Pollutant warning over 'airtight' modern buildings

In the drive to cut energy bills and increase environmental sustainability, architects, designers and facilities managers are increasingly seeking to make buildings airtight.

However new research in Scotland shows that new and refurbished properties designed to be airtight are risking a build-up of harmful chemicals and moisture if people do not use ventilation correctly.

Experts at the Mackintosh Environmental Research Unit (MEARU) have found that modern airtight homes are potentially exposing people to harmful levels of pollutants. Professor Tim Sharpe, Head of MEARU, said: "There are clear links between poor ventilation and ill-health so people need to be aware of the build up of CO2 and other pollutants in their homes and their potential impact on health."

He added that poor indoor air quality, particularly in bedrooms, is hard for people to detect.

A recent study by the Royal College of Physicians and Surgeons on air quality suggested that the issue of indoor air pollution needs research to strengthen the understanding of the key risk factors and effects of poor air quality in our homes, schools and workplaces.

MEARU did research in over 200 properties built to modern airtight standards since 2010. It revealed widespread evidence of poor ventilation, with bedrooms being a particular problem. The findings showed that there was little awareness of poor indoor air quality and its potential consequences.

Nowhere to go

Levels of pollutants can be five times higher indoors than outdoors and when vents and windows are kept closed, the chemicals have nowhere to go. Research into domestic mechanical ventilation found that while it can deliver good results, when houses are entirely reliant on it and it goes wrong, there is extremely poor ventilation.

Pollutants in buildings

Researchers said over 55,000 different materials are used in buildings, including some 12,000 unique Volatile Organic Compounds. Common pollutants include

  • Formaldehyde, used in pressed wood products such as particleboard, plywood, and medium density fiberboard (MDF), paints and coatings.
     
  • Phthalates, used to make plastics like polyvinyl chloride (PVC) more flexible or resilient.. These are known to disrupt the endocrine and reproductive systems and have been linked to liver cancer (CDC 2005).  They are also associated with increases in persistent symptoms of allergies and diagnoses of rhinitis, eczema, and asthma (Mendell 2007).
     
  • Particulates: inhaling particulates can cause eye, nose, and throat irritation and can increase the risk for respiratory infections. Long-term effects of inhaling ultrafine particles (less than 2.5 μm), because they can travel deep into the lungs where they can remain embedded for years or be absorbed into the bloodstream.

In addition, high levels of moisture encourages growth of dust mites - bad news if you have asthma, hay fever or allergies. Moisture also encourages mould spores which cause lung infections in people with weak immune systems.

MEARU is running a public information campaign with a film to inform householders about how to maintain healthy indoor air quality for householders. The film is available on the online video-sharing site vimeo.

Based at the Mackintosh School of Architecture at the Glasgow School of Art, MEARU has a 15-year track record of research into environmental architecture. It operates at the interface between architectural design, science based research and building occupants.