Black carbon emissions in China

Black carbon (BC) is an important aerosol species because of its global and regional influence on radiative forcing and its local effects on the envir onment and human health. We have estimated the emissions of BC in China, wh ere roughly one-fourth of global anthropogenic emissions is believed to ori ginate. China's high rates of usage of coal and biofuels are primarily resp onsible for high BC emissions. This paper pays particular attention to the application of appropriate emission factors for China and the attenuation o f these emissions where control devices are used. Nevertheless, because of the high degree of uncertainty associated with BC emission factors, we prov ide ranges of uncertainty for our emission estimates, which are approximate ly a factor of eight. In our central case, we calculate that BC emissions i n China in 1995 were 1342 Gg, about 83% being generated by the residential combustion of coal and biofuels, We estimate that BC emissions could fall t o 1224 Gg by 2020. This 9% decrease in BC emissions can be contrasted with the expected increase of 50% in energy use; the reduction will be obtained because of a transition to more advanced technology, including greater use of coal briquettes in place of raw coal in cities and towns. The increased use of diesel vehicles in the future will result in a greater share of the transport sector in total BC emissions. Spatially, BC emissions are predomi nantly distributed in an east-west swath across China's heartland, where th e rural use of coal and biofuels for cooking and heating is widespread. Thi s is in contrast Lo the emissions of most other anthropogenically derived a ir pollutants. which are closely tied to population and industrial centers. (C) 2001 Elsevier Science Ltd. All rights reserved.