GG3068: Atmospheric Pollution

Lecture 8 Air Pollution: Solutions and Prospects


Pollution Control in the UK

The adverse health effects of air pollution (such as increased incidence of bronchitis) were realised in Britain from around the 1840s, and several attempts were made to introduce laws to require owners of furnaces to reduce smoke emissions. These attempts were resisted by industrialists (well represented in Parliament) until industry realised that there were economic reasons for reducing pollution (that is, excessive air pollution represented wasted fuel). The first pollution control Act was the Smoke Nuisance Abatement (Metropolis) Act in 1853, although effective efforts began with the Alkali Act (1863). At the time, severe problems were experienced near industrial plants manufacturing alkalis such as sodium carbonate and sodium hydroxide: emissions included hydrogen chloride, which was converted into hydrochloric acid in the atmosphere, causing extensive damage to vegetation. The Alkali Act required that 95% of the emissions should be arrested, and the remainder diluted. This simply meant passing the acid vapours through water, but this had a dramatic effect: prior to the Act, emissions from Alkali works were almost 14,000 tonnes annually, but after it came into force this was reduced to only 45 tonnes. A second Alkali Act followed in 1874, requiring industrialists to apply the best practicable means to tackle pollution problems. This Act provided the foundation of air pollution policy in the UK for the next 100 years. The Alkali Acts, and their successors, are enforced by an Inspectorate (named Alkali and Clean Air Inspectorate until 1982, and the Inspectorate of Pollution since 1987). The Inspectorate was not very effective throughout most of the 20th Century: between 1920 and 1967 there were only 3 prosecutions under the Act. Even 1970-1975, a time of much increased environmental awareness, there were only 20. Partly, this was due to a very liberal interpretation of the law, which stated that industry must use the best practicable environmental option, or the best available techniques not entailing excessive cost to control emissions.

Media response to the Great London Smog of 1952 galvanised opinion in favour of stronger pollution control. Earlier smogs had been as severe, but were not a media issue. This pressure forced the Gorvernment to take action, and a committee was set up to examine the problem of air pollution. The committee proved very critical of Government policy, and a new Clean Air Act was introduced in 1956. This Act granted local authorities the power to designate smoke control areas in which only authorised smokeless fuels (e.g. anthracite, electricity, gas and oil) could be used (this followed a model already introduced by some progressive authorities such as Manchester and Coventry). 40% grants were made available to householders to allow them to replace coal fires with gas or electrical heating. The implementation of the Act was uneven: larger, wealthier authorities (e.g. London, Yorkshire) adopted progressive programmes, while others were slow to respond. Ironically in coal-mining areas, there was strong resistance: miners received a concessionary coal allowance, and designation of smoke control areas would restrict its use. It was also feared by miners that pollution control would damage the industry and cause redundancies.

Due to the uneven response to the Clean Air Act of 1956, a stronger Clean Air Act was introduced in 1968, which required local authorities to take action to designate smoke control areas. However, progress was frequently interrupted, such as 1970-1 when many control areas were suspended due to fuel shortages, leading to worsening air pollution episodes in some areas. Nevertheless, a huge shift occurred in the type of fuels used for domestic heating and cooking. Prior to WWII, dwellings relied almost excusively upon coal fires for heating and cooking, resulting in very high pollution output. Switching to gas, electricity, or processed smokeless coal brought about significant reductions in urban pollution. Switching to electricity meant that local pollution was negligible, because the power was generated elsewhere, whereas domestically burned oil, gas and smokeless coal produced much less particulates and sulphur than before. These trends were not simply due to legislation: they were also largely due to changing social aspirations at the time, and the availablity of clean, easy options for domestic heating and cooking that were much preferable to lighting coal fires or stoves.

Similar trends had already occurred within industry: in the 19th C, most industries generated their own power from coal, and this changed as centrally generated power took over. Pollution from industrial processes (e.g. chemicals, metal smeting, paper production), however, continued to be generated by factories. Legislation was effective in reducing black smoke (particulates), and local acidification by setting minimum heights for stacks. However, long-distance air pollution and acid rain were actually increased by the tall stacks policy.

