Why is Indoor Air Quality so Important?

Many factors go into the process of building a healthy home for our customers, from sourcing sustainable building materials to ensuring rooms are flooded with natural light. A huge consideration for us is to ensure the best air quality possible inside the developments we build. But why do we do this? Read on to find out…

When you think of air pollution do you immediately think of vehicle fumes and busy roads? Unfortunately, these harmful fumes seep into our homes and whilst inside, we can be breathing just as much pollution as being outside. And seeing as we spend most of our time indoors – at home and work, we need to consider what we can do to make every breath we take inside our homes as clean as possible.

However, it’s not just air pollution from outside we need to think about.

The true extent of possible sources of toxins from within our own homes, from places you wouldn’t expect, such as your mattress, cooker and even ink from print cartridges. These everyday items emit VOCs – volatile organic compounds. What are they? Douglas Booker, CEO and Founder of National Air Quality Testing Services spoke with Doug Fearon and Punit Modha from the Joseph Homes Technical Team to shed more light on these compounds found in our home…




Raising awareness of the toxicity levels in these everyday household items is key to helping make some easy changes to improve air quality inside our homes. Public Health England reported in March 2019 that air pollution is the biggest environmental threat to health in the UK, with between 28,000 and 36,000 deaths a year attributed to long-term exposure. There is strong evidence that air pollution causes the development of coronary heart disease, stroke, respiratory disease and lung cancer and exacerbates asthma.

It’s a serious problem, but one we are trying to improve with the homes we build.

We’re one of the few developers who currently test the indoor quality in our homes. For us, it’s a priority.



We’re pleased to report that both of our recent developments, The Tramyard in Balham and No.1 Millbrook Park in Mill Hill both achieved an A Rating on the Indoor Air Quality scale. We are using this data to inform specification changes and improvements to continually enhance the internal living conditions of the homes we build.

We assess a percentage of the completed homes to measure the internal air quality. We measure:

  • Humidity & temperature: we combine humidity and temperature readings to give an overall rating for thermal comfort.
  • Volatile Organic Compounds (VOC’s): a test for airborne chemicals
  • Microbial Volatile Organic Compounds (MVOC’s): as assessment of any actively growing mould
  • Carbon Dioxide: a measurement of CO2 levels provides an indication of building ventilation efficiency
  • Formaldehyde: to check airborne concentrations fall within recommended guidelines.

So what can we do to improve the air quality in our homes? We’ve heard that having plants purifies the air around us – but is it enough to make a difference? Let’s find out…




And what about the products we buy for our homes? Could we also look to improve our indoor quality by taking more consideration into what we’re bringing into our homes? Douglas explains…



We want all our homes to achieve the highest levels of internal air quality as well as tackle the impacts of external air pollution. We’ll do this by using VOC free paints where possible and looking at other ways we can specify products and materials with lower toxins through the build process. We’ll also be specifying high-grade filters for our MVHR systems to help reduce fumes and pollen entering our buildings.

Our technical and design teams are working hard to understand the best specifications and products on the market which benefit our customers and deliver healthier homes.


As you might have noticed by now, we place great importance on indoor air quality. We strive to use materials that won’t have a detrimental impact on our homeowners and fully understand the part we have to play in ensuring people live well in healthy homes that we build. But it’s still early days for the development industry, something we’re hoping we can start raising awareness about and instigating change to the approach to this subject. Going forward, what else could be done to ensure indoor air quality?



Interested in the conversation around Indoor Air Quality? Here are some further resources to explore:

British Lung Foundation 

Parliament UK

Imperial College London

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