|| U.S. Environmental Protection Agency, Office of Air Quality Planning and Standards, Office of Atmospheric Programs, Office of Radiation and Indoor Air, Office of Research and Development, Office of Transportation and Air Quality,
Black carbon (BC) emissions have important impacts on public health, the environment, and the Earth's climate. BC is a significant component of particle pollution, which has been linked to adverse health and environmental impacts through decades of scientific research. Recent work indicates that BC also plays an important role in climate change, although there is more uncertainty about its effects on climate than for greenhouse gases (GHG), such as carbon dioxide and methane. BC has been linked to a range of climate impacts, including increased temperatures, accelerated ice and snow melt, and disruptions to precipitation patterns. Importantly, reducing current emissions of BC may help slow the near-term rate of climate change, particularly in sensitive regions such as the Arctic. However, BC reductions cannot substitute for reductions in long-lived GHGs, which are necessary for mitigating climate change in the long run. Despite the rapidly expanding body of scientific literature on BC, there is a need for a more comprehensive evaluation of both the magnitude of particular global and regional climate effects due to BC and the impact of emissions mixtures from different source categories. To advance efforts to understand the role of BC in climate change, on October 29, 2009, Congress requested the U.S. Environmental Protection Agency (EPA) conduct a BC study as part of H.R. 2996: Department of the Interior, Environment, and Related Agencies Appropriations Act, 2010.