London's Pulse: Medical Officer of Health reports 1848-1972
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Hints from the Health Department. Leaflet from the archive of the Society of Medical Officers of Health. Credit: Wellcome Collection, London
City of Westminster 1930
[Report of the Medical Officer of Health for Westminster, City of]
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ATMOSPHERIC POLLUTION.—AUTOMATIC AIR FILTER.
Average Monthly-Hourly Readings. Taken at the City Hall.
Degrees of Pollution are calculatedjfrom a standard scale of shade values. One degree corresponds to -54 lbs. of dirt per 1 million cubic yards of air.
Average degrees of suspended matters (mostly dirt) estimated for each month and indicated to show the variations at each hour in the 24 hours. The means are so calculated on this graph to show in convenient form the sum of
pollution throughout the whole month interpreted in terms of a single period of 24 hours.
To face page 78.