Seemingly healthy building materials could be adversely affecting indoor air quality – but there are some simple ways to reduce the harmful substances emitted
Within almost all new buildings and renovation projects, substances are released into the air that can have a wide range of negative impacts on our health. These include nose, eye and throat irritation, headaches and nausea in the short-term; and liver, kidney and central nervous system damage over time. Moreover, many of these substances are known or suspected carcinogens. Yet plenty of architects remain largely unaware of this issue – perhaps unsurprisingly, as it is hardly a headline topic within architecture schools or many CPDs.
These substances are known as VOCs, or volatile organic compounds, and while they may not at first glance appear as a major health problem, indoor air quality is responsible for around 4.1 per cent of all global deaths, and has been called 'the world’s largest single environmental health risk' by the World Health Organisation. Research by the United States Environmental Protection Agency found levels of about a dozen common organic pollutants to be between two and five times higher inside homes than outdoors, regardless of whether the homes were in rural or highly industrial areas.
There are many sources of indoor air pollution, including log burners, gas stoves, cleaning products and even printers – but many VOCs come from materials used in the construction of buildings.
The biggest offenders tend to be insulation, flooring, paints, adhesives, sealants, glues and coatings. Furniture too can be a significant emitter, as it often contains particle board, plywood or glues. Many of these products can release toxic gases such as formaldehyde and toluene for as little as 72 hours or for over 20 years in a process called ‘off-gassing’. This puts occupants’ health at risk if the building is not well ventilated.
It can be challenging to specify truly healthy materials. We may think, for example, that a ‘natural’ material like plywood will be good for both people and planet. However, many plywoods use formaldehydes to add structural and moisture durability. As a result, they can off-gas harmful substances like urea-formaldehyde, which can cause serious health issues, including cancer.
Help is at hand, however. There are now a wide range of products and furnishings available that are low in VOCs. The WELL Building Standard, for example, recommends a number of material accreditation schemes such as the Declare Label, Cradle-to-Cradle Certification, Product Lens Certification or Global Green Tag product health declarations, with further product recommendations and performance criteria found within BREEAM’s 'Hea 02 Indoor air quality’ credit.
Architects who are keen to design healthier buildings should aim to specify products that meet such accreditations or criteria, or contact manufacturers directly to enquire about any VOC testing that may have taken place.
For designers on a limited budget, upcycled materials or furniture can be an excellent solution for both humans and the environment. As they tend to do most of their off-gassing in the early stages of their lives, a second-hand rug, sofa or stack of OSB is likely to emit far lower levels of VOCs, as well as supporting the circular economy.
Natural ventilation is often not an ideal solution for controlling air quality as external air pollution is likely to be an issue
Specifying healthy materials is, however, only half the battle. It is rarely possible to completely eliminate indoor air pollution (humans ourselves are excellent carbon dioxide emitters, which can cause headaches, reduced cognitive performance and slower reaction times even at mid-level build-up), so good ventilation is essential.
While we’re seeing a push towards natural ventilation, this is often not an ideal way to control air quality. With increasing numbers of us living and working in urban environments, external air pollution is often likely to also be an issue, meaning we may simply be trading VOCs for nitrogen oxides or other harmful substances.
The argument that natural ventilation is better for the planet doesn’t always stack up either, particularly in the UK where opening windows often means turning up the (frequently gas-powered) heating – something that is likely to become even more problematic as a result of the current fuel-poverty crisis. In reality, the risk is that many people simply won’t open windows, leading to other problems such as condensation and mould which also have significant health consequences.
Instead, a low-energy ventilation system with heat recovery (like those seen in Passivhaus projects) is likely to be a better approach. These can be designed to include high-quality (eg HEPA) filters, which can theoretically remove at least 99.97% of dust, pollen, mould, bacteria, and any airborne particles with a size of 0.3 microns (µm). Research from Cambridge University even shows they can be effective against pathogens such as Covid-19.
Finally, there are materials and finishes emerging that, rather than off-gassing VOCs, can remove them from the air. British Gypsum, for example, now makes a range of plasters and ceiling finishes that absorb formaldehyde, turn it into inert compounds, and store it within the plaster. Similarly, paint manufacturers such as Graphenstone offer VOC-free products, some of which can absorb CO2 from the air.
Fortunately, our understanding of the ways in which building materials and products impact indoor air quality and human health is constantly improving. With this understanding comes a moral obligation to put this knowledge into practice, creating buildings that, instead of causing harm, actually help their occupants to lead healthy, happy lives.