An estimated 9,500 people in London die each year due to poor air quality. The findings in a study carried out by researchers at King’s College London attribute the premature deaths to pollutants known as PM2.5s and the toxic gas nitrogen dioxide (NO2). Emissions from cars, planes and heavy industry are widely known to have a detrimental effect on the exterior air we breathe, but is our interior environment becoming equally as harmful to inhabit?

We spend 90% of our lives indoors due to a combination of home, work or school commitments. As for the buildings we inhabit, they are being built to regulations designed to make them as airtight as possible in order to reduce emissions from fuel usage and increase our comfort and wellbeing. But in sealing the thermal envelope on our homes and offices, are we opening ourselves up to dangers previously unconsidered? It would appear so. According to the World Health Organisation, Indoor air quality is up to five times more polluted than typical outside conditions. Reduced air leakage – although key to attaining regulation U-values – could also be affecting the indoor air we breathe, as a lack of natural ventilation allows concentrations of indoor air pollutants to build-up rather than escape.

Harmful sources

Toxic gases within the home can be emitted from a number of sources including emission-generating air purifiers, water treatment systems in washing machines and appliances that use UV or unnatural light. Home cleaning and personal care products also release harmful airborne chemicals, whist some interior paints contain volatile organic compounds (VOCs) which can be released into the atmosphere many years post-application. Cooking appliances such as ovens and toasters, if not regularly cleaned, have also been found to produce particles that fill interior air.

The aforementioned emissions are exacerbated in multi-occupancy buildings. Where ventilation is poor, this will intensify the trapping of appliance-based toxins, whilst vapour created from baths, showers and general washing duties increases the risk of condensation occurring. This in-turn runs the risk of introducing another harmful element to the indoor environment: damp. According to a public heath report by academic studies’ specialist MDPI, exposure to indoor mould contamination instigated by damp in social housing increases the risk of doctor-diagnosed asthma, particularly in older adults and women.

Improving living standards for the health and wellbeing of residents in poorer UK communities is an issue Recticel is seeking to address through its membership of the National Home Improvement Council. The non-profit organisation was set up nearly 50 years ago to promote the benefits of safe and sustainable homes as a means of creating comfortable, affordable interiors. This is particularly aimed at occupants facing fuel poverty, a threat that’s been exacerbated for many households nationwide due to the current worldwide rise in energy prices.

Importance of good ventilation

Figures released by the Committee on Climate Change show emissions from buildings account for 34% of total UK greenhouse gas emissions. It is a statistic that is no doubt being unnecessarily fuelled by the poor thermal performance of the country’s housing stock. This is borne out by a 2017 Green Council Report which found that 25 million UK homes will need to be refurbished between now and 2050 in order to meet mid-century insulation standards.

However, when looking to improve a building’s energy rating, there is a balance to be struck. Airtight buildings need to be properly ventilated in order to improve indoor air quality. This can be achieved effectively with a heat recovery ventilation system, which extracts moist and stale air from a property’s wet rooms and recovers the – usually – lost heat from the extracted air.

Therefore, with modern building methods, tighter regulations and improved efficacy of a building’s fabric, it’s often the case that a correctly-specified mechanical ventilation system also needs to be considered when improving a property’s thermal envelope.  An airtight house without adequate ventilation can suffer the same issues as one with too little ventilation, as both create uncontrolled airflow. This can result in condensation issues – and eventually damp or mould patches – due to air being moved from areas of high humidity within a building such as the kitchen and bathrooms, to bedrooms and main living room spaces where the air tends to be cooler and dryer. A mechanical ventilation system helps ensure the correct amount of air flows consistently through a building by extracting it from areas of high humidity and returning it to living areas.

Our future built environment’s sustainability depends on improving the airtightness of the buildings we live, work and learn in. But we must safeguard against cocooning ourselves in spaces that are potentially harmful to our long-term health. Hence, a professionally-prescribed ventilation solution will be crucial to us leading happier, more comfortable lives on the inside and outside.   


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BDC 311 : Dec 2023