Black carbon is produced by incomplete combustion of fuels such as diesel, coal and wood. Combustion might take place in the open air (for example bonfires) or more typically in an engine or a boiler.
In the UK most black carbon comes from diesel engines. These include diesel vehicles on the road, but also construction equipment, agricultural machinery, diesel trains and generators.
Black carbon emissions are commonly associated with sooty chimneys and exhausts where there is visible smoke. However, much of the black carbon emitted from modern boilers and engines is in the form of tiny particles which are invisible to the naked eye.
