Noise Action Planning in the UK

Now that the first noise maps have been produced, Government are working on the first noise action plans. Managing transport noise is a long term process – there are no instant solutions.

There will be separate plans for major road and rail networks identifying areas for further analysis and, where appropriate, the development of measures to manage noise, including noise reduction if necessary, over the five year life of the action plans. Similar plans will be drawn up for each of the mapped urban areas, which will also include measures that aim to protect those open spaces providing significant and important benefits because they are quiet. Separate plans for each airport currently mapped are being drawn up by the airport operators. All plans are subject to a formal public consultation before submission to the European Commission.

How Can the Impact of Transport Noise Be Reduced?There are many ways in which the noise we hear from transport can be reduced. For aircraft, vehicles and train rolling stock, international standards cover the noise from individual vehicles and some components. Other ways noise can be managed are through looking at how, when and where transport is operated (noise has a greater impact at night). Below are some of the measures that can potentially be used in noise action planning:

1. Speed.For road traffic, reducing speed reduces noise from engines, acceleration and tyres on roads. Sticking to speed limits and lowering speed limits (and ensuring they are enforced) can mean less noise. Managing speed on railways can also reduce noise. Speed restrictions need to be balanced against the impact of increased journey times.

2. Night Time Restrictions.Rerouting heavy lorries away from noise sensitive areas – especially at night, reduces peak noise incidents and therefore potential sleep disturbance. Similarly, restrictions on night flights in and out of airports reduces sleep disturbance, and train horns should not be sounded at night, except in emergencies.

3. Quieter Buses.Modern buses are generally much quieter than older vehicles. Renewing vehicle fleets generally means quieter and cleaner vehicles.

4. Quiet Traffic Calming.Traffic calming is designed to reduce speed – which in theory should reduce noise. However, poorly designed speed humps and chicanes, together with inappropriate driving style can increase noise as drivers brake and accelerate. Measures which encourage smoother driving, such as mini roundabouts and interactive speed signs are more successful.

5. Noise Barriers.These are expensive and can be unattractive, but where a major road or railway runs close to homes noise barriers could be the best option. Their size and composition are determined by location (and cost). Tunnels shield noise but are very expensive to construct.

6. Sound Insulation.Where buildings are exposed to noise, double glazing can be used to reduce the level of noise reaching the inside. This means alternative ventilation methods must be in place so that windows can be kept closed. Also, buildings should be designed to ensure that the most sensitive rooms – such as bedrooms, are on the quietest facade of the building.

7. Quieter Transport Routes.Measures to maintain and improve the quality of road surfaces can reduce noise. Poorly maintained roads and those that have been dug up and patched by utility companies can be noisy. Quieter road surfaces are available but some types can be expensive. In 2007/08 the Highways Agency resurfaced just over 1000 lane km in England with quiet surfaces. For railways, ensuring tracks are well maintained should help minimise noise.

8. Traffic Management.Keeping traffic away from people reduces the noise impact – for example park and ride schemes, pedestrianisation and car free housing areas. Designing urban streets to encourage slower, smoother driving and ensuring smooth traffic flows helps. When flight paths are reviewed noise impact on populations and existing quiet areas should be considered. For rail, noise mitigation should be built into any new routes.

9. Vehicles.Vehicles themselves make noise – engines, exhausts, acceleration and braking. At speeds of around 20mph on congested city streets engine noise may dominate. Although there are European standards for vehicle noise – the trend for bigger noisier vehicles and more traffic means noise has increased in some areas. Work is underway towards tighter standards but progress is slow. However, quiet electric and hybrid vehicles have concerned cyclists and pedestrians who can't hear them coming – and some manufacturers are researching ‘acceptable’ noises for these!

10. Tyres.Rolling noise from the contact between tyres and road surfaces is a major source. An increasing body of research shows that reducing tyre noise is more cost effective than noise barriers and sound insulation. Although quieter tyres are available, heavier, faster vehicles need heavier duty and consequently noisier tyres. EU regulations on tyre noise and noise labelling for tyres will have some impact as will encouraging fleet operators and drivers to choose quieter tyres.

11. Aircraft.There are international noise standards for aircraft, with an ongoing programme for noise reduction.

12. Train Wagons.For trains, newer wagons are quieter, and EU incentives are planned for rail companies to retrofit wagons to reduce noise.

(http://www.environmental-protection.org.uk/noise/environmental-noise/transport noise/#wa2218)

What Can You Do?

Some measures to reduce transport noise require changes in international and national laws, and in the planning and operation of transport systems. However, as transport users we can all make a contribution to reducing noise. Most measures that reduce noise also reduce air pollution and are better for our health and the quality of the local environment, and some reduce fuel use and save money.

Walk or cycle for short journeys

Use public transport

Stick to speed limits

Keep vehicles well maintained – this will save fuel too − keep silencers in good order − check brakes are properly adjusted

Drive smoothly

Don't rev the engine

Turn off the engine when stationary

Keep the music down

Don’t slam doors or sound the horn unnecessarily

Choose quieter tyres

(http://www.environmental-protection.org.uk/noise/environmental-noise/transport noise/#wa2220)

Ozone Pollution

Ozone (O3) is a positive or negative presence in our atmosphere, depending on where it is found. The atmosphere of the earth is divided into four layers, defined by their distance above the planet's surface, with ozone important in the two lower levels − the stratosphere and the troposphere. In the troposphere − the level that contains the air we breathe − ozone is a damaging pollutant. In the stratosphere − 15 − 50 kilometres above the ground − ozone forms a protective layer which filters out the harmful rays of the sun.

