We tend to imagine that as a pollutant soot disappeared with coal fires and the Clean Air Act of the ‘50s.
In fact soot – microscopic particles of unburnt carbon – is thought to be the second largest cause of global warming after carbon dioxide emissions.
Now a study by NASA’s Goddard Institute for Space Studies suggests that reducing soot emissions would have an immediate cooling effect on global temperature, and would help reduce ill-health and deaths from air pollution as well.
Soot contributes to global warming because it darkens snow and ice, reducing its ability to reflect sunlight.