Leeds Astronomical Society LAS Meetings Observing Membership



Things you can do

By and large light pollution isn't seen yet as a mainstream environmental problem. Occasionally, newspapers and TV media will feature 'Insect Apocalypse' stories based on recent research papers, or news of 'Dark Sky' parks, but environmental campaign groups like Greenpeace and Friends of the Earth haven't really caught on yet to the issue. It's not all doom & gloom however, organisations like CPRE and Buglife do help to raise awareness & the National Trust also acknowledges the impact of light pollution in their 2019 State of Nature Report, calling it "one of the most pervasive – and yet under-recognised – causes of environmental pollution".

The Government too have made some encouraging noises, with DEFRA's 2018/9 '25 Year Environment Plan' stating "We must ensure that noise and light pollution are managed effectively"[1] and their 2019 'Landscape Review' recommending "A night under the stars in a national landscape for every child".[2]

There are of course things you can do yourself, to minimise light pollution from your home:-

And by becoming more proactive, if you want to do more...


Security & Other Exterior Lights

What is the most effective angle to position security lights?

Move your mouse to change the angle of the Security Light.

(Images adapted from the CfDS.)

Although Security Lighting are often sold as "ideal for deterring intruders" and may buy peace of mind, consider that only 55% of domestic burglaries in England & Wales take place in the dark, whilst 45% occur in the daytime.[3] This indicates that the presence of external light isn't a strong deterrent. Also, it has been reported that 48% of burglaries take place in homes with exterior lighting,[4] which again suggests that Security Lights offer little if any protection against the would-be burglar.

There is however evidence that internal lights, left on in the hall for instance, can act as a deterrent as burglars are less likely to break in to a house that looks occupied.

As you can see from the above CfDS interactive demo, when fitting a Security light, it is important to ensure it points towards the ground. This not only better illuminates the area needed, but also minimises glare and cuts down on wasted light that just otherwise would shine up into space.

Today, practically all Security lights on offer from UK DIY chains are LED's with a 4,000K or 5,000K CCT (Colour Correlated Temperature). These create a 'cold' blueish harsh white light. Neither spectral temperature is ideal from a light pollution perspective, where generally the lower the CCT the better. Ideally lights should have a CCT of 3,000K or less, with a 'warmer' softer light.

When fitting a security light, ensure that it can be positioned to only illuminate the area required, and isn't too bright. Be aware that many of the designs avalable only offer limited vertical adjustment. The light should be positioned so that it doesn't shine on neighbouring gardens or property, and ideally the light output should be below 500 lumens.

Also ensure that the light is controlled by a PIR detector, and that it too can be adjusted so that it it only triggered when you want it. i.e. it shouldn't be triggered by passers by on the street, or neighbours in their own gardens! Some lights sold online, also include built in security cameras, which may also be something else to consider.

Other Exterior Lighting...

For other forms of exterior lighting the IDA have published a 5 point guide, reproduced below, which covers best practice.

First and foremost, consider whether the lighting is needed, particularly in gardens. In the urban areas of Leeds, our gardens are home to 75% of the insects in the city[5] and they are significantly affected by artificial light at night. Decorative LED lighting, such as rope lights in trees and bushes should be avoided.

All lighting should follow the 5 principals listed below:-



It might seem a bit silly, but closing curtains at night really does help cut down light pollution. It also helps to save money & carbon, no to mention cutting down chilly drafts around the windows.

The amount of heat lost through windows depends on the type of property (i.e. detached / semi-detached / terrace etc), it's age, and how well it has been insulated. For a typical house in Leeds, about ≈10% of the heat is lost through the windows. Drawing your curtains at night will cut that by about half and save you about ≈£28 a year.

Thicker curtains with thermal lining are best...


Nuisance Lighting

The local council is responsible for looking into complaints about artificial light, but only if the light is classed as a 'statutory nuisance' as covered by the 1990 Environmental Protection Act.[6] For a light to be considered a statutory nuisance it must either 'unreasonably an substantially interfere with the use or enjoyment of a home or premises' or 'injure health or be likely to injure health'.

The Act only covers lighting which is not maintained or used properly from:-

  • Security Lights (Domestic and commercial)
  • Sports facilities (like floodlit football pitches)
  • Decorative lighting of buildings or landscapes
  • Laser shows and light art

A number of artificial lighting sources are exempted from the Act:-

  • Airports
  • Harbours
  • Railway premises
  • Tramway premises
  • Bus stations
  • Public transport operating centres
  • Goods vehicle operating centres
  • Lighthouses
  • Prisons
  • Defence premises like army bases
  • Premises occupied by visiting armed forces
  • Street lights

Furthermore, there is no set level of illumination for it to be considered to be a statutory nuisance.

