Firing up an air pollution problem

Millions of tonnes of toxic gases and smoke particles are spewed into the atmosphere by forest fires and other wildfires every year, making them a major source of global air pollution.  These emissions have a major impact on global human health. The 2015 haze across Asia, caused by an anomalous year of fires in Indonesia, was estimated to cause over 100,000 premature deaths in the region.

We look at some of the efforts to understand how much of a problem this is, and the chemistry in the complex smoke produced.