Tropospheric ozone.Ozone (O3) occurs naturally in the troposphere (the lowest layer of our atmosphere − 8 − 16km above the surface of the earth) and the stratosphere (the second layer of the atmosphere − 12 − 50km above the earth). The background level of tropospheric, or ground level, ozone is 10 − 30ppb. However, in Europe it is thought to be increasing by 1 − 2% a year due to the effects of pollution. Higher concentrations of ozone can be damaging to plants, animals and materials. Tropospheric ozone is also a greenhouse gas, contributing to global warming.

Ozone pollution.Ozone is a secondary pollutant formed by the action of sunlight on primary pollutants − these are nitrogen oxides from vehicle emissions and industry and volatile organic compounds from vehicles, solvents, paint and industry. Nitrogen oxides react in sunlight (photochemical reaction) to form ozone − a major constituent of photochemical smog. Other constituents are PAN (peroxyacetylnitrate) and aldehydes.

Ozone Formation.The atmospheric chemistry involved in ozone formation is complex. Ultraviolet (uv) radiation from the sun breaks down nitrogen oxide (NO2) into nitrogen oxide and atomic oxygen −

NO2 + uv - NO + O

Oxygen atoms combine with oxygen molecules to form ozone −

O + O2 - O3

However, ozone will not accumulate when nitrogen oxide is present, as the two molecules react to reform nitrogen dioxide and oxygen −

NO + O3 - NO2 + O2

Problems occur when volatile organic pollutants (VOCs) such as hydrocarbons, react in the atmosphere to form oxygenated products such as aldehydes. The oxygen in these molecules allows NO to form NO2, without breaking down ozone, thus ozone accumulates. The build-up of ozone therefore depends upon the relative concentrations of nitrogen oxides, hydrocarbons and other pollutants, and sunlight. It takes time for the ozone to accumulate as the chemical reactions involved are quite slow − ozone builds up in polluted air masses. This takes several days and is favoured by prolonged sunny weather and low windspeeds. Polluted air masses often come from continental Europe, so ozone episodes are more frequent in southern England.

The distribution and build up of ozone is also affected by air movement. Although most of the pollutants that form ozone (ozone precursors) are generated in urban areas, concentrations of tropospheric ozone tend to be higher away from towns. Ozone levels are also higher on high ground and on the coast. For this reason ozone monitoring stations are situated in the countryside as well as in urban areas.

Effects of ozone pollution.Ozone is an unstable oxygen molecule and therefore a strong oxidising agent. It is very reactive and can impact on health. Elevated concentrations can cause eye, nose and throat irritation, chest discomfort, cough and headache. People who exercise or suffer from bronchitis, respiratory allergies or asthma are particularly at risk.

Ozone is also damaging to crops − peas, beans, spinach and wheat are all particularly susceptible. It can affect crop yields and tree growth. It also damages materials such as rubber, paint and textiles. Material damage is related to long term exposure to ozone rather than severe episodes. As ozone is very reactive with all surfaces, it is unlikely that high concentrations will be found indoors.

Reducing ozone pollution.Ozone levels in the air are dependent on atmospheric conditions, as well as pollutants, and ozone can travel on air masses. Therefore reducing pollution requires action at international level to reduce ozone precursors (the pollutants that form ozone). Guidelines for levels of ozone in the air, to protect health, and vegetation have been set by several bodies.

World Health Organisation.As the long term chronic health effects of ozone are uncertain, the recommended WHO air quality guideline is 100 µg/m3 over 8 hours.

EU Ozone Thresholds.Directive 2002/3/EC relating to ozone in ambient air, came into force in 2002; with measures for its implementation had to be in place by September 2003.

Under the Directive Member states must identify zones and agglomerations where these values and objectives are unlikely to be met and draw up action plans or programmes. It also requires that monitoring information is available to the public.

UK Air Quality Guidelines.The UK objective for protection of human health for Ozone is 100 µgm3. This is measured as a daily maximum of a running 8 hour mean, to be achieved by the end of 2005, with no more than 10 exceedences per year. The UK National Air Quality Strategy recognises that ozone is not easily controlled by local measures and that measures to reduce it will therefore need to be agreed at European level. The ozone objectives are therefore for guidance and are not included in UK regulations.

Minimising the effects.Prolonged still sunny weather is necessary for ozone to build up, making photochemical smog a summer phenomenon and only an intermittent problem in the UK. However, during the summer there are often regular exceedences of guidelines − particularly in the south and west. During photochemical smog episodes it is advisable to avoid taking vigorous exercise and stay indoors if possible, particularly elderly and the vulnerable. In some US and European cities photochemical smog is a more serious summer problem. Drastic measures have been taken during severe episodes, such as limiting or banning vehicle use, banning charcoal barbeques and petrol driven lawn mowers.

The problem of tropospheric ozone is not easy to solve. Tighter controls on vehicle and industrial emissions of NOx and VOCs and a reduction in traffic levels would reduce emissions of ozone precursors and ozone formation. The European Union have agreed a Directive controlling VOC emissions during petrol storage and distribution and limits on solvent emissions from industry.

What can you do?There are measures that you can take to reduce emissions of the pollutants that cause ozone formation:

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