Air Quality in the Built Environment

Air pollution is understood to directly and indirectly contribute to a range of social, economic and environmental impacts.

Impacts on Human Health

91% of world’s population, urban and rural, live in places with air that exceeds WHO guidelines for key pollutants [1]

• Air pollution is the largest environmental killer, with approximately 8 million deaths annually attributed to air pollution, predominantly in developing countries. 4.2 million of these deaths are a result of exposure to ambient (outdoor) air pollution, and 3.8 million are attributed to the result of household exposure to smoke from dirty cookstoves and fuels [2]. This death toll is often related to the emission of Short-Lived Climate Pollutants (SLCPs), consisting of particulate matter such as black carbon, or greenhouse gases such as methane, which are a common by-product of traditional combustion practices for heat or energy in developing nations. These SLCPs are directly linked to respiratory diseases, cancer, strokes and heart disease [3]. Over one-third of global death from heart disease is attributed to the impact of polluted air [4].
• Airborne particles of dust from construction, such as hardwood or silica dust, are also understood to cause severe health impacts including silicosis, asthma and heart disease [5]. Silica dust is often produced in the creation of concrete, so exposure to this toxic substance causes health risks across the built environment worldwide.
• In our homes, schools and work environments across the world, poor indoor air quality is understood to reduce cognitive functioning, productivity and wellbeing. The impact of airborne chemicals in the indoor environment, such as Volatile Organic Compounds, is understood to cause a range of adverse health effects, including ear, nose and throat irritation, nausea and headaches [6].
  • Focus on work environments – the business case for better air: Studies by the Harvard T.H. Chan School of Public Health have shown that workplaces with a specific focus on VOC minimisation and enhanced ventilation lead to superior cognitive functioning from the occupants than equivalent environments with higher indoor pollutants and lower fresh air intake. Cognitive scores were demonstrated in controlled trials to be 101% higher in these experiments, which reveals the potential impact on concentration, productivity and work quality polluted air could be having in a work environment [7].

Air pollution costs the global economy $5 trillion every year in welfare costs [8]

Impacts on the Environment

Widespread and fast action to reduce short-lived climate pollutant emissions has the potential to reduce the amount of warming that would occur over the next few decades by as much as 0.5°C [9].

• With close to 40% of global energy-related carbon emissions being released from buildings, this represents a substantial input to anthropogenic climate forcing from carbon dioxide. Carbon dioxide has at atmospheric lifespan of hundreds of years, meaning emissions released today will impact the climate for generations to come.
• Other greenhouse gases, including short-lived climate pollutants (SLCPs), are also being emitted from our buildings and communities and having a severe environmental impact. It is estimated that 45% of current global warming is attributed to the impact of SLCPs, such as black carbon, methane or hydroflourocarbons [9].
• Particulate matter (PM10) can create different, but equally damaging environmental impacts to greenhouse gases. Airborne course and fine particulate matter can directly alter the global balance of incoming solar radiation, distort the albedo effect and react with other pollutants [10].
• The emissions impacting the natural environment are not only from the operational phase of a building, but also include those embodied in the life cycle – both from the construction and demolition of buildings and cities. A global supply chain, including excavation, brick-making, transportation, and demolition can all be environmentally damaging, and ‘build in’ embodied emissions to a building.

Impacts on Buildings

56% of cities and towns monitoring pollution locally have levels 3.5 times or more above WHO guidelines [11]

Ironically perhaps, the air pollution that is partially created by buildings are directly impacting their ability to perform in a sustainable way.

• Where outdoor air is polluted, natural or passive ventilation strategies are often unsuitable due to ingress of polluted air and the health risks this would pose. Energy-utilising air filtration is often used as an alternative. This can further increase energy use from a building (unless generated by renewable sources or utilising highly efficient mechanical ventilation systems, such as heat recovery), which can lead to a pollution multiplier effect.
• Increased use of air-conditioning systems is understood to create local microclimatic warming impacts due to expulsion of hot air, exacerbating the urban heat island effect. This can increase the demand for indoor conditioning and the equipment noise created can further reduce the practicality of natural ventilation. Global energy demand from air conditioners is expected to triple by 2050, so the negative impact on global air quality is likely to increase [12].
• However, even inside buildings with limited exposure to toxic materials or chemicals, the risk from outdoor pollution remains present. It is believed that most of our exposure to outdoor air pollutants actually occurs when we are inside buildings, due to infiltration through windows, apertures or cracks in the building fabric [13].

