utNowadays pollution is becoming more and more serious problem, particularly air pollution. Since the beginning of the industrial revolution, the chemical elements of the atmosphere have changed. Along with the development of industrialization, air pollution has spread and now it is a global issue. There are many kinds of air pollution, one of them is smog. Smog can come from many areas, particularly factories and transportation systems, but there are some differences between developed and developing countries. In developed countries, highly developed industry is the main reason that smog is serious, they mostly use fossil fuels.
However, developing countries started to industrialize, so increasing number of factories is the most important cause of smog and they always use the coal or wood burning. More and more people using cars and motorcycles also is a reason about that. Those of us who live in large cities are familiar with smog air pollution; the familiar brown haze resting over the city on a still day. We need to know what smog contains and where it comes from, as well as the health and environmental impacts of this hallmark of industrialization.
There are two categories of smog to be covered: classic smog and the more recently described photochemical smog. Classic Smog In its most primitive and basic form, smog air pollution is the result of the burning of fossil fuels. It has several major components: 1) Smoke, which is tiny particles of ash, is released from the smokestacks of coal fired power stations. Coal power plants are now on the whole designed to trap this ash, called fly ash, which can be used to great effect in the concrete industry.
These tiny particles contain not only carbon residue, but also silicon dioxide, calcium oxide and traces of heavy metals. If inhaled these can pose significant health risks. The silicon dioxide in the fly ash alone can cause lesions, scarring and inflammation of the lungs. 2) Sulfur Dioxide. Sulfur is present in all fossil fuels and is released as Sulfur Dioxide when the fuels are burned. Sulfur Dioxide reacts with oxygen gas to give Sulfur Trioxide. This then can react with water to give Sulfuric Acid (H2SO4).
Another possibility is that the Sulfur Dioxide reacts immediately with water to give Sulfurous Acid (H2SO3). Either way, the acid produced is highly reactive and capable of causing significant damage to crops, soil, buildings and more. Several industrialized nations now employ technology that captures approximately a third of Sulfur Dioxide from the emission gases of power stations, greatly reducing the problems of acid rain. Photochemical Smog This is a far more noxious mixture of chemicals than classic smog air pollution. Significant inroads have been made to reduce the main contributors to classic smog.
Such efforts in relation to photochemical smog are still in their early stages. Photochemical smog air pollution is a mixture of various chemicals that react with sunlight to produce new chemicals. This is where the name comes from; photo means light and chemical means chemical, or product of a chemical reaction. The chemical reactions involved are complex and while they are important, we need to know the source of these pollutants and their effects. The chemicals involved need to be addressed separately. The three main ingredients are Nitrous Oxides, volatile organic compounds and Ozone.
Carbon Monoxide is a toxic byproduct of fossil fuel combustion but is considered separate to photochemical smog. London smog disaster One of the famous smog with all bad effects is London Smog which was caused by heavy coal combustion during the winter of 1952, The weather in Greater London had been unusually cold for several weeks leading up to the event because of the cold weather, households were burning more coal than usual to keep warm. The smoke from approximately one million coal-fired stoves, in addition to the emissions from local industry, was released into the atmosphere.
Increases in smoke and sulfur emissions from the combustion of coal had been occurring since the Industrial Revolution and the British were familiar with these types of smog events. At times, the smoke and emissions were so heavy that residents referred to the events as ‘pea soupers’ because the fog was as dense as pea soup. However, while the area had experienced heavy smog in the past, no event had caused such problems as the weather event in December, 1952. Thousands of tons of black soot, tar particles, and sulfur dioxide had accumulated in the air from the heavy coal combustion.
Estimates of PM10 concentrations during December, 1952, range between 3,000 and 14,000? g/m? with the high range being approximately 50 times higher than normal levels at the time. PM10 is particulate matter less than 10 micrometers in diameter. Conditions for Londoners today are much better with PM 10 concentrations around 30? g/m?. Estimates also suggest that sulfur dioxide levels during December of 1952 were 7 times greater than normal at 700 parts per billion (ppb). The 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, sulphurous variety (economic necessity meant that better-quality “hard” coals tended to be exported), which increased the amount of sulphur dioxide in the smoke. There were also numerous coal-fired power stations in the Greater London area, including Battersea, Bankside, and Kingston upon Thames, all of which added to the pollution. Research suggests that additional pollution prevention systems fitted at Battersea may have actually worsened the air quality, reducing the output of soot at the cost of increased sulphur dioxide, though this is not certain.
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. 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, 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. 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. 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. Environmental legislation since 1952, such as the City of London (Various Powers) Act 1954 and the Clean Air Acts of 1956 and 1968, has led to a reduction in air pollution.