Trend in global black carbon emissions from 1960 to 2007.

Black carbon (BC) plays an important role in both climate change and health impact. Still, BC emissions as well as the historical trends are associated with high uncertainties in existing inventories. In the present study, global BC emissions from 1960 to 2007 were estimated for 64 sources, by using recompiled fuel consumption and emission factor data sets. Annual BC emissions had increased from 5.3 (3.4-8.5 as an interquartile range) to 9.1 (5.6-14.4) teragrams during this period. Our estimations are 11-16% higher than those in previous inventories. Over the period, we found that the BC emission intensity, defined as the amount of BC emitted per unit of energy production, had decreased for all the regions, especially China and India. Improvements in combustion technology and changes in fuel composition had led to an increase in energy use efficiency, and subsequently a decline of BC emission intensities in power plants, the residential sector, and transportation. On the other hand, the BC emission intensities had increased in the industrial and agricultural sectors, mainly due to an expansion of low-efficiency industry (coke and brick production) in developing countries and to an increasing usage of diesel in agriculture in developed countries.