During a prescribed fire experiment, CO2 and particle number concentrations, light scattering and absorption coefficients were measured from a Cessna 172 airplane. Peak number concentrations were (3 ± 1) x 106 cm–3 and they decreased faster than what can be explained by coagulation alone. The single-scattering albedo of particles grew from the values of 0.4 ± 0.1 closest to the emissions to the values of 0.8 ± 0.1 at the distance of 400 m from the emissions. The mean Ângström exponent of absorption, 1.70 ± 0.24, is in line with the published spectral absorption values of wood-smoke aerosol. The estimated emission factors were 1600 ± 1020, 5.9 ± 6.3 and 1.4 ± 1.0 g kg–1 (dry biomass), for CO2, particulate organic matter and black carbon (BC), respectively, and (4.8 ± 2.9) x 1015 particles per kg (dry biomass) for the particle number. The BC emission factor may be overestimated by a factor of about 1.6 ± 0.2 due to condensation of organics on the filter of the absorption photometer. During the smoldering phase, there were clear indications of new particle formation.
Aki Virkkula, Toivo Pohja, Pasi Aalto, Petri Keronen, Siegfried Schobesberger, Craig Clements, Tuukka Petäjä, Juha Nikmo, and Markku Kulmala. "Airborne measurements of aerosols and carbon dioxide during a prescribed fire experiment at a boreal forest site" Faculty Publications (2014).