For more details see:- www.gov.uk/guidance/artificial-light-nuisances-how-councils-deal-with-complaints

In Leeds complaints about lighting account for ≈4% of the Environmental Heath complaints to the council.[7] Between 1st Jan 2017 and 31st Jan 2021, there were just 376 lighting complaints - less than 2 a week.

To register a complaint you can use an online form on the Leeds City Council website, but don't be surprised if it just mentions air quality, dust, smoke or odour & doesn't list light pollution!


Star Counts & Campaign Groups

We've included Campaign Groups on a separate page, but it's worth mentioning that CPRE which holds an annual 'Star Count'. Whilst the accuracy of this may be dubious, given the variability of people's eyesight & the small sample size, it nonetheless does help raise awareness of light pollution & often gathers significant coverage in the press.


Contacting the Local Council

If a street light outside your home is disturbing your sleep, the Council's contractor will probably be able to fit a baffle to help prevent light spill. To contact them, or to report a faulty street light use the two online forms here.

Other problems with Nuisance Lighting is dealt with by the Council's Environmental Health team.

Should you wish to raise the problem of light pollution with your local councillors, their contact details can be found here.

The Council is currently replacing 86,000 street lights in Leeds with LED lamps. The program has so far fitted over 25,000 lights and is due to be completed by Oct. 2023.


Contacting your MP

In parliament, the APPG (All Party Parliamentary Group) for 'Dark Skies' advocates for dark sky issues to be included within Government policy. You can ask your MP to support their efforts, and to make him/her aware of the issues surrounding light pollution via email. (For more on the APPG see their website).

You can find your MP's contact details using this online resource. Remember to include your name & address, so that they know you're one of their constituents, and to follow these guidelines. It is also worth letting them know whether you need a reply.

Leeds has six MP's. Alex Sobel, the MP for Leeds North West has indicated support for tackling light pollution as part of the response to the biodiversity crisis & climate change. Hilary Benn has also previously spoken against the use of part-night switching of street lights.[8]

One of the proposals in DEFRA's "Landscape Review" in Sept. 2019 is for "A night under the stars in a national landscape for every child".

[1] DEFRA – "A Green Future – Our 25 Year Plan To Improve The Environment" (2018/9) https://www.gov.uk/government/publications/25-year-environment-plan
[2] DEFRA - "Landscapes Review" (2019) https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/833726/landscapes-review-final-report.pdf
[3] Office for National Statistics "Nature of Crime: Burglarly" April 2009 - March 2020 average. https://www.ons.gov.uk/peoplepopulationandcommunity/crimeandjustice/datasets/natureofcrimeburglary
[4] Austrian Government – "Austrian Guidelines For Outdoor Lighting" (2019) https://www.land-oberoesterreich.gv.at/files/publikationen/us_Leitfaden_Guidelines_Outdoor_lighting_english.pdf
[5] University of Bristol - Urban Pollinators Project "A systems approach reveals urban pollinator hotspots and conservation opportunities" Lay Summary paper is publically available. Full report is behind a paywall. http://www.bristol.ac.uk/biology/research/ecological/community/pollinators/news/2018/nee-lay-summary.html
[6] https://www.legislation.gov.uk/ukpga/1990/43/part/III/crossheading/statutory-nuisances-england-and-wales
[7] https://datamillnorth.org/dataset/service-requests
[8] https://www.bbc.co.uk/news/uk-politics-30569215





Image Source: US Dept of Energy / Acuity

CCT - Correllated Colour Temperature is often used to describe how 'white' a light appears to the human eye. The figure in Kelvin (K) relates to the emission spectrum of a perfect black-body when heated to that temperature. For example, when first heating a tungsten filament it emits a dull-red light & as it heats up will glow orange/yellow & at higher temperatures will become ‘white’ hot. This is why higher Kelvin CCT lights appear to have a blue-white light appearance and lower Kelvin lights a softer yellow hue.

CCT is quite a crude measure of the actual spectrum of light, but in general it is best practice to use lamps with a CCT 3000K or preferably less.

Paradoxically we perceive the lower CCT lights as 'warmer' and the higher CCT lights as 'colder'...