1. Great Smog Подготовила: студентка 2 курса 2 группы Буслаева Мария
Проверила: Резникова Е. Н.

2. Contents 1 Pre-Events 1.1 Sources of pollution 1.2 Weather
1.3 Effect on London
2 Health effects
3 Environmental impact

3. 1 Pre-Events 1.1 Sources of pollution
The cold weather preceding and during the smog meant that Londoners were burning more coal than usual to keep warm. Post-war domestic coal tended to be of a relatively low-grade, sulfurous variety (economic necessity meant that better-quality "hard" coals tended to be exported), which increased the amount of sulfur dioxide in the smoke.

4. There were also numerous coal- fired power stations in the Greater London area, all of which added to the pollution.
Additionally, there were pollution and smoke from vehicle exhaust — particularly from diesel-fuelled buses, which had replaced the recently abandoned electric tram system — and from other industrial and commercial sources. Prevailing winds had also blown heavily polluted air across the English Channel from industrial areas of Continental Europe.

5. 1.2 Weather
On 4 December 1952, an anticyclone settled over a windless London, causing a temperature inversion with cold, stagnant air trapped under a layer (or "lid") of warm air.The resultant fog, mixed with chimney smoke, particulates such as those from vehicle exhausts, and other pollutants such as sulfur dioxide, formed a persistent smog, which blanketed the capital the following day. The presence of tarry particles of soot gave the smog its yellow-black colour, hence the nickname "peasouper". The absence of significant wind prevented its dispersal and allowed an unprecedented accumulation of pollutants.

6. 1.3 Effect on London
Аlthough London was accustomed to heavy fogs, this one was denser and longer-lasting than any previous fog. Visibility was reduced to a few yards making driving difficult or impossible.
Public transport ceased, apart from the London Underground; and the ambulance service stopped functioning, forcing users to transport themselves to hospital.

7. Near railway lines, on which 'fog working' was implemented, loud explosions similar to the report of a shotgun were a common feature. These explosions were made by 'detonators', a form of large percussion cap placed on the track and activated by the wheels of trains. These were placed by certain signals to provide an audible warning to match the visual indication provided by the signal for the driver.

8. 2 Health effects
There was no panic, as London was renowned for its fog. In the weeks that ensued, however, statistics compiled by medical services found that the fog had killed 4,000 people. Most of the victims were very young or elderly, or had pre-existing respiratory problems. In February 1953, Lieutenant-Colonel Lipton suggested in the House of Commons that the fog had caused 6,000 deaths and that 25,000 more people had claimed sickness benefits in London during that period.

9. Most of the deaths were caused by respiratory tract infections from hypoxia and as a result of mechanical obstruction of the air passages by pus arising from lung infections caused by the smog. The lung infections were mainly bronchopneumonia or acute purulent bronchitis superimposed upon chronic bronchitis.
More recent research suggests that the number of fatalities was considerably greater, at about 12,000.

10. 3 Environmental impact
The death toll formed an important impetus to modern environmentalism, and it caused a rethinking of air pollution, as the smog had demonstrated its lethal potential.
New regulations were implemented, restricting the use of dirty fuels in industry and banning black smoke.

11. Environmental legislation since 1952, such as the City of London (Various Powers) Act 1954 and the Clean Air Acts of 1956 and 1968, led to a reduction in air pollution. Financial incentives were offered to householders to replace open coal fires with alternatives (such as installing gas fires), or for those who preferred, to burn coke instead (a byproduct of town gas production) which produces minimal smoke. Central heating (using gas, electricity, oil or permitted solid fuel) was rare in most dwellings at that time, not finding favor until the late 1960s onwards.

12. Despite improvements, insufficient progress had been made to prevent one further smog event approximately ten years later, in early December 1962.

13. Спасибо, за
внимание!

14. Used resources
Опаловский А.А. Планета Земля глазами химика. М., Наука, 1990
Ревель П., Ревель Ч. Среда нашего обитания. В четырех книгах (перевод с англ.). М., Мир, 1995
Химия и общество (перевод с англ.). М., Мир, 1995