The History Of Air Pollution

Pictures: Great Smog of London London 1952

Accounts about air pollution date back to the 13th Century. Early occurrences resulted from:

• Rapid population growth,
• Urbanisation and changes in fuel use – the medieval switch from wood to coal, especially in brick kilns and domestic fireplaces was the main source of air pollution until the 1950s, then smoke and Sulphur Dioxide (SO2) the main pollutants.
• Coal combustion in industrial furnaces, boilers
• Domestic fireplaces. During calm, cold winter weather, pollutant concentrations could cause severe pollution episodes, termed smogs (smoke + fog), where the combination of smoke and SO2 emissions forms a thick fog, leading to serious health problems. Such pollution episodes occurred as early as the 17th century but, with rapid industrialisation became more frequent and more severe towards the end of the 19th century. Legislation at this time focused only on smoke abatement from industry, and difficulties in implementation led to little improvement in air quality until the early 20th century. Across the UK, episodes of extremely poor urban air quality occurred less frequent from around 1900, as industry and residential areas moved from the centre of cities. A trend towards using town gas and electricity also contributed although the use of coal in their production inevitably involved emissions somewhere. However, pollution episodes such as the Great Smog still occurred, and not only in London. This caused severe and widespread health impacts and great public concern leading to the Clean Air Acts of 1956 and 1968. These acts regulated domestic sources for the first time and introduced ‘smoke control areas’. The focus was purely on smoke from coal; SO2 emissions were not directly regulated, although subsequently, these dropped in parallel with smoke levels. Since the 1960s,
• The burning of cleaner fuels (especially natural gas),
• The decline in heavy industry and the location of power stations with high stacks outside cities has led to an over 90% decrease in national average smoke and SO2 levels.

The 1952 London major smog event led to approximately 12,500 deaths and substantial increases in respiratory illness.This public health toll was the most significant amongst the many reported smog events in London’s history that stretch back over many centuries.Its impacts on health were profound and such was the public response to the problem that political action to ensure it could not be repeated was inevitable. Private members bill, Beaver Committee whose recommendations ultimately resulted in the Clean Air Act, 1956.

Catastrophe drives action. Creates a willingness to act.
However good intentions fall foul of vested interests.
Source: University of West England; Bristol

The Act banned dark smoke emissions from:

• Chimneys,
• Railway engines and vessels,
• Required new furnaces to be smokeless, required the emissions of grit and dust from furnaces to be minimised and gave local council’s powers to introduce smokeless zones.
• The Clean Air Act helped the UK achieve a world leading position in the battle against air pollution.
• However, the importance of sustained interest became apparent later on as elimination of “pea soupers” created a prevailing ideology that air pollution had been conquered.
• Resources were directed towards other problems as governmental priorities changed.
• Late 1980s and early 1990s – a growing public health concern related to childhood asthma and an association with traffic emissions.
• The Environment Act of 1995 and the National Air Quality Strategy, 1997 provide the foundations for what promised to be a sustained and concerted attempt to manage air pollution and to reduce it below levels considered to be a risk to public health.
• The onset of health-based concerns about the impacts of the growth of road traffic in the 1980s and 1990s left the UK woefully ill prepared to tackle a new form of air pollution.