Pollution from and within the built environment is a threat to biodiversity and human wellbeing.
What’s going on?
The buildings and infrastructure sector is a substantial contributor to various forms of pollution including water, air, noise and light pollution.
Pollutants can be emitted throughout the lifecycle of a built asset or project – from construction, materials transportation, use of heavy vehicles and site works, through to use and then final demolition. Engine powered tools and diesel generators, for example, release GHGs, nitrogen oxides (NOx), ozone, fine particulate matter and dust.
In the UK, construction activities are one of several primary sources of dust particles including PM10 and PM2.5 [source]. The heating and cooling of buildings, meanwhile, can create air pollution. Nitrogen pollution in the form of nitrogen oxides alters the availability of nitrogen, which can disrupt food-web structures, enable invasive or non-native species and harm primary producers as excessive levels of nitrogen damage the cellular machinery required for photosynthesis.
An estimated 28,000 and 36,000 deaths a year can be attributed to long-term exposure to air pollution in the U.K., which disproportionally affects deprived urban areas [source].
Nitrogen pollution in the form of nitrogen oxides can also be very harmful to the environment. Nitrogen availability limits the primary productivity of many ecosystems and therefore impacts trophic dynamics and species distributions. Nitrogen pollution alters the availability of nitrogen which can disrupt food-web structures, enable invasive or non-native species and harm primary producers as excessive levels of nitrogen damage the cellular machinery required for photosynthesis.
All these impacts result in a loss of biodiversity and more specialised species. Nitrogen pollution also contributes to acidification and eutrophication of sensitive habitats and can reduce terrestrial carbon storage [source]. Easily transported by wind, air pollution also impacts natural areas far removed from the original source of emissions. Impacts can be so severe that in parts of the U.K., such as the Solent, property development cannot take place unless it demonstrates ‘nutrient neutrality’ [source].
The nitrogen cycle is a key earth system process and current levels of nitrogen pollution are far more than what can be considered safe limits. Building and infrastructure designers can help to limit nitrogen pollution by designing built assets that limit the need for the combustion of fossil fuels – installing renewable energy technologies (i.e., solar panels or micro-wind turbines) or facilitating sustainable transport.
The construction and use of buildings can also result in a wide range of water pollution effects. During construction, chemical contaminants (such as glues, paints, concrete wash or varnishes), heavy metals and hydrocarbons from fuel can mix or become dissolved in water. These pollutants can easily be transported off-site and enter nearby watercourses, ponds, lakes and groundwater or seep into soils.
Groundworks and the use of heavy machinery can cause large amounts of soil erosion which can create silt laden waters – increasing the turbidity of water, which can have devastating effects on aquatic life. Effluent discharge is another increasing problematic issue, with 400,000 incidents occurring in 2020 alone [source].
Construction also creates noise and light pollution within the urban environment which can negatively affect wildlife including both plants and animals and cascade through an ecosystem in complex ways [source]. In addition, direct and indirect human disturbances associated with construction and infrastructure disrupts species lifecycles, feeding, breeding and nesting often resulting in declines species abundance. Whilst we want to connect people to nature, we also need a balance of protecting wildlife from human and associated pet disturbance in some contexts.
Plastic pollution – especially microplastics – are also a major concern. Because plastic does not biodegrade and can persist for centuries, microplastics (defined as fragments of plastic less than 5mm in length) can very easily accumulate within the environment. And, microplastics are thought to now be present in every part of the environment, and have been found on mountain tops, rivers, lakes and across the marine environment including at the bottom of the Mariana Trench [source]. The most concerning aspect of microplastic pollution is that they can be easily ingested and accumulate in bodily tissues.
The construction industry significantly contributes to plastic pollution and is the second largest consumer of plastic in the UK after the packaging industry. However, designers can help reduce the impacts of plastic pollution, by reducing avoidable plastic materials in their products, reusing existing plastic materials from waste or recycling plastic products at end of life, ensuring we effectively capture and manage plastic waste.
Getting nature positive
While the built environment can cause significant pollution issues with negative consequences for public health and biodiversity, conscientious project planning, building and infrastructure design can help markedly ameliorate the impacts of pollution.
This includes using sustainable drainage systems (SuDS) to limit water pollution, appropriately designing lighting using natural waste and storm water treatment and designing out air pollution.
Inspired by steps buildings and infrastructure companies are already taking, we’ve compiled suggested actions to help you on your journey to getting nature positive