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How bad are winter smogs?

In the past winter smogs, known as ‘pea-soupers’, would have been caused by the burning of huge quantities of domestic and industrial coal. Fortunately, since the availability of mains natural gas, the Clean Air Acts of 1956 and 1968, and the subsequent, more stringent air quality targets, these episodes have been greatly reduced. Modern winter air pollution episodes are now driven by pollution from road transport, and although they are less visible they are still of concern.

Winter smogs are formed when a thin layer of the atmosphere near the earth becomes cooler than that above it – this is known as temperature inversion. When this happens pollutants are trapped at ground level until there is a change in the weather.

Health experts believe that winter smogs may result in a rise in premature death as well as a rise in respiratory and heart-related problems. These conditions often affect those with chronic obstructive pulmonary disease (COPD), because of the combination of poor air quality, cold temperatures and more coughs and colds during the winter season.

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