TECHNICAL ASPECTS OF LIGHT POLLUTION
28/12/2023
Roger Mira
Light pollution is a cross-cutting problem, with multiple facets, which causes a myriad of damage that is imperceptible at first glance, but which accumulates over the long term. Its effects not only have repercussions on our health and that of other living beings, but also disrupt the movement of vehicles on public roads, causing traffic accidents by causing night-time glare due to poorly installed or poorly designed street lamps, overly bright advertising panels along roadsides or pharmacy signs that emit an excessively aggressive green light; tunnels should be more brightly lit during the day than at night to avoid glare, but this basic principle is not always taken into account.
Air traffic is not spared from the consequences: airline pilots become disoriented when they have to land at airports such as Valencia, Barcelona or Madrid, which are surrounded by major sources of light pollution, especially on days with reduced visibility.
The fight against light pollution is relatively simple, it is about lighting with common sense and, if we focus on public lighting, we have to stick to 5 basic principles:
- The street lamps used must always direct their light downwards, never sideways and certainly not upwards (there is nothing to light in the sky and the light we send upwards is energy that is lost, but paid for out of our pockets).
- In population centres, the number of streetlights should be installed as strictly necessary and no more: otherwise it is a form of wastefulness like any other.
- These lamps should use bulbs of just the right wattage, with the amount of light emitted being reduced at times when the streets are not very busy.
- Light bulbs should emit yellowish or orange light, avoiding white LEDs at all costs, because of the bluish component they emit, with the consequences for our health that we have already mentioned in other blog posts, and because blue (cold) light is more dispersed in the air than warm-coloured light.
- In the same way that we switch off the lights inside our homes when we are not using them, we should switch off the elements of outdoor lighting that are unnecessary at certain times of the night (monuments illuminated at times when they cannot be visited or illuminated signs that continue to operate at times when the streets are deserted, for example).
As we have said, light is a form of energy and, therefore, irresponsible lighting in municipalities is a double source of environmental damage: firstly, due to the effects it has on living beings because they receive light at times when they should be in complete darkness, and also because in order for light bulbs to produce light, electricity must first be generated to power the bulbs. At night, solar panels do not work and the wind tends to calm down, causing a decrease in wind production, so it is necessary to increase the performance of thermal power plants to meet the demand for electricity required to overlight populations, with the harmful effects of increasing CO2 emissions, one of the main gases causing the greenhouse effect, which is causing global warming on our planet.
The over-lighting of towns and cities also leads to the impoverishment of public administrations, as they have to pay extra for lighting that could be used for other purposes that would have a direct impact on citizens’ quality of life: improvements in social services, health, culture, education, infrastructure, etc. We have unconsciously assumed the idea that more street lighting is synonymous with more wealth, but the reality is quite the opposite: only efficient and responsible lighting ensures a balance between safety when we walk the streets, respect for the environment – and our health – and economic sustainability for the public administrations that manage night-time lighting.
