Air Quality in Bexley
Bexley Council is responsible for Air Quality Management: monitoring the local air quality and preparing action plans to improve local circumstances. Today, the main influences on air quality are road traffic and the impact of industry.
The quality of the air in Bexley is affected by:
- Industrial / Commercial activity (e.g. gases discharged to the atmosphere from factory chimneys, power stations, etc and dust from building sites quarries, etc)
- Transportation (i.e. fossil fuels used by cars; lorries and aircraft). Pollution from road traffic is often the most significant factor.
- Domestic activity (e.g. gas and oil fired central heating boilers; ‘open fires’ and bonfires)
Bexley borough is a smoke control area. Domestic chimneys
should not therefore emit smoke except under very specific
circumstances. This is what people mean when they are
talking about "smokeless zones". If you want
to burn solid fuel in your home, you should only use fuels
authorised for use within smoke control areas, such as
anthracite, low volatile steam coals and most of the commercial
smokeless fuels. In certain circumstances, it may be possible
to use fuels other than those that have been authorised.
You should only do this if you are using an "exempted
fireplace", operated in accordance with the manufacturer's
instructions and using the fuels specified by the manufacturer.
For a current list of approved solid fuel products, and
exempted fireplaces, please contact the  Heating
Equipment Testing and Approval Scheme (HETAS) or telephone
01242 673257.
Occasionally air pollution, including for example, smoke, fumes, gases, dust
and smells, can occur which interferes with the enjoyment of a property
or is prejudicial to health. Enforcement action can be taken by
the Environmental Protection Team to deal with these situations.
The Environmental Protection Team also set conditions controlling
the operation of over 50 prescribed processes which have the potential
to cause significant air pollution. More
on the Control of Commercial and Industrial Emissions in Bexley.
UK Air Quality Strategy
In 1997, the UK became the first country in Europe to develop an air quality strategy. This has undergone a series of reviews since then and the latest version, The Air Quality Strategy for England, Wales and Northern Ireland, can be found on the DEFRA (Department for Environment, Food and Rural Affairs) website. The Strategy sets out the air quality issues facing the UK, the targets that the Government has set, and policies put in place to attempt to achieve those targets.
Central to the Strategy are the National Air Quality Objectives. Covering eight different pollutants, these objectives include the tolerance level and the concentration, an averaging time over which the pollutant should be measured.
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National Air Quality Objectives
Pollutant |
Objective |
Measured as |
Benzene
|
16.25 µg/m³ |
Running Annual Mean |
|
Benzene
|
5 µg/m³ |
Annual Mean |
1,3-Butadiene |
2.25 µg/m³ |
Running Annual Mean |
|
Carbon monoxide
|
10.0 mg/m³ |
Maximum daily running 8 Hour Mean |
Lead |
0.5 µg/m³ |
Annual Mean |
0.25 µg/m³ |
Annual Mean |
Nitrogen Dioxide |
200 µg/m³
Not to be exceeded more than 18 times per year |
1 Hour Mean |
40 µg/m³ |
Annual Mean |
Nitrogen Oxides |
(V) 30 µg/m³ |
Annual Mean |
Ozone |
100 µg/m³ |
Running 8 hour Mean
Daily maximum of running 8 hr mean not to be exceeded more than 10 times per year |
|
Particles (PM10)
(gravimetric)
|
50 µg/m³
Not to be exceeded more than 35 times per year |
24 Hour Mean |
40 µg/m³ |
Annual Mean |
Sulphur Dioxide |
266 µg/m³
Not to be exceeded more than 35 times per year |
15 Minute Mean |
350 µg/m³
Not to be exceeded more than 24 times per year |
1 Hour Mean |
125 µg/m³
Not to be exceeded more than 3 times per year |
24 Hour Mean |
(V) 20 µg/m³ |
Annual Mean |
(V) 20 µg/m³ |
Winter Mean (01 October - 31 March) |
One of the main components of the UK Air Quality Strategy is Local Air Quality Management (LAQM). Since 1997, all Councils (other than county councils) have been assessing the air quality in their area and, where a problem is found, developing action plans to address the situation.
