Urban Lighting and Its Environmental Impact

Designing urban lighting in a way that curbs its environmental impact is worthy of due care and attention, writes Tamlite Lighting’s Technical Manager Stephen Biggs.  

No one would deny that the problem of light pollution has become more acute as society has moved towards 24/7 living. The disappearance of the night sky is tied up in our ever more fast-paced world.

The quality and consistency – or lack thereof – of urban lighting has been a frequent topic of discussion for many years. Simultaneously, there has been a growing awareness of its impact in the environment.

Light pollution can take multiple forms. The IDA cites the major causes as “Glare or excessive brightness, sky glow, light trespass, stray lighting or lighting clutter.

It is not hard to envisage the scale of the problem. In the UK there are more than nine million street-lamps and 27 million offices, factories, warehouses and homes.

Moreover, the density of urban spaces is certainly increasing at a rapid rate. Data shows that in 1950 the urban population as a percent of the total population was 79%. By 1990 this had grown to 88.7%, and by 2030 it is expected to reach 92.2%.

Lighting when and where it is needed

The value of moving across to LED technologies is well-established. In some cases it can reduce energy consumption by up to 80%. The Energy Saving Trust reports if every street-lamp in the UK upgraded to LED, it would save in the region of £77million.

Poor lighting design results in energy waste. The IDA estimates that 35% of artificial light is wasted by being poorly aimed or unshielded. The nature of urban spaces may be subject to considerable variation - from busy side-streets to parks. It is vital to invoke one universal design principle when delivering urban illumination. This is that lighting should be highly directional and therefore provided only when and where it is needed.

With warmer LED fixtures added, such systems can ensure that lighting is radiated into the right space at the right time. In addition, it does it in a way that minimises light spill or trespass.

Optics are a fundamental part of luminaire performance and play a vital role in spreading light effectively and efficiently.

The correct use of optics in exterior lighting maximises the spacing in between each luminaire. As a result, it both reduces the cost of the scheme and reduces energy consumption.

Upwards Light Output Ratio (ULOR) describes the amount of upward light distributed from a luminaire. For urban lighting solutions, this ratio needs to be as small as possible, to ensure that the output angles only where it needs to be.

Lighting appropriately

Another key aspect of urban lighting design is the lack of consideration for the individual requirements of a given area. In many cases, standard fixtures can be applied across the board. It’s essential to ensure lighting is appropriate for its environment. Whether that’s a major road or pedestrianised city centre, they all need different applications. For example, a high street will typically require a far higher and more dense level of illumination than a suburban space. This is because it could fall under the remit of dark-sky preservation orders.

It is also important to maintain a high CRI (colour rendering index) where possible. This is so it can work effectively with security cameras and facial recognition software. Therefore, it's crucial for the reduction of crime in outdoor spaces. Sophisticated control systems can be scheduled to respond to the shifting lighting requirements of the daily cycle.

Expert support

All of this goes to prove that the importance of lighting design is difficult to exaggerate. In order to achieve the best lighting for outdoor spaces, more organisations are seeking to work with a specialised company. Manufacturers like Tamlite can address the key issues of urban lighting projects with an extensive range of robust solutions.

Above all, a high-quality urban lighting design will strike a balance between light and darkness. This way, there is a focus on the light without turning light sources into glare points.

The importance of proper planning when lighting urban spaces is bound to become even more crucial. This is as the number of people living in towns and cities grows. Those who want to deliver a safe, attractive, and sustainable environment must give lighting due care and attention throughout their urban spaces. This means working on the basis that lighting infrastructure can be a benefit to all citizens, and the environment, for generations to come.