Smog


 * Smog ** is a type of air [|pollutant] . The word "smog" was coined in the early 20th century as a [|portmanteau] of the words [|smoke] and [|fog] to refer to smoky fog.  The word was then intended to refer to what was sometimes known as [|pea soup fog], a familiar and serious problem in [|London] from the 19th century to the mid 20th century. This kind of smog is caused by the burning of large amounts of [|coal] within a city; this smog contains [|soot] [|particulates] from [|smoke] , [|sulphur dioxide] and other components.
 * Smog ** is a type of air [|pollutant] . The word "smog" was coined in the early 20th century as a [|portmanteau] of the words [|smoke] and [|fog] to refer to smoky fog. [|[1]]  The word was then intended to refer to what was sometimes known as [|pea soup fog], a familiar and serious problem in [|London] from the 19th century to the mid 20th century. This kind of smog is caused by the burning of large amounts of [|coal] within a city; this smog contains [|soot]  [|particulates] from [|smoke] , [|sulphur dioxide] and other components.