Most people perceive the Arctic as a clean, pristine environment, but the Smoking
Hills, located 350 km east of the Mackenzie Delta, are a natural source of air
pollution. The shale rocks in this area are rich in sulphur and coal. A chemical
reaction between these two substances results in spontaneous combustion
the ground is on fire! The Hills have been smouldering for hundreds of years,
emitting columns of thick smoke. Burning sulphur is transformed into sulphur
dioxide, a chemical which has acidified the neighbouring soil and ponds.