The London Fogs of November 25–27, 1923

Abstract

THE accompanying graph (Fig. 1) shows the hourly variation in the quantity of suspended impurity, that is, sooty matter, in the air of London (Westminster), which was chiefly responsible for the recent smoke fogs. This curve shows clearly that the maximum density of the smoke fog occurred about mid-day, and there was a rapid increase in density which coincided with the period of lighting up of fires in the morning. The figures from which the curve is plotted were obtained from my automatic recorder, designed for the Advisory Committee on Atmospheric Pollution. When a large number of days are averaged and plotted, the distribution over the 24 hours is similar but more uniform, and it can even be seen that the maximum is reached later on Sundays than on weekdays (Eighth Report Advis. Comm. on Atmos. Pollution, p. 30).