Mass absorption efficiency of elemental carbon for source samples from residential biomass and coal combustions

Optical properties of particulate matter are of growing concern due to their complex effects on atmospheric visibility and local/regional climate change. In this study, mass absorption efficiency (MAE) of elemental carbon (EC) was measured for source emission samples obtained from the residential combustions of solid fuels using a thermal-optical carbon analyzer. For source samples from residential wood, crop straw, biomass pellet and coal combustions, MAE of EC measured at 650 nm, were 3.1 (2.4-3.7 as 95% Confidence Interval), 6.6 (5.5-7.6), 9.5 (6.7-12), and 7.9 (4.8-11) m2 g−1, respectively. MAE of EC for source sample from the wood combustion was significantly lower than those for the other fuels, and MAE of EC for coal briquette appeared to be different from that of raw chunk. MAE values of the investigated source emission samples were found to correlate with OC/EC ratio, and a significantly positive correlation was found between MAE and particle-bound polycyclic aromatic hydrocarbons (pPAHs), though pPAHs contributed a relatively small fraction of OC.