Black and Brown Carbon in Atmospheric Aerosols

Black Carbon (BC), emitted mainly by high-temperature combustion processes (diesel engines, etc.) and Brown Carbon (BrC), emitted mainly by biomass combustion are the two most important light absorbing substances in the atmospheric aerosol. The absorptive properties of these substances can have large impacts on radiative transfer and climate. Despite more than 30 years of research, no standard measurement method for BC is available. The only direct technique to estimate the concentration of BrC was developed here, and was included in collaborative, intensive measurement method comparisons, which showed that BrC can lead to large differences in common BC measurement methods. We now investigate the physical basis of the various interferences in the measurement techniques.