WorldGBC network celebrates UN’s International Day of Clean Air for Blue Skies
A thought leadership piece by Catriona Brady, Head of Better Places for People, WorldGBC
In recognition of the United Nation’s first international day of Clean Air for Blue Skies, the World Green Building Council (WorldGBC) is proud to contribute the following thought leadership article, highlighting the pivotal role the built environment sector must play in tackling the global air pollution crisis and presenting a call to action for our global network and the wider industry. WorldGBC is proud to be a member of the Climate and Clean Air Coalition.
Air pollution is the greatest environmental threat to human health
Air pollution is considered the greatest environmental threat to human health, causing approximately seven million deaths each year[i] due to heightened mortality risk from stroke, heart disease, pulmonary disease, lung cancer and respiratory infections[ii]. Polluted air is the consequence of the excessive release of greenhouse gases, short-lived climate pollutants, toxic chemicals, biological contaminants and many other sources. The better-known air pollutants are also causing unmitigated damage to the environment as potent drivers of climate change.
With 9 out of 10 people worldwide breathing polluted air and exposed to pollutant levels above World Health Organization guidelines, this is a global health and environmental emergencyii. The WorldGBC network recognises air pollution as a sustainability crisis directly related to the built environment and runs a thought leadership campaign around Air Quality in the Built Environment as part of our Better Places for People global project.
Read on to find out why buildings and cities are causing and impacted by air pollution, and what can we do about it.
What is the role of our built environment?
Our buildings and cities expose us to both indoor air pollution and ambient (outdoor) pollution. Ambient pollutant sources are multi-faceted and geographically varied, and include transport, waste and energy generation. Cities form the community infrastructure where we are exposed to emissions from various sources, such as transport, but it is important to recognise that our buildings are major emitters themselves. Both indoor and outdoor air pollution sources have distinct causes from all stages of the building lifecycle and must be tackled accordingly to protect human health and wellbeing.
How are buildings causing air pollution?
Buildings generate a huge quantity of pollution across their lifecycle, with 39% of global energy-related carbon emissions attributed to buildings[iii]. 28% of this is buildings in operation, predominantly for heating, cooling and lightingiii. Energy use is heavily impacted by the quality of the building envelope, with emissions especially high in older building stock.
In addition to carbon emissions, operational buildings release a host of other toxic pollutants, including fine particulate matter (PM2.5). This is caused by fuel combustion to heat and power buildings (particularly in developing nations where solid fuels are a primary power source), and hydroflourocarbons (HFCs) — cooling agents in air-conditioning and refrigeration systems.
The traditional building construction process is highly polluting. 11% of the 39% of global carbon emissions from buildings is ‘embodied’ in the construction process, which has a well-catalogued impact on the environment from waste generation, water use, dust creation and greenhouse gas emissionsiii. In particular, manufacturing and heavy industry (steel, cement and iron) and the creation of building materials are major emitters. Brick kilns contribute to up to 20% of global black carbon emissions, alongside steel and iron production[iv].
On a local scale, building construction can be responsible for the release of toxic dusts such as silica or hardwood, which are carcinogenic. This is particularly damaging to the health and wellbeing of construction workers, and people living in close proximity to uncontrolled construction sites.
Once indoors, the situation becomes complex. Indoor air pollution can be created from fuel combustion (solid fuels create PM2.5 pollution, and natural gas leads to nitrogen dioxide emissions from unvented gas-based appliances), biological contaminants such as airborne mould spores, and exposure to chemicals such as Volatile Organic Compounds (VOCs) found within household fabrics, furnishings and possessions. Additionally, user behaviour can alter indoor environmental quality, with inadequate ventilation and occupier activities as two further sources of poor indoor air quality (IAQ).
The situation between in and outdoor pollution is made more complex by the relationship between the two. It is estimated that 65% of our exposure to outdoor air pollution occurs indoors due to the expanse of time spent within buildings[v]. [HJ1] Furthermore, the emissions multiplier effect is a high-risk scenario in urban areas. Urban ambient air quality is generally poor and mechanical ventilation is often utilised to protect building occupants from incoming pollution. This increases energy use, creating further emissions and pollution upstream, and can contribute to localised environmental issues such as the urban Heat Island effect.
What are the solutions?
In recognition of the strive for Clean Air for Blue Skies, we focus on solutions tackling ambient air pollution. For more information about indoor air quality and solutions, read here.
The impact of the built environment on the air pollution crisis is created at all scales. It is impacted by urban planning, building occupier behaviours and socio-economic factors, local and national building and construction policy and energy codes, and local construction practices.
Wider emissions sources must be tackled in a bespoke, but internationally connected manner. Short-lived climate pollutants from the use of traditional fuel sources from heating, lighting and cooking in developing countries require the widespread roll-out of clean appliances to the 3 billion people using these technologies worldwide. The use of fossil fuels worldwide must also be phased out, with energy-efficient renovations encouraged to transition from gas power to electrification to reduce NOx emissions in the home.
What can I do?
For more information about how you can get involved in WorldGBC’s Air Quality in the Built Environment campaign, please contact Catriona Brady, Head of Better Places for People, email@example.com
With thanks to our partners:
[i] UNECE Air Pollution and Health https://www.unece.org/environmental-policy/conventions/envlrtapwelcome/cross-sectoral-linkages/air-pollution-and-health.html#:~:text=Air%20pollution%20is%20now%20considered,pulmonary%20illnesses%20and%20heart%20disease.
[ii] World Health Organization. Health Topics: Air Pollution. https://www.who.int/health-topics/air-pollution#tab=tab_1
[iii] International Energy Agency. (n.d.). Energy Efficiency: Buildings. [online] Available at: https://www.iea.org/topics/energyefficiency/buildings/
[v] Fisk WJ, Chan WR. Effectiveness and cost of reducing particle-related mortality with particle filtration. Indoor Air. 2017;27(5):909-920
3 Science Direct: Chemical exposures in recently renovated low-income housing: Influence of building materials and occupant activities https://www.sciencedirect.com/science/article/pii/S0160412017308413