Footnotes:

[1] World Health Organisation. (2018). Ambient (outdoor) air quality and health [online] Available at: https://www.who.int/news-room/fact-sheets/detail/ambient-(outdoor)-air-quality-and-health [Accessed 11 Apr. 2019]

[2] World Health Organisation. (n.d). Air pollution [online] Available at: https://www.who.int/airpollution/en/ [Accessed 11 Apr. 2019]

[3] World Health Organisation. (n.d). Reducing global health risks through mitigation of short-lived climate pollutants [online] Available at: https://www.who.int/phe/health_topics/outdoorair/climate-reducing-health-risks-faq/en/ [Accessed 11 Apr. 2019]

[4] BreatheLife. (n.d.) Health and Climate Impacts [online] Available at: http://breathelife2030.org/the-issue/health-and-climate-impacts/ [Accessed 11 Apr. 2019]

[5] Safety and Health (2015) Silicosis: what it is and how to avoid it [online] Available at: https://www.safetyandhealthmagazine.com/articles/12507-silicosis-what-it-is-and-how-to-avoid-it [Accessed 11 Apr. 2019]

[6] Environmental Protection Agency. (n.d.) Volatile Organic Compounds’ Impact on Indoor Air Quality [online] Available at: https://www.epa.gov/indoor-air-quality-iaq/volatile-organic-compounds-im… [Accessed 11 Apr. 2019]

[7] Allen, J., MacNaughton P, et al. (2016) Associations of Cognitive Function Scores with Carbon Dioxide, Ventilation, and Volatile Organic Compound Exposures in Office Workers: A Controlled Exposure Study of Green and Conventional Office Environments. Environmental Health Perspectives [Online] Available at: https://ehp.niehs.nih.gov/doi/10.1289/ehp.1510037 [Accessed 11 Apr. 2019]

[8] World Environment Day (2019). China to host World Environment Day 2019 on air pollution [online] Available at: http://www.worldenvironmentday.global/2018/hi/node/2700 [Accessed 11 Apr. 2019]

[9] Climate and Clean Air Coalition. (n.d.) Short-Lived Climate Pollutants [online] Available at: http://ccacoalition.org/en/content/short-lived-climate-pollutants [Accessed 11. Apr. 2019]

[10] Mukherjee, Arideep & Agrawal, Madhoolika. (2017). World air particulate matter: sources, distribution and health effects. Environmental Chemistry Letters. [online] Available at: https://www.researchgate.net/publication/313920249_World_air_particulate… [Accessed 11. Apr. 2019]

[11] BreatheLife. (n.d.) Who it affects [online] Available at: http://breathelife2030.org/the-issue/who-it-affects/ [Accessed 11 Apr. 2019]

[12] International Energy Agency. (2018) The Future of Cooling. Opportunities for energy-efficient air conditioning [online] Available at: http://www.oecd.org/about/publishing/TheFutureofCooling2018Corrigendumpa… [Accessed 11 Apr. 2019]

[13] Harvard T.H. Chan School of Public Health. (2017) The 9 Foundations of a Healthy Building [online] Available at: https://forhealth.org/9_Foundations_of_a_Healthy_Building.February_2017.pdf [Accessed 11 Apr. 2019]

In order to develop awareness around sustainable strategies to reduce air pollution, we present a range of solutions both by cause and by most relevant audience.

Reducing Air Pollution by Cause

Outdoor

• Emissions from buildings in-use: Reduce operational carbon emissions by targeting net zero carbon building performance, requiring optimal energy efficiency for building fabric and systems as well as sourcing of energy from renewables.
• Emissions from building life-cycle: Embodied emissions should also be considered. Local sourcing, reuse or recycling of materials all lower the pollution created by construction, transportation and demolition processes.
  • Focus on brick production: Cleaning up traditional brick production can offer impactful reductions to airborne emissions. Switching to more efficient technologies, mainly during brick firing, can reduce pollutant emissions by more than 90% according to recent research [1].
• SLCPs: The emission of Short-Lived Climate Pollutants from heating, lighting and cooking in developing countries can be substantially reduced with the widespread roll-out of clean appliances to the 3 billion people using these technologies worldwide. The replacement of traditional cookstoves, heatstoves or open fires for clean, energy efficient solutions for heating, lighting and cooking would offer a substantial reduction in global emissions and health impacts. Additionally, improvements in building quality would improve thermal comfort and reduce demand for heating. Buildings designed for their climate, using electric heat, light and power – generated by renewable means onsite or from a clean grid – is the optimum solution for reducing localised and large-scale air pollution. However, with 1.3 billion people globally facing a lack of electricity and basic fuel poverty, many living in rural or impoverished areas, the onus must be on government to roll out decentralised energy networks powered by renewables, such as low-cost solar powered photovoltaic panels.
• Hydroflourocarbons: With 1.1 billion people worldwide facing health risks due to lack of access to cooling within their buildings for basic health needs, there is a major importance of promoting sustainable, accessible cooling practices and appliances.
  • Passive design strategies, including energy efficient building fabric, vegetation and ventilation, can reduce cooling requirement within buildings and maintain comfortable living conditions.
  • Future demand for refrigeration for food and medicine as well as internal conditioning ensures demand for cooling equipment will certainly grow, with 2.3 billion people expected to purchase cooling equipment in the near future [2]. Climate-friendly cooling agents, including carbon dioxide, can be used in low-GWP (Global Warming Potential) refrigeration or cooling systems to avoid the release of HFCs. Demonstration projects led by the Climate and Clean Air Coalition are showing the economic and practical feasibility of this across the world [3]. Many developed countries have committed to an HFC phase-down under the Kigali Amendment of the Montreal Protocol and therefore should be implementing low-GWP cooling strategies from 2019 onwards.
• Construction dust: Dust production should be appropriately managed with national and organisational regulation, best practice and policy adherence on site, and other dust-reduction strategies. Off-site, modular construction practices can be preferable due to lower volume and more controlled dust production.

