Household air pollution, caused by the use of plant-based or coal fuel for cooking, heating, and lighting, is putting nearly three billion people worldwide at risk of ill health and early death, according to a new Commission, published in The Lancet Respiratory Medicine journal.

A third of the world’s population use plant-based solid fuels such as wood or charcoal, or coal, to cook, heat, and light their homes, primarily in Asia and Africa. These smoky, dirty fuels are often used in an open fire or simple stove, resulting in high levels of household air pollution in poorly ventilated homes.

Estimates suggest that household air pollution killed 3.5 to 4 million people in 2010 [1]. Although overall rates of exposure to household air pollution have been declining slowly in recent years, population growth means that the number of people exposed has remained stagnant, at around 2.8 billion people worldwide.