MONDAY 14 JULY 2003

MR D COATHAM, MS G CLARKE, MR N SINDEN AND MR T OLIVER

  Chairman: May I welcome you to our session on light pollution and thank you very much for taking the time to come to give evidence. The impolite bit now is that we are due to vote in a minute, but there will be no problem after that. Apologies for keeping you waiting but we had some other reports to see through. May we start by asking Geraldine to fire the first one?

  Q86  Geraldine Smith: What type of street lighting should we be installing in urban areas and in rural areas?

  Mr Coatham: There is a predominance in this country of low pressure sodium lighting at the moment which is the bright orange single coloured light. That light was put up a lot in the 1970s because it was energy efficient at that time. However, it is very difficult to control the light from it because of its sheer physical size. There are more modern lanterns on the market now which use high pressure sodium lamps, which can be very much more controlled and they can direct light downwards whilst still spreading it along the length of the road, so we can maximise the spacing of lanterns to give us an economic light source. That was one way of dealing with it. There are also new light sources coming on which give out white light. In small areas such as housing estates, where we are using low lighting levels, there is a potential to reduce lighting levels because the white light allows you to see as well as you would do under a high Pressure Sodium light source.

  Q87  Geraldine Smith: You were telling us about the street lighting we should be installing.

  Mr Coatham: As an institution we would therefore recommend that all lanterns be designed so that there is no upward light from them, that all light goes downwards. However, we do have some concerns over a strict requirement to put full cut-off lighting on everything, because experiments are being carried out in Europe at the moment which would indicate that you can reduce the overall amount of light pollution by having slightly shallow dish bowls, which allow you to get the maximum spread of light without the major cut-off. There are areas, like the sites of special scientific interest and areas round major astronomical laboratories, where we would agree that full cut-off should be put in. There are arguments not to do it everywhere.

  Q88  Geraldine Smith: Is the lighting you are recommending more expensive than existing lighting?

  Mr Coatham: No; no. There is quite a number of the slightly shallow luminaires on the market nowadays and most of the good manufacturers produce one; they are readily available and there is very little, if any, difference in cost, certainly no difference in running cost and maintenance cost thereafter.

  Q89  Geraldine Smith: Are there certain types of street lighting which you think the government should prohibit local authorities from installing?

  Mr Coatham: I certainly would like to see some control over standard low pressure sodium lights now. They have had their day; they should be gradually taken out of service as and when they fail and be replaced with better designed luminaires. I cannot see the point in putting them in nowadays. High pressure sodium lighting can be installed as cheaply, if not more cheaply and run in the same way as that nowadays. We would recommend that low pressure sodium be taken out of use. Apart from street lighting we would also like to see some control over domestic security lights. We receive lots of complaints from neighbours about domestic security lights which have been put up very badly. People do not understand the problems with these lights and unfortunately just put them up and use far too much light for what they need. We are endeavouring to talk to some of the big DIY chains to try to get this over. I have a meeting with one of them in early September and they are looking at taking one of our documents and amending it to suit their requirements and then putting it as a free handout in their stores, which we hope will influence people.

  Q90  Geraldine Smith: What would you say is the percentage of low pressure sodium lighting in the UK?

  Mr Coatham: I did try to work this out very quickly and from the latest figures we have, which actually only cover England, something like 45% of the street lighting is of that type. That is just for England. I do not see any reason why that figure should alter greatly across Northern Ireland, Wales and Scotland.

  Q91  Dr Iddon: Why have local authorities got to the position they have got to when we have had an Institution of Lighting Engineers? Why have they not been properly advised in the past?

  Mr Coatham: I would say that they have been advised in the past. There are some forward thinking people out there. Unfortunately street lighting equipment has a life expectancy of anything up to 25 or 30 years when it is designed and a lot of the installations which were put in in the 1970s are still there because of that. They are coming to the end of their life. We are hoping that when people start replacing them, they will replace them with better controlled lighting.

  Q92  Chairman: With the modernisation of our country, who are the biggest culprits these days? Sports facilities, or what? What would you pinpoint as the worst?

  Mr Coatham: Street lighting engineers are starting to understand the problems. A little more education is still needed there to get them to understand it a bit more and I would like to see local authorities made to write street lighting policy documents, which are published for the public to see and discuss. Going beyond that, there is a lot of concern with things like the out of town shopping centres. There is a major one on the outskirts of Manchester where the motorway running alongside of it has a beautiful system of full cut-off lighting, well controlled and everything else, and the big shopping centre probably has more lights on it than the motorway has. It is just any old light and it is throwing light all over. There does not seem to have been any control on that.

  Q93  Chairman: Is there an objective quantitative method by which you can measure the light which goes up above the horizontal and that which goes down?

  Mr Coatham: It is very difficult to measure that. However, in the planning stage, there are methods by which, when you are designing the lighting, you could actually calculate what should happen with the designs you have by taking what is falling onto the ground. With a lot of the calculation packages now, you can calculate what is happening a metre or two metres above the lighting columns.

  Q94  Chairman: But not many people do that, is what you are saying.

  Mr Coatham: I doubt anybody does it at the moment.