Indoor

• Pollutant infiltration: As we spend an average of 90% of our time inside buildings, it is understandable that the majority of our exposure to outdoor pollutants occurs inside. In our current situation, where 91% of us live in polluted outdoor environments, a conscientious approach ventilation strategy is advised [4].
  • Focus on building fabric: A better building fabric is an efficient way to reduce exposure to pollutant infiltration as well as create a more comfortable indoor environment with lower energy expenditure. Well-insulated walls can work for all climates – trapping heat can keep an indoor environment cool or warm – as well as reducing other wellbeing threats such as acoustic discomfort.
  • Furthermore, actions as individuals towards minimising our individual contribution to outdoor pollution is a recommended approach to optimising the outdoor air quality than infiltrates within our buildings.
• Ventilation: Good ventilation levels, with appropriate filtration where required, are an invaluable strategy for clearing indoor pollutants by bringing in clean and fresh air, which can help prevent or lessen negative health impacts. Optimum ventilation rates and strategies vary by climate and quality of outdoor air, however in areas with high concentrations of air-borne particulate matter, additional air filtration is often required to maintain a healthy indoor environment. Energy-efficient filtration appliances are highly recommended to reduce emissions and operating costs for the end-user.
• Mould: Mouldy walls can be caused in cold or temperate climates due to infiltration of cold outdoor air through cracks in the fabric of a building, often symptomatic of a poor building envelope, which condenses and forms damp upon exposure to warmer interior materials. The reverse is also a challenge in warmer climates, and particularly tropical countries due to high humidity and temperature contrast of cooler indoors and warmer outdoors.
  • In colder countries, improving building airtightness and quality of insulation can reduce the risk of mould build up and consequential health risks, as well as increasing energy efficiency and thermal comfort of the indoor environment.
  • In warmer climates, a focus on ventilation to remove stale air and clear condensation is vital and can be enhanced with air conditioning or dehumidifying appliances. If these technologies are highly-efficient appliances, powered by renewable energy sources, then we reduce the risk of enhancing air pollution from energy production upstream.
• VOCs: Volatile Organic Compounds are released from a range of common products, including aerosols, solvent-based cleaning products, paints, varnishes and preservatives. As awareness is raising on the health impacts of VOC exposure, low-VOC or VOC-capturing products are becoming easier to source for citizens, design professionals and the construction industry.
• Toxic materials: Exposure to toxic materials such as asbestos are banned by national and local building codes in many parts of the world. In nations where this is not the case, policy updates, training for architects and designers and awareness campaigns for citizens are valuable strategies for limiting health risks.

Stakeholder Roles in Reducing Air Pollution

Citizen

• Choose clean energy for power and transportation, and improve energy efficiency as far as possible
• Improve home building quality and avoid unhealthy chemicals in furnishings – choose low-VOC options where possible for items such as paints or carpets
• Ensure good ventilation strategy for fresh air access
• Consider investing in an indoor air quality monitor
• Engage your facilities management team and/or landlord to provide better air quality for tenants and occupiers

Business

• Choose clean energy for power and transportation, and improve energy efficiency as far as possible
• Maintain good IAQ with healthy materials and ventilation strategy and use realtime indoor air quality monitoring
• Prioritise responsible sourcing for buildings – prioritise local, ethical and recycled materials with no (or low) VOC concentrations that cause fewer emissions
• Support sustainable finance initiatives for green buildings worldwide, particularly microfinancing schemes in developing nations

Government

• Invest in clean energy, decarbonisation of national grid and support decentralised renewable energy networks in rural locations
• Promote energy efficiency by raising building standards and support retrofit programmes
• Incentivise safest and most sustainable methods of construction
• Implement national standards for building ventilation and indoor air quality
• Discourage use of known toxic materials, and legislate a minimum standard for high-risk contaminants, particularly PM2.5 and VOCs commonly found in indoor spaces (e.g. formaldehyde, benzene)
• Monitor outdoor air quality and publicly disclose data, and encourage IAQ monitoring in areas of high occupancy (offices, schools, hospitals, etc)

Footnotes:

[1] Climate and Clean Air Coalition. (n.d). Bricks [online] Available at: http://www.ccacoalition.org/en/initiatives/bricks [Accessed 11. Apr. 2019].

[2] Sustainable Energy for All. (n.d.). Chilling Prospects: Providing Sustainable Cooling for All [online] Available at: https://www.seforall.org/sites/default/files/SEforALL_CoolingForAll-Report_0.pdf [Accessed 11. Apr. 2019]

[3] Climate and Clean Air Coalition. (2019) Clean cooling technology in Jordan is a first for the Middle East [online] Available at: http://www.ccacoalition.org/en/news/clean-cooling-technology-jordan-first-middle-east [Accessed 11 Apr. 2019]

[4] World Health Organisation. (2018). Ambient (outdoor) air quality and health [online] Available at: https://www.who.int/news-room/fact-sheets/detail/ambient-(outdoor)-air-quality-and-health [Accessed 11 Apr. 2019]