Pollution from power stations can be reduced by several means.ignificant improvements in emission levels can be achieved through cleaner power stations. Treatment can be before, during or after combustion. Fuel switching: replacement or blending of high sulphur coal with low-sulphur coal, or switching to oil or gas or renewable sources. Shifts from domestic fossil fuel to fossil-fuel electricity generation may simply relocate the problem. Economic constraints due to availability of fuel or type of power station: blending is the most common strategy. Fuel desulphurization: removal of some sulphur before combustion. Crushing and washing can reduce SO2 by 8-15%: a reduction of 1.5 to 2 m. tonnes yr-1 has been made in the US alone. More effective & complex chemical cleaning can be done but is expensive. Reduction during combustion: basically by burning coal in the presence of lime, which fixes sulphur. Not widely applied so far, but new technologies are promising: Lime Injection Multi-Stage Burning (LIMB) is the injection of fine lime into combustion chamber, fixing sulphur, reducing emissions by 35-50%; Fluidized Bed Combustion (FBC): air under pressure is injected into fine mixture of coal, lime and sand, until whole mass behaves like a boiling fluid. Very efficient combustion, reducing sulphur emissions by 90%. Also reduces NOx because combustion temps. are relatively low.

Flue Gas Desulphurization (FGD or scrubbers) removes sulphur from emissions after combustion, either by passing them through a powdered lime filter (dry scrubbers) or an alkaline liquid (wet scrubbers). Many systems achieve reduction by 80-95%. Can easily be fitted to existing stations (retro-fitting): one of main methods adopted in US, Japan and Europe.In 1999, the UK Environment Agency introduced new controls on emissions from power stations, which requires that by September 2005 the total amount of SO2 to be released from coal- and oil-fired stations in England and Wales is less than 398,000 tonnes: a reduction of approximately 60 percent over 1996/97 rates. This target is to be achieved mainly by the installation of FGDs. Drax, Yorkshire. use of the plant had been discontinued in early 1998National Power, the operators of Drax, have applied to the Environment Agency, for permission to raise emissions of sulphur dioxide from Drax from 100,000 to 270,000 tons per year.

Most cost-effective overall are FBCs, but require building of new plants, rather than adaptation of existing ones. RJB Mining, Texaco and National Power are proposing to build the UK's first 'clean coal' power station at a site adjacent to Kellingley Colliery, West Yorkshire. The proposed 400 MW Integrated Gasification Combined Cycle (IGCC) power station will generate enough electricity to supply a city the size of Sheffield. Pollution from the power station will be a tiny fraction of that from the traditional coal-burning power stations. The two main by-products from the power station will be slag and pure sulphur. The slag will be a non-leachable, glassy substance which will find a market amongst local concrete block manufacturers. Sulphur will be sold to chemical companies in the UK.

The only way to eliminate emissions altogether is to discontinue smelting and fossil fuel burning, with a large-scale shift to cleaner sources (e.g. wind, solar). The British Government has been very slow to embrace such Green alternatives, such as wind power, and this had been exacerbated by a Nimby attitude to wind turbines. However, the present government has set a target that Plans have been announced for 18 large offshore windfarms around the coasts of England and Wales. At present, there are only two offshore wind turbines in use in Britain, which are about half a mile out to sea from the Northumberland town of Blyth. (

The promotion of nuclear power was done partly on environmental grounds, although problems of radioactive pollution and waste management, together with decomissioning costs, have severely reduced the attractiveness of this option, and no new reactors are planned in the UK or USA.

Mobile Sources

Dealing with pollution from vehicles is in many ways much more problematic than stationary sources. Whereas power stations are large, single sources which are recognized by the public as pollution sources, cars are more difficult to deal with. Car use is strongly linked to personal freedom and economic activity, and each user represents only a small portion of the pollution total.

Technological solutions: Most pollution is associated with old, inefficient vehicles. The use of catalytic converters (which remove many pollutants, and break up NOx into N and O before they leave the car) and fuel injection systems, ensure more efficient combustion. Use of such measures in California ensures that most cars emit 10% of main pollutants (CO, NOx, Hc) compared with 1960s. Despite this, Los Angeles still failed to meet air quality guidelines of California Air Resources Board on 200 days in 1990. Emphasis is now on cleaner petrol with oxidizing agents (converting CO to CO2) and a new generation of low emission vehicles (LEVs). The first dual fuel cars (petrol and the less polluting gas) are now on the market, but are still beyond the price range of many people. Another technical possibility is the electric car: success depends on improved technology, particularly batteries.

