Fire and physical safety aside, can you think of single thing more fundamentally important to your health within your home than the purity of the air? Build tight, ventilate right — it’s a long-held tenet of reputable builders and tradesmen. NZEB guided new builds and deep-renovations have seen the arrival of mechanical ventilation with heat recovery (MVHR) as a standard inclusion, managing the quality of the air we breathe in our sealed-up homes.
Domestic Indoor Air Quality (IAQ) is an urgent matter in progressive building, environmental and scientific circles around the world. In past decades, what are termed air-exchanges, took place passively — streaming in and out through gaps in the building, via the passive stack ventilation of an open chimney, through trickle vents in the windows and so on.
Now, our homes are being designed, engineered and finished in a highly specific way — to stop uncontrolled air exchanges and deliver only fresh, filtered air strained of pollutants and allergens like pollen. Whether you’re in a traditional house, leeching air through poor weather sealing, or tucked up in an A3 super home — don’t blithely ignore your IAQ.
Dr Marie Coggins, Exposure Science Lecturer at School of Physics, NUI Galway, explains, “Indoor air quality plays a very important role in human health. The average European spends upwards of 60%of their time indoors, and younger children and the sick can spend periods of 100% of their time indoors. Typically, the indoor concentration of many pollutants is higher than outdoors. We seem to be less bothered by indoor air pollution, probably as we have more control over sources and levels.”
The main culprits when it comes to worrisome concentrations of pollutants indoors include some expected and less unexpected sources including of course radon gas. These uninvited guests arrive with things we introduce incidentally, and what reaches us from outside air, through the earth, and to a lesser extent on our outdoor shoes.
Dr Coggins continues: “When smoking occurs indoors it dominates as a source.”
There is a “synergistic effect” between radon and tobacco smoke that can lead to lung cancer — worrying if there is a potential radon problem in the building, radon.ie. “We know that burning fossil fuels can release indoor pollutants,” Dr Coggins continues, “such as PM2.5” (particulate matter with a diameter less than 2.5 micrometres - small enough to be inhaled deeply in the lung).
“In the EPA STRIVE-funded study called Indoor Air Pollution and Health (iapah.ie) we measured PM2.5 in homes that used different fossil fuels for heating and cooking. We measured higher concentrations of PM when starting and refuelling the fire. Levels also tended to be higher in homes burning peat.”
“If you live in a polluted area,” Dr Coggins explains, “some of the outdoor air pollutants will infiltrate through the building structure and via open windows and doors. Outdoor air pollution in Ireland tends to be higher in areas where fossil fuels are used, and can reach very high outdoor concentrations on cool still winter evenings.”
Dr Coggins’ word is backed up by some startling results in a joint project involving Cork City Council and the Centre for Research into Atmospheric Chemistry (Crac) at UCC in early December of 2019. For a moment in time, areas of Cork had the poorest air quality recorded in Europe. Simply opening windows in a polluted urban situation can make the IAQ worse according to Dr Coggins, so manage this problem from within with good cleaning practises and ventilation. Nurture cleaner air indoors and appropriate air exchanges.
Air purifiers sized to the space working primarily with fine HEPA filtration can capture up to 99.97% of PM2.5 and PM10 particles and offer several air changes in a room over one hour Some also deal with gases. Some ioniser types create a significant ozone burden— research. Blueair machines in the €300-€600 range have a high reputation for removing minute airborne allergens and pollutants
Off-gassing is the discreet release of volatile organic compounds and other chemicals into the air from largely new things we bring indoors including brominated flame retardants that can get into the air as dust. New house? New furniture? New baby? You should be aware of the process.
Dr Coggins explains, “Indoor furnishings can often be a source of many chemical pollutants depending on how they were made (glues, paints or adhesives used in pressed wood furniture) or the chemicals (e.g. flame retardants) which have been added to textiles and foams to improve flame retardant properties. When products are new they tend to ‘off gas’ or leach out larger amounts of pollutants. This rate also depends on air temperature and relative humidity, but in general over time levels of off-gassing reduce.”
Cleaning has become an influencer-aided religion. A survey by the EU international Association for Soaps, Detergents and Maintenance Products in 2017 found that while 82% of that question felt that having a clean home and clean clothes were as important as being in good health, having financial stability and positive relationships, 56% never read the label on a detergent product. If you’re pleasurably inhaling the faux meadow/floral chemical artistry of commercial sprays and room fragrances – you might want to hold your breath.
“Almost all household cleaning products contain VOCs,” Dr Coggins argues.
Moisture or damp is also a source of indoor air pollution, dust mites, bacteria and mould like to grow on damp surfaces and overtime will emit spores or other toxins indoors” adds Dr Coggins. Again, be proactive.