Atmospheric pollution in Leicester : a scientific survey.

  • Great Britain. Atmospheric Pollution Research Board.
Date:
1945
Catalogue details

Licence: Public Domain Mark

Credit: Atmospheric pollution in Leicester : a scientific survey. Source: Wellcome Collection.

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    4:0. VARIATION OF POLLUTION WITH TIME 4-1] INTRODUCTION Two of the most striking characteristics of atmospheric pollution are its variation from place to place and its variation at any one place from time to time. The distribution of pollution in and around Leicester was discussed in Chapter 3. The present chapter deals with the variations of pollution with time which were observed in Leicester. Pollution changes with the same bewildering rapidity as weather; indeed it will be shown to have a close connection with weather. It also varies with the amount of coal burned in houses and factories. The coal burned in houses, offices, and even industrial works is partly dependent on the outdoor tempera- ture, because in cold weather more coal is needed for providing heat. The amount of coal used for making gas or electricity varies according to the many purposes for which the gas and electricity are required; since these purposes include the heating of buildings, there will again be appreciable dependence on weather. On the other hand, the coal used for cooking, for providing hot water, and for power to drive machinery is far less dependent on temperature and weather generally. Table 4:1 summarizes the situation, and it applies to all forms of atmospheric pollution which are derived from coal. The diagram should be read downwards, and every line represents the words “depends on.”’ TABLE 4:1 ATMOSPHERIC POLLUTION 2 | | Quality and amount of coal Combustion conditions used directly or indirectly and draught | San eee | Power Heating and lighting Type and requirements requirements efficiency of equipment Industrial Domestic needs needs lau | HuMAN HapsirTs WEATHER With two exceptions, every item in the above diagram must vary in one way or another with time. The exceptions are combustion conditions and draught, and type and efficiency of equipment. Even these items will vary gradually, but the variations in the three years 1937-9 are unlikely to have made a noticeable difference to atmospheric pollution at Leicester, and may be neglected. ; | 4-11 Types of Variation | , The remaining items in Table 4-1 may vary irregularly, or periodically, o in both ways together. Periodic variations are specified by the time required for a full cycle. The commonest periods are yearly, such as the seasonal varia- tion of weather, and daily, such as the 24-hourly variation of temperature due to the rising and setting of the sun. In addition a weekly period occurs in the
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