Black carbon is a type of fine particulate matter that is produced through the incomplete combustion of fossil fuels, biomass, and biofuels. It is commonly referred to as soot and can be emitted from a variety of sources such as diesel engines, industrial processes, cooking stoves, and wildfires.

Black carbon is primarily used as a component in the manufacture of black ink, black pigments, and toners. It is also used in some types of batteries, as a reinforcing filler in rubber and plastic products, and as a heat transfer agent in some industrial processes.

The production and use of black carbon can have significant environmental impacts. Black carbon is a potent contributor to climate change because it absorbs sunlight and contributes to the warming of the Earth's atmosphere. Additionally, when black carbon particles are deposited on snow and ice, they can reduce their reflectivity, which in turn leads to further warming.

Black carbon can also have significant impacts on human health, particularly in areas where exposure to high levels of particulate matter is common. The inhalation of black carbon particles can lead to respiratory and cardiovascular problems and can exacerbate existing health conditions such as asthma and bronchitis.

Finally, black carbon can have significant impacts on the environment. When it is released into the atmosphere, it can contribute to acid rain and can also be deposited onto soil and water, where it can have negative impacts on ecosystems and biodiversity. Additionally, the deposition of black carbon onto snow and ice can lead to the melting of glaciers and snowpack, which can have significant impacts on water resources and the environment.