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Clean Air in the UK

Introduction

The quality of the air in the UK has improved dramatically over the past century. The smogs of the early 1900s no longer occur due to declining levels of sulphur dioxide and smoke pollution. However, at times there can be episodes of air pollution which can cause high levels of pollutants and can be harmful to human health and the environment. There are various factors which affect how and where high levels of pollution are found which makes identifying places with 'clean air' difficult. The Air Quality Strategy for the UK has been set to ensure that air quality continues to improve thoughout the UK.

Air Quality Monitoring

Monitoring of air pollution occurs in hundreds of locations throughout the UK. Many of these sites are in towns and cities, representing areas where large numbers of the population reside. Other sites monitor pollution levels in rural and more remote parts of the countryside. There is access to this data on Ceefax (p410-417) and Teletext (p106), the Internet (www.environment.detr.gov.uk/airq/aqinfo.htm) and via a freephone telephone information line (0800 556677) which are all updated daily. Local authority Environmental Health departments will also know about air pollution in their area.

Where is the Air Cleanest?

There are many factors that affect air quality, making the search for clean air quite a complicated issue. This is because air pollution enters the atmosphere by different amounts at different times and in various places. Air pollutants may also change in the atmosphere to make other pollutants. In addition, people can have differing sensitivities to air pollutants. For example, the elderly, the very young and those with asthma or other breathing difficulties are likely to be more sensitive to high levels of pollutants. The main factors affecting air pollution levels are highlighted below.

Topography

Concentrations of pollutants can be greater in valleys than for areas of higher ground. This is because, under certain weather conditions, pollutants can become trapped in low lying areas such as valleys. This happens for example, on still sunny days when pollution levels can build up due to a lack of wind to disperse the pollution. This can also happen on cold calm and foggy days during winter. If towns and cities are surrounded by hills, wintertime smogs may also occur. Pollution from vehicles, homes and other sources may become trapped in the valley, often following a clear cloudless night. Cold air then becomes trapped by a layer of warmer air above the valley.

Weather Conditions

The weather has an important effect on air pollution levels. Generally, windy weather causes pollution to be dispersed whilst still weather allows pollution to build up. Coastal locations and open areas often experience more windy weather and are therefore likely to experience better air quality. The wind direction also affects air pollution. If the wind is blowing towards an urban area from an industrial area then pollution levels are likely to be higher in the town or city than if the air is blowing from another direction of for example, open farmland. Sunshine can also affect pollution levels. On hot, summer days, pollution from vehicles can react in the presence of sunlight to form ozone. The pollution that causes ozone to be formed is usually generated from vehicles in cities and towns but because this pollution can be transported by winds, high levels of ozone may be found in the rural countryside. The pressure of the air also affects whether pollution levels build up. During high pressure sytems, the air is usually still which allows pollution levels to build up but during low pressure systems the weather is often wet and windy, causing pollutants to be dispersed or washed out of the atmosphere by rain.

Exposure to Pollution

There are many sources of pollution, both indoor and outdoor which can have affect health. Research has shown that air pollution inside moving cars in heavy traffic is around twice as high as that outside the car. However, air pollution decreases rapidly as you move away from busy roads. Levels of air pollution 10-15 metres away from busy roads are generally half of the roadside concentration and a further 30-40m away they are halved again. Air pollution is also often concentrated in underground car parks, tunnels and near petrol stations. Levels of air pollution are also likely to be higher in the vicinity of industrial processing works, power stations and waste incineration plants.

Time

Pollution levels vary over time. Variations occur throughout the day and over seasons depending on weather conditions and emission sources. Often in urban areas, rush hour traffic cause emissions of vehicle pollution to peak in the early morning and evening to correspond with high levels of traffic and congestion. Some pollutants are emitted in greater amounts during the winter season due to the increase in use of fuel for domestic and industrial heating.

Pollution Emissions

Some pollutants are more heavily concentrated in different areas depending upon emission sources. For example, areas where solid fuel is heavily used for domestic heating such as Belfast or south Yorkshire are likely to have higher emissions of sulphur dioxide pollution. Motor vehicle pollution can generate high levels of nitrogen dioxide, carbon monoxide and hydrocarbons in cities and towns. Particulate pollution may be high as a result of vehicle pollution, fuel burning, building work, industrial emissions, soil and road dust and quarrying. Pollution emissions in other countries can also be transported across international borders to create high levels of pollutants such as ozone.

Conclusion

There are many factors affecting air pollution levels in different parts of the UK, as highlighted in this leaflet. If you are searching for somewhere to live where air quality is an important consideration, you may wish to look for a home that has a relatively open aspect (where air changes more frequently) and is situated away from major sources of pollution such as industrial processing plants, busy roads, quarries, petrol stations and incinerators.