1905: During the last two decades of the 19th century, the amount of coal transported annually to London by rail, sea and canal increased from 10 million to 16 million tonnes. Each day, more than 200 tonnes of fine soot were discharged into the city’s atmosphere. In 1905, Dr. Henry Des Voeux of the Coal Abatement Society merged “smoke” and “fog” to coin a new term for the pollution – “smog”.
Source: Turner Whistler Monet, ed. Katharine Lochnan (2004), pp. 52, 236