Smoke

Smoke

Smoke is caused by the incomplete burning of fossil fuels, such as coal. It is a health hazard on its own but even more dangerous if combined with fog. This poisonous combination, called smog, was prevalent in the early 1950s. It formed in its highest concentrations around the large cities where many domestic coal fires were then in use. Many deaths were recorded, especially among the elderly and those with respiratory diseases. This led to the first Clean Air Act, which prohibited the burning fuels that caused smoke in areas of high population. So-called smokeless zones were established.