The only real solution to problem lies in reducing car numbers (with added benefits of reducing work hours lost to congestion, and accident figures). This will, however, be an unpopular transition. Significant reductions in pollution from car use will therefore ultimately depend on transport policies: including provision of convenient, cheap public transport provision. E.G. the Los Angeles metro. There is a pressing need for integrated policies in which public transport is comparably cheap and convenient. Emerging UK transport policy. For the first time, the UK Government has recognised need for integrated transport policy to address pollution and congestion problems, however, progress has been disappointing in the years since its launch. The current wave of petrol price increases are part of this policy, but they have provoked popular protests and a partial climb-down by government. Pollution from traffic will continue to be a major environmental issue in the coming decades.

Findhorn Foundation: an example of an ‘Ecovillage’

A radical, holistic approach to meeting energy needs by cleaner means is being pursued at a number of experimental communities or ecovillages worldwide. Ecovillages is the collective name for intentional communities with aim of trying to apply ecological principles to living. Several such communities developed more or less independently during 1960s -1980s.

Definition: An eco-village is a human scale, full-featured settlement which integrates human activities harmlessly into the natural environment, supports healthy human development, and can be continued into the indefinite future. (Robert Gillman, Context Institute)

Eco-Villages are an integrated solution to the global social and ecological crisis, and are as appropriate to the industrialised world, both urban and rural, as to the remaining two thirds of the world. Eco-villages are in essence a modern attempt by humankind to live in harmony with nature and with each other. They represent a  leading edge in the movement towards developing sustainable human settlements and provide a testing ground for new ideas, techniques and technologies which can then be integrated into the mainstream.  The need for developing sustainable human settlements relates directly to the commitment by the world leaders at the Earth Summit in Rio (1992) to programmes that will move humanity to sustainability in the 21st century (Agenda 21). To achieve the goals of sustainable human settlements, there is a need for pilot communities, and for an exchange of information between them and the mainstream. (Gaia Trust)

There is one ecovillage, the Findhorn Foundation, in the UK, near Forres, Moray. The Findhorn Community (not to be confused with Findhorn village, a nearby coastal village) was established in the early 1960s by Peter and Eileen Caddy and Dorothy McLean as spiritual centre and organic garden. The community grew in many directions in the following years while maintaining its spiritual core. In the last few years, the Findhorn Foundation has developed into an Ecovillage, or working example of a low-environmental impact community. There are several aspects to the ecovillage project, many of which are directly applicable to issues raised in this course.

Buildings with low environmental impact. The main site (‘The Park’) features many low-environment impact homes and other buildings, which have several energy-saving features. These include: triple glazed windows and well-insulated but breathable walls, which retain warmth but help maintain healthy air quality. Passive and active solar features, to gather and generate power. Shared heating boilers, conserving fuel. Natural building materials, reducing indoor pollution by VOCs. Ecological features have also been retrofitted to existing buildings on the site. However, many residents still occupy poorly insulated caravans. Energy efficient buildings reduce the need for power, and consequently reduce the associated pollution problems. The use of local materials in buildings reduces pollution and road congestion associated with transport.

Energy production: A 75 kW wind turbine generates about 10% of the electricity used on site. A new 250 kW windpower scheme planned. Wind and solar power do not contribute greenhouse gases or air pollutants to the atmosphere, and are thus a much healthier alternative to fossil fuels.

Waste water treatment: Living Machine: pioneering organic sewage treatment plant.

Recycling: glass, aluminium, organic waste, paper are all separated and sent to recycling facilities.

Living quality: bright, spacious buildings. Shared spaces: community centre and Universal Hall.

In ecovillages worldwide, the shared. core values differ: some are based on technology, some on community and social issues, and others have a more overtly spiritual focus. All share the common factor of attempting to live lightly and in greater harmony with the Earth The Findhorn Foundation is part of the Global Ecovillage Network. GEN is coordinated by Gaia Trust in Denmark, and has three components: GEN Europe; GEN Oceania and Australia; Ecovillage Network of the Americas.  

Internet Resources

Valuable backround information can be found at the following websites:

Findhorn Foundation

Gaia Trust and Global Ecovillage Network including links to ecovillage projects worldwide

Context Insitute: forum for discussion on sustainability. A wide range of very useful articles from the journal In Context are available online.

Centre for Alternative Technology. CAT in Wales is one of the most important working examples of low-impact technology anywhere in the world. Visit this site for a virtual tour of the centre and much more.    

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