| Interactions of visible radiation with atmospheric aerosols are important to the heat balance of the Earth. Accurate emission inventories of particles from combustion are required to predict anthropogenically-induced changes in the radiative balance. I present measurements of the optical properties of particles from several types of combustion and compare them with assumptions used in previous emission inventories.; Emissions from an indirect-injection diesel engine were similar to expected values. However, a second engine with a direct-injection scheme emitted about 100 times the expected amount of both mass and light absorption because of a poor injection pattern. Total emissions from vehicles depend critically on the number of such “catastrophic” units in operation.; Absorption emitted from a low-technology industrial lignite-burning furnace was about 20 times lower than previous estimates; the emitted particles contained partially aromatized carbon. Burning bituminous coal in a Chinese-style domestic combustor yielded significant light absorption, similar to published emission factors. Combustion of both coal briquettes obtained from China and lignite resulted in very low light absorption because tar release from these fuels was low.; Combining the measurement and modeling results with an extensive literature survey, I estimated central, low and high values of emission factors for different fuels and combustion sectors. I then calculated a global emission inventory of light-absorbing carbon from fossil-fuel combustion. The total emission of light-absorbing carbon for 1994 is 3.7 Tg, about half the magnitude of previously published emission inventories. The upper and lower uncertainty boundaries are 0.8 and 44 Tg year–1. The largest sources of uncertainty are emission characteristics for residential coal and the existing fraction of “catastrophic” units in operation. Emission inventories for organic carbon (central value of 5.1 Tg year–1, with a range of 0.5-42 Tg year–1) and for primary particles (3 × 1028 year–1) are also presented.; Radiative forcing by light-absorbing particles on a global-average basis is small, but regional effects are significant. In regions with high area-specific emissions, the central estimate of top-of-atmosphere forcing is about +0.7 W m–2, and the upper bound is around +4.0 W m –2. |
