The air quality in our homes, workplaces, and enclosed social and recreational spaces is a significant determinant of our health. This is for purely statistical reasons – estimates suggest that globally, people spend about 90% of their time indoors. In enclosed environments, we are exposed to outdoor air pollutants that penetrate indoors as well as emissions from indoor sources like cooking, cleaning, heating, and other activities and products.
Research has shown that improving indoor environments is positively correlated with better human health. Indoor air quality, or IAQ, is an important aspect of indoor environmental quality, or IEQ. Meanwhile, IEQ is an essential consideration in green building and associated certifications. Thus, enhancing indoor air quality in green buildings is a critical part of enhancing human health outcomes.
The onus of achieving high indoor air quality in green buildings and conventional buildings is not solely on homeowners or building managers. Improving every aspect of indoor environmental quality is a holistic and long-term process which ideally also involves policymakers, environmentalists, architects, and engineers. Involving all these stakeholders in the path to achieving certain baseline indoor air quality requirements is a non-negotiable if you want to take a strategic approach to sustainable living. Essentially, it is a well-rounded approach to indoor air quality in green buildings that will provide people with a pleasant experience with regard to comfort, health, and productivity.
What is green building?
Way back in the 1980s, the United Nations World Commission on Environment and Development defined sustainability. It was at this point in history that green building was conceived as a pathway towards environmental responsibility.
Green building is a way of describing sustainable building. It refers to the practice of designing and building structures using resource-efficient and environmentally responsible processes and materials. Accordingly, green buildings are those that are built using the methods and principles of sustainability to minimise their impact on human and environmental life. Think energy efficiency, occupant well-being, responsible land use, pollution control… the list goes on.
Green building goes beyond optimising just the design and construction of the building for sustainability. According to the US Environmental Protection Agency (US EPA), “Green building is the practice of creating structures and using processes that are environmentally responsible and resource-efficient throughout a building’s life-cycle from siting to design, construction, operation, maintenance, renovation and deconstruction.”
Rather than a particular technique, green building is an approach towards building design, indoor environmental quality, and occupant well-being. There are many ways of going about the process. Nonetheless, for the sake of finding common ground and outlining best practices, organisations around the world have developed green building certifications. What began in the 1990s with the BRE Environmental Assessment Method (BREEAM) certification in the United Kingdom and the Leadership in Energy and Environmental Design (LEED) certification in the United States has grown to involve many other countries.
Depending on their own environmental, economic and cultural circumstances, countries have developed their own green building schemes or applied relevant schemes from other countries. There is the Green Star system in Australia, the Comprehensive Assessment System for Built Environment Efficiency (CASBEE) in Japan, and the Deutsche Gesellschaft für nachhaltiges Bauen (DGNB) system in Germany. Additionally, although they are not directly a part of green building schemes, standards such as WELL have been designed to promote indoor air quality in green buildings as well as traditional buildings.
To comprehensively assess building sustainability, green building schemes usually have categories or rating systems. For instance, the LEED v4 scheme for building design and construction includes location and transportation, sustainable sites, water efficiency, energy and atmosphere, materials and resources, indoor environmental quality, innovation, and regional priority. The BREEAM scheme for new construction includes categories for management, health and well-being, energy, transport, water, materials, waste, land use and ecology, pollution, and innovation. Similarly, other green building schemes include other categories to assess design, construction, indoor air quality and indoor environmental quality, and other factors contributing to sustainability.
The categories comprising different green building schemes may vary, but they are all designed to assess and improve the health, energy efficiency, and environmental friendliness of buildings. Indoor environmental quality is a crucial part of this, with indoor air quality in green buildings being our priority, as it is a major determinant of human health and well-being.
