Air Pollutants – Sulphur Dioxide

Sulphur dioxide (SO2) is a gas. The molecules of the gas are made up of one sulphur atom and two oxygen atoms.

Currently the largest emitter of sulphur dioxide is electricity power generation from oil and coal burning. The largest sources used to be domestic coal burning and heavy industrial activities like steel making.

img:Sulphur DioxideThese activities gave rise to very high levels of air pollution and, together with smoke, used to form thick, toxic wintertime smogs (a mixture of the words smoke and fog) over towns and cities. In the past, our region suffered greatly from these smogs that were brought about by emissions from domestic chimneys and factories.

During the winter of 1952 a smog pollution episode in London was so severe that around 4 000 people died, with a further 8 000 dying in the weeks and months after it.

Legislation was put in place to stop such a terrible pollution incident from happening again. This resulted in the Clean Air Act being passed. The Act was so successful that today sulphur dioxide levels have declined to well within the UK Government’s targets. There are however places that have higher sulphur dioxide levels than the rest of the country, such as next to busy ports due to shipping emissions, and in areas where there are high numbers of trains idling in heavily used railway sidings.

Sulphur dioxide, like particulates, can affect life expectancy if there is prolonged exposure. It is also a strong irritant and can affect people’s health by causing a narrowing of the airways. There is an association between hospital admissions and deaths on days when sulphur dioxide is high.

How is sulphur dioxide measured?

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