4. Black carbon as an emerging pollutant of concern
Black carbon emissions in the United States have declined substantially in the past 30 years, with large reductions in the onroad and nonroad diesel sectors. Emissions are projected to decline even further by 2030, largely due to controls on new mobile diesel emissions. In fact, most developed nations have already made significant progress in reducing emissions of black carbon and other direct sources of particulate matter. Further reductions are expected to occur over the next several decades as existing regulations are fully implemented.
Short and long-term exposures to PM2.5 are associated with a broad range of human health impacts, including respiratory and cardiovascular issues as well as premature death.
Black carbon is a short-lived climate pollutant with a lifetime of only days to weeks after release in the atmosphere. However, during this time, black carbon can have significant direct and indirect impacts on the climate, the cryosphere (snow and ice), agriculture and human health.