ABSTRACT
The increased carbon dioxide content of some smogs caused temporary intensified breathing of cold air and produced pneumonia in some old or very young people. During the infamous London smog of 1952 when the air became very stagnant over London for more than four days, it was estimated that the air contained about ten times the usual amount of carbon dioxide. An average molecule of nitrogen probably stays in the air for several centuries before it is combined into some organic or inorganic chemical compound to be returned to the atmosphere ultimately after a spell of duty in the biological world. Outside, in calm air, pollution is absorbed onto buildings, trees and so on, but more slowly than indoors because there is less solid surface close to a given volume of air. The continual repetition of the misleading statement that the Great Smog of 1952 killed 4,000 people helped the campaign for clean air enormously.
