Ice nuclei from biomass burning emissions

This study summarizes the results of sampling of ice nuclei (IN) and other aerosol properties under the influence of biomass burning emissions, in the laboratory, under controlled burning scenarios in the atmosphere, and for smokes from large wildfires. In both the laboratory and the atmosphere, we find that biomass combustion directly or indirectly leads to highly varied contributions of IN, depending on both biomass type and combustion conditions. In laboratory and controlled burns, most biomass types investigated thus far are only weak sources of ice nuclei that may have only local or regional influence during higher smoke loading periods. A few types stand out as highly active IN. Large wildfires within similar biomass regimes as prescribed burns appear to represent much more potent sources of IN to the atmosphere. We further investigate types of IN from different burns using collections of activated IN for electron microscopy analyses, with a particular focus on the likely contributions of black carbon versus other IN such as soil particles.