Indoor air quality in green buildings: A subset of indoor environmental quality
Indoor environmental quality (IEQ) defines the conditions within a building viz. indoor air quality, visual comfort or lighting, thermal comfort, and acoustic comfort. Sometimes, ergonomic comfort is also considered a part of IEQ. Overall, IEQ comprises the environmental factors that affect the health and lives of building occupants. IEQ can be enhanced with a wide range of improvements like using natural light, ergonomic furniture, occupant control over lighting, temperature and ventilation, and acoustic design. Improving indoor environmental quality, especially indoor air quality in green buildings, can not only enhance occupant well-being but also reduce liabilities for building owners and increase the resale value of the building.
Indoor air quality (IAQ), as its name suggests, represents the presence and concentration of pollutants like particulate matter (PM), volatile organic compounds (VOCs), etc. which can have negative effects on people’s well-being. Poor IAQ can cause Sick Building Syndrome, respiratory infections, poor concentration, and other physical and cognitive effects.
Indoor air quality is an important part of indoor environmental quality, which is an important part of green building certifications. A review of indoor air quality requirements in green building certifications found that all green building schemes currently in use include IAQ. However, in the 55 schemes reviewed, IAQ made an average contribution of only about 7.5%. VOCs, formaldehyde, and carbon dioxide were the pollutants most commonly considered when assessing indoor air quality in green buildings. It is important to note that IAQ is included under different categories in different schemes. For instance, it is in the health and well-being category in BREEAM, the IEQ category in Green Star and LEED, and the socio-cultural and functional quality category in the DGNB.
The connections between energy efficiency and indoor air quality in green buildings
Resource efficiency or energy efficiency is an important part of different definitions of green building. These definitions do not explicitly mention indoor air quality. Nonetheless, IAQ is a vital part of green building, with inextricable connections (both positive and negative) with energy efficiency.
In a bid to minimise the dissipation and wastage of energy, buildings today are insulated against the outside world. With this tightening of building envelopes, however, comes the problem of indoor air quality. Ventilation, or the dilution of indoor air with outdoor air, is an important way to clean the air in enclosed environments. Buildings insulated for energy efficiency restrict ventilation, which is why to enhance indoor air quality in green buildings, they must have manual interventions like windows or other appropriate design features.
On the positive side, energy-efficient buildings which use renewable energy, green construction materials, and sustainable technologies may emit fewer harmful gases, both indoors and outdoors. If they avoid fossil fuel use, they reduce their contribution to outdoor pollution. This has a knock-on effect on indoor air quality in green buildings because the ingress of outdoor pollutants can be a major contributor to poor IAQ.
Finally, since building site is an aspect of consideration in green building schemes, many sustainable projects are located close to city centres or public transport systems to earn credits related to transport and location. However, when buildings are located in densely populated areas with busy transportation routes nearby, they are likely to be more exposed to ambient pollution, with even ventilation providing no respite. In situations such as this, energy efficiency can be conversely related to indoor air quality in green buildings.
Given IAQ’s relatively low contribution of 7.5% to green building schemes, it is possible for a building to achieve the highest level of green certification without any credits for IAQ. Given the complex interlinkages between energy efficiency and indoor air quality in green buildings, research has also pointed out that gaining credits in some aspects of green building schemes may be detrimental to IAQ.
Essentially, green building certifications may not adequately promote IAQ; sometimes, they may even undermine it. Considering these complexities and the substantial health impacts of poor IAQ, it is even more important to take a targeted approach towards enhancing indoor air quality in green buildings.
Enhancing indoor air quality in green buildings
A review of indoor air quality in green building schemes found that the schemes largely outline three methods to improve IAQ: ventilation, source control, and indoor air quality measurement.
All the certifications in the review specified ventilation as a pathway to better indoor air quality in green buildings. 77% included emission source control, with a particular focus on building material emissions. Meanwhile, 65% included indoor air measurement as a way to manage IAQ. These pathways may not be comprehensive or appropriate in all situations, but they certainly offer a framework to approach the improvement of indoor air quality in green buildings.
Ventilation.
