Small-Scale Study of Siberian Biomass Burning: II. Smoke Hygroscopicity

Abstract

A lack of understanding about the impact of Siberian wildfire emissions on the environment necessitates the characterization of biomass burning aerosol hygroscopicity. Flaming fires of typical Siberian biomass (pine and debris) were simulated during small-scale combustion experiments in a Large Aerosol Chamber (LAC). Analyses of individual particles with respect to morphology and elemental composition allows the separation of freshly-produced smoke into five fractions with the elemental carbon, chain soot agglomerates, irregular internally mixed soot, and distinct irregular minerals of fly ash containing S, Ca, Al, and Si. Aging in a dark chamber leads to an appearance of the fraction with inorganic inclusions such as KCl and CaCl 2 . Categorization of fresh-emitted and aged particles on hydrophobic, hydrophilic, and hygroscopic ones is performed. The criteria for categorization are extended from fossil fuel hightemperature combustion, based on a concept of water uptake by soot particles and utilization of a number of reference soots with known oxygen content and mixtures with sulfates and other inorganic salts. We show how the hydration properties of emitted smoke particles and inorganic inclusions can increase the initial level of smoke hygroscopicity.

Aerosol Emissions from Long-lasting Smoldering of Boreal Peatlands: Chemical Composition, Markers, and Microstructure

“…4(b) shows the absorption bands of water-soluble compounds of peat bog smoke. According to the most hygroscopic species identified in the particle composition (Kireeva et al, 2009;Popovicheva et al, 2016c) ; 923 cm -1 ), and carbonates (CO 3 -; 1423 cm -1 ) as well as of C=O (1754, 1645 cm -1 ) in anhydrates and amino acids/acid carbonyls, -NO 2 (1527 cm -1 ) in nitro compounds, and C-N (1204 cm -1 ) in amines. These functionalities are predominant in thin smoke inside as well as in smoke above grass similar to total aerosol spectra.…”