Under LAQM, Councils must investigate the levels of pollution in their area. They do this in a number of ways. The most obvious is to measure concentrations of the main pollutants directly, using monitoring equipment. However, this equipment is often expensive and, in order to obtain good quality data, usually needs to stay in the same place for long periods of time. This means that monitors cannot give a complete picture of an area, and so mathematical computer models are used to predict what the air quality would be like in other areas, based on measurements and known sources of pollution, such as roads and industrial plant.
Models can also be used to help predict trends in pollution levels, and the effects of different weather conditions and source activity patterns (such as traffic levels, vehicle types, etc). In this way, air quality models can be used to assess whether or not the National Air Quality Objectives are likely to be breached in their target year. This process of monitoring, data collection and predictive modelling is known as "review and assessment".
If after carrying out review and assessment, a local authority finds that one or more of the National Air Quality Objectives is likely to be breached, it is obliged by law to declare an Air Quality Management Area.
Once an authority has declared an Air Quality Management Area, it must then develop an Action Plan, which sets out how it uses the powers at its disposal in pursuit of the National Air Quality Objectives. It is important to note that Councils are not actually obliged to achieve the objectives, as they do not have sufficient control over all of the sources that could potentially give rise to the breach. For example, major roads and motorways are usually under the control of the Highways Agency, and large industrial processes, including power stations, are regulated by the Environment Agency. Councils have no powers to direct either body, although the Environment Agency has given a commitment to assist where industry is the main cause of the breach. The great majority of Air Quality Management Areas have been declared because of emissions from road transport.
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The Main Sources of Air Pollution
These are the main pollutants and where they come from.
Particulate Matter (PM10)
The principal source of PM10 in European cities is road traffic emissions, particularly from diesel vehicles. It is also emitted from industrial combustion plants and public power generation, commercial and residential combustion, and some non-combustion processes (e.g. quarrying). Natural sources include volcanoes and dust storms, but these sources produce only a small percentage of fine particulate matter. Levels are highest in urban areas as it is a traffic-related pollutant.
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Nitrogen Dioxide (NO2)
Nitric oxide (NO) is produced during high temperature burning of fuel (e.g. road vehicles, heaters and cookers). When this mixes with air, NO2 is formed. Levels are highest in urban areas as it is a traffic-related pollutant.
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Ozone (O3)
Ground level ozone is a secondary pollutant; it is formed through a chemical reaction of volatile organic compounds and nitrogen dioxide in the presence of sunlight. As this process is dependent on sunlight, levels are higher in the summer. The reactions can take some time during which the polluted air has drifted many miles. The highest levels tend to be found in rural areas down wind of urban or industrial areas.
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Sulphur Dioxide (SO2)
Fossil fuel combustion (principally power stations), conversion of wood pulp to paper, manufacture of sulphuric acid, smelting, incineration of refuse. The most common natural source is volcanoes.
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Volatile Organic Compounds (VOCs)
Benzene
The main source of atmospheric benzene in Europe is combustion by petrol vehicles, which accounts for about 70% of emissions. Another 10% comes from the distillation, refining and evaporation of petrol from vehicles.
Other VOCs play a role in the photochemical formation of ozone in the atmosphere.
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1,3-Butadiene
The main source of 1,3-Butadiene is also principally from road traffic, in the combustion process of petrol and diesel vehicles. Unlike benzene it is not a constituent of fuel but is produced through the combustion of olefins. An additional source is from industrial processes such as synthetic rubber manufacture.
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Carbon Monoxide (CO)
CO forms where carbon fuels are burned, either in the presence of too little oxygen or at too high a temperature. One main source is idling vehicle engines and vehicle deceleration. Smaller amounts are released into the atmosphere from organic combustion in waste incineration and power station processes. Levels are highest in urban areas due to its close association with road traffic. However, in the UK levels are generally low, well below the targets set by the Government.
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Lead (Pb)
As much of the airborne emission of lead originates from road traffic, concentrations are decreasing with most cars running on unleaded and lead replacement petrol. Other sources of lead pollutants include waste incineration and metal processing. The largest industrial use is manufacturing batteries.
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Toxic Organic Micro-Pollutants (TOMPs)
PAHs (Polycyclic Aromatic Hydrocarbons), PCBs (Polychlorinated Biphenyls), Dioxins, Furans
Produced by the incomplete combustion of fuels, road transport
and industrial plant are the largest source. Open burning is a major source
in the UK and comparatively large amounts are released on and around bonfire
night. Tobacco smoke is also a source.
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