The hidden hazard of indoor pollutants

Associates Workshop: Health

Historically, many conversations around air quality have centred on external traffic pollutants, but recently a shift has been happening towards a greater understanding of indoor air quality, too. The level of indoor pollutants in most houses is usually two to five times higher than that of outdoor levels, dubbed a ‘toxic cocktail’. While people are spending up to 90% of their lives indoors, indoor pollutants can be more damaging to health than outdoor pollution.

This was the premise of our latest Associates meeting, in which we met to discuss health, with the aim of understanding the trends and challenges around designing for indoor air quality — an increasing concern in our air-borne pandemic. Our guest was Tom Woolley, British author and architect in Northern Ireland, Chair of UK Clean Air Steering Committee who specialises in indoor air quality and expert on designing with green and nature-based materials.

Tom explained how much more consideration is needed for design and specifications choices, “People are ingesting a range of chemicals both through what they eat, as well as what they breathe inside buildings — volatile chemicals and chemical pollution being released from a wide range of sources.”

, you can measure volatile organic compounds and formaldehyde in buildings. Generally speaking, these kits garner results that indoor air pollution is well above the ‘safe’ limit. A major variable is measuring the chemicals people bring indoors, such as chemical cleaning products, scented candles and air fresheners; and pollutants that exist from the choice of building materials.

Key offenders can be:

  • Flame retardants, which are serious, toxic, carcinogenic emissions in buildings. A study done by 
  • Phenol formaldehyde resins (PFA) is another one, as featured in the film Dark Waters (2019). PFA is perhaps best known for its use in non-stick pans. But 
  • Petrochemical insulation materials that are used in buildings are a serious source of indoor air pollutants. Worse still, there is an assumption that this is locked up behind concrete, but in reality, off-gassing is detected from insulation materials, emitting at very high levels when the materials are first installed and lingering in the building for many years.
  • Mould from darkness, which is becoming more and more of a problem in the UK. Partly due to fuel poverty, but also due to the hundreds of thousands of botched insulation schemes that have been installed and continue to be installed in houses.
  • Screeds, especially fast-drying, which are very high in hazardous chemicals. Often used in conjunction with toxic adhesives.

What to do?

  • Purge the air from your home every morning. Less people in the UK are making this daily practice, due to concerns around maintaining heat for environmental and cost-effective reasons.
  • Try specifying hempcrete. While Tom appreciates that the hemp and lime mix is a niche movement, the biobased material can be installed using basic tools and is free of hazardous chemicals. In environmental circles it’s growing in popularity.
  • Inform yourself. ICF, Insulating Concrete Forms, while being dubbed ‘good’ for the environment, remains on Tom’s banned list.
  • Watch out for marketing gimmicks. Tom reminds us that even something as simple as gypsum plaster board these days is full of contaminants because it’s made with recycled materials from power station waste, rather than natural gypsum. And that materials companies will go to great lengths to woo architects and designers into specifying their products
  • Try and reduce the use of plastics in buildings and you have a bigger chance of reducing emissions and toxins. For inspiration, read more about the .
  • Get behind the Town and Country Planning Association (TCPA) .

And, as ever, keep talking to the Quality of Life Foundation. For an essential guide to best practice, and its key lessons in maintaining healthy internal environments in modern low energy homes, try: .

Additionally, Tom will soon be authoring a new book on indoor air quality, Natural Building Techniques: A Guide to Ecological Methods and Materials will be available early in 2022 published by Crowood Press. Meanwhile you will find his existing book on .