Emission characteristics of carbonaceous particles from various residential coal-stoves in China.

China is thought to be the most important contributor to the global burden of carbonaceous aerosols, and residential coal combustion is the greatest emission source of black carbon (BC). In the present study, two high-efficiency household coal-stoves are tested together with honeycomb-coal-briquettes and raw-coal-chunks of nine different coals. Coal-burning emissions are collected onto quartz fiber filters (QFFs) and analyzed by a thermal-optical transmittance (TOT) method. Emission factors (EFs) of particulate matter (PM), organic carbon (OC), and elemental carbon (EC) are systematically measured, and the average EFs are calculated by taking into account our previous data. For bituminous coal-briquette and -chunk, EFs of PM, OC, and EC are 7.33, 4.16, and 0.08 g/kg and 14.8, 5.93, and 3.81 g/kg, respectively; and for anthracite-briquette and -chunk, they are 1.21, 0.06, and 0.004 g/kg and 1.08, 0.10, and 0.007 g/kg, respectively. Annual estimates for PM, OC, and EC emissions in China are calculated for the years of 2000 and 2005 according to the EFs and coal consumptions, and the results are consistent with our previous estimates. Bituminous coal-chunk contributes 68% and 99% of the total OC and EC emissions from household coal burning, respectively. Additionally, a new model of Aethalometer (AE90) is introduced into the sampling system to monitor the real-time BC concentrations. On one hand, AE90 provides a set of EFs for optical BC in parallel to thermal-optical EC, and these two data are generally comparable, although BC/EC ratios vary in different coal/stove combinations. On the other hand, AE90 offers a chance to observe the variation of BC concentrations during whole burning cycles, which demonstrates that almost all BC emits into the flue during the initial period of 15 min after coal addition into household stoves.