Biological pollutants in the home
by Norman Aceron Garcia
Due to the current COVID-19 pandemic, it is now necessary that we follow our health officials’ recommendations on social distancing and self-isolation. In doing so, we must ensure that our homes are healthy as each of us has a role in preventing the spread of the virus. Biological pollution is often attributed from exterior environments, but it can also be a problem where we least expect it, in the place we may have believed was invulnerable – our home.
Research has shown that indoor air can be even more contaminated than outdoor air. Because of our cold climate, many Canadians stay indoors up to 90 per cent of their time, hence, increasing the risk of developing health problems to vulnerable people like infants, young children, the elderly, and those with chronic diseases.
Biological pollutants are substances that come from living organisms. They encourage poor indoor air quality, which can cause several days absent from work, school, social gatherings, and medical visits. Biological pollutants are often invisible, can transmit through the air, and can even damage surfaces inside and outside your house. The most common indoor biological pollutants are moulds, mildew, infectious bacteria, viruses, pollen, animal dander (microscopic scales from hair, pet furs, feathers, or skin), dust mites and cockroach parts.
Many of these biological pollutants are inside every home and it is difficult to completely eliminate them all. Even a seemingly unblemished home may still permit the spread of biological pollutants. Biological pollutants may be found in a dirty furnace, dirty air-conditioner, dirty ducts, a bathroom without a vent or window, a kitchen without a vent or a window, a laundry area with an unvented dryer, an unventilated attic, a damp carpet on a basement floor, bedding, a closet beside an exterior wall, an unclean pet; and unattended water damage in walls and ceilings.
Biological pollutants can trigger allergic reactions, hypersensitivity pneumonitis, allergic rhinitis, and asthma. Among the common symptoms of health problems initiated by biological pollutants include watery eyes, shortness of breath, coughing, sneezing, dizziness, tiredness, fever and digestive complications. Allergic reactions happen only after recurrent contact to a specific biological allergen but they may occur again after re-exposure, or after numerous exposures over time.
There are two major causes that help generate conditions for growth of biological pollutants: nutrients and persistent moisture with poor air ventilation. Be aware of the presence of materials that contain nutrients that permit biological pollutants to grow such as dust, firewood, and construction materials (wood, wallboard