to Siberian wildfires.