  Q95  Dr Turner: The problems with measuring light pollution is one of the reasons cited by the government for not taking any action on light pollution so far. Clearly I can see that there are technical difficulties in assessing the light pollution of a whole town, for instance. Do you think that there are alternative approaches which planning authorities could take, like only permitting the installation of light fittings of an approved design, that is full cut-off or as near as possible, which would control the problem directly?

  Mr Coatham: That is one way of dealing with the problem. An alternative one is to require them, when they are submitting designs for planning approval, to carry out an impact assessment on the lighting and that impact assessment should include what the amount of light going upwards is. I believe you can calculate that using modern programmes. They should also be required to do an impact assessment of the light falling onto properties around. We get a lot of complaints from people who suddenly have a sports centre, or what has been a black playing field up to now has some floodlights erected because grants have been made available through the various commissions and that. You get these going up and because it is cheaper to buy a cheaper floodlight than one of the better floodlights, which control the light, there is a tendency quite often for the cheaper floodlights to go in. They not only throw more light upwards, but they tend to throw it further away from the area being lit and therefore throw light onto people's properties. It is difficult to measure light going into the sky, but you can do that by a pre-calculation. By pre-calculation, you can also estimate what light will fall on properties. That can be measured afterwards. It is quite simple to take a light meter out and stand at a window of an inhabited property with a light meter and measure what light is falling onto that window and therefore what light is going in to that property.

  Q96  Dr Turner: Would you favour a lighting impact assessment being a standard part of every planning application?

  Mr Coatham: I certainly think, where exterior lighting is involved, it would be a major step forward, because it would make the developers think more about what they were doing and it would require planning authorities to consider light as a nuisance more and think about it before they granted permission for people to go ahead and put in a floodlight.

  Q97  Dr Turner: If we were to take effective measures to control light pollution, how long do you think it would take before we actually saw any significant diminution, because obviously you cannot immediately take out all the lighting which has been put there? How long do you think the replacement would take to bring us down to a much lower level?

  Mr Coatham: Street lighting has an economic design life of 25 to 30 years, so people putting in street lighting now would not really expect to be having to take that out for another 25 to 30 years. I would suspect that on a lot of the floodlighting installations we are talking about for sports, it would have a similar life expectancy. However, the major developments like Old Trafford and that type of flood lighting, have a much shorter turnround because they need to do it to keep up with CCTV requirements. They usually do take account of floodlighting problems and light pollution.

  Q98  Dr Turner: Would you agree with the crude estimate that we are directing about one gigawatt of energy into lighting up the sky at the moment and not even lighting the ground with it? There was a major opportunity for energy efficiency savings there.

  Mr Coatham: I have read the report from the last session you had and saw that figure there. I suspect the figure does not seem too out of keeping. I would query how the calculation has been done, because I agree fully with anything that is going above the horizontal is lost light. If I remember right, it said that anything down to 15 degrees below the horizontal should also be classed as lost light, because it does not reach anywhere. To an extent, that is correct. However, to maximise the spacing on street lighting, there is a need to maximise the angle at which you let out the light. More and more modern luminaires are pushing the angle as far as they can and trying to cut the run-back on them as much as possible. We just have to be careful that we do not land up putting a cone of light down which will mean that we have to put the lighting columns closer and make the schemes more expensive.

  Q99  Dr Iddon: We have seen the nice pictures taken from satellites which dramatically show light pollution on earth. Have you taken any measurements from the ground, or do you know anyone else who has taken measurements from the ground, of light pollution at the terrestrial level?

  Mr Sinden: The CPRE has not, but what the map shows is a very clear trend of increasing levels of light pollution between 1993, the baseline date which we used, and 2000. It is important in terms of the debate we were just having about measuring light pollution, that whilst there may be some interpretation problems in the way in which the figures we have generated have been produced, nevertheless a very rigorous methodology was applied to the process. You will have read the report about the data being based on satellite images received by US Air Force satellites. Effectively what that is measuring is the amount of light beaming upwards from the ground and affecting the night sky. It goes down to a level of detail of the light emitted around about 100 homes being picked up by the satellite. It would not pick up individual lights or a smaller scale than that. The data we have published show that the area of truly dark skies has declined by 27% during those seven years and the area experiencing the most severe light pollution has increased by 17%. When it comes to your question about measurement on the ground, I am very interested to hear what ILE say about how easy that can be. This is very important, in the context of the countryside quality and countryside character aspect of light pollution, which we are obviously very interested in as an organisation, perhaps more so than the impact on astronomy. It is important to recognise that the government have a commitment to tackle the issue of declining countryside quality and countryside character. The Rural White Paper has a commitment to publish a Countryside Quality Indicator next year, which we hope will embrace the issue of light pollution. In that connection we are very keen to pursue discussions with both Defra and the Countryside Agency about the need to ground truth the data we published in our maps, so that we can take account of local topographical situations, local landscape features and the impact of individual but scattered lighting on the character of a landscape. That is as important to us in terms of countryside quality as is the importance of the dark sky at night itself. CPRE has not done any ground truthing, but we are very keen to encourage Defra and the Countryside Agency to do so in the context of their work on countryside quality.