As mentioned above, buildings today – especially green buildings designed to be energy efficient – are fairly insulated or airtight. This means that adequate fresh air is not circulated in indoor environments. This makes ventilation a necessity to improve indoor air quality in green buildings. 100% of green building certification schemes grant credits for ventilation.
Ventilation may not be an appropriate intervention in areas with very high levels of outdoor pollution or during events like wildfires or dust storms. In such situations, top-quality HVAC systems may be necessary to filter incoming air and protect building occupants’ health and well-being.
Source control.
Traditional buildings may use high levels of synthetic materials and chemicals in their construction, furnishing, and décor. Additionally, regardless of the method of construction, building occupants may use air fresheners, cleaning agents, and personal care products. Then there are also activities like smoking, cooking, etc. which people may carry out indoors. All of these products and activities release harmful gases into the air.
Emission source control is a key method to improve indoor air quality in green buildings. This can include controlling or eliminating a vast range of activities and substances – mould in damp building materials; people smoking inside the building or close to building entrances; the use of VOC-emitting paints, sealants, adhesives, furniture, and building materials; combustion in stoves, fireplaces, and HVAC equipment; radon or methane off-gassing from the soil under the building, etc.
IAQ measurement.
You cannot improve what you cannot measure. Measuring indoor air quality in green buildings can help you improve occupant health and achieve higher levels of certification. For instance, you can receive credits under 65% of green building certification schemes if you measure and target the levels of specific pollutants like VOCs, formaldehyde, and carbon dioxide. You can also gain credits under some schemes if you measure and control levels of asbestos, microbes, environmental tobacco smoke, carbon monoxide, sulphur oxides, radon, nitrogen oxides, ozone, ammonia, and particulate matter.
The way ahead: Improving indoor air quality in green buildings in the long term
We’ve said it before and we’ll say it again: the onus of improving indoor air quality in green buildings falls not only on building owners, managers and occupants but also on policymakers, builders, engineers, and architects. As such, there are gaps and improvements in building standards and design practices that can be addressed going forward.
– Air pollutants like ozone, semi-volatile organic compounds, and particulate matter have extremely negative health effects, but they are not included in all green building certifications. Remedying this can increase the standards of indoor air quality in green building certifications, ultimately enhancing occupant health.
– Green building design and construction should employ indoor air quality monitoring systems, sophisticated HVAC systems, and renewable energy sources to monitor and control IAQ.
– Natural ventilation and green roofs and walls can reduce the urban heat island effect and make architecture more eco-friendly. Additionally, using recycled but safe materials, low-VOC paints and adhesives, and sustainably sourced wood can also minimise the building’s environmental impact and improve indoor air quality in green buildings.
– Since ventilation is not always the answer, green building schemes should also grant credits for reducing pollutant exposure in different ways.
– Organisations can institute policies restricting the use of pollutant-emitting personal care products. For instance, the US Centres for Disease Control and Prevention (US CDC) prohibits the use of scented or fragranced personal care products like perfumes, colognes, and essential oils in its spaces. Since such fragrances have been associated with migraines, asthma attacks, and other adverse health effects, other organisations may also improve indoor air quality in green buildings by instituting such policies.
– While certification schemes recognise pollutant control, they are often optional elements. Developing enforceable standards for indoor air quality in green buildings could be an important step to safeguard human health.
– Mandating emissions testing of all building materials, equipment and furnishing before, during and after their use can help enforce a threshold for indoor air quality in green buildings. Continuous IAQ monitoring is an effective way of implementing such requirements as it can help with life cycle measurements and reiterate the need for recertification procedures.
For any individual, community or organisation wishing to exist sustainably, there is no way around green building. To build and maintain a truly green building, there is no way around improving indoor environmental quality, with a special focus on indoor air quality in green buildings. Indoor air quality requirements may not be enforceable today, but in our rapidly changing world – affected by climate change, increasing pollution levels, and a growing population – we must do what is right if we are to build a safe and healthy world in which future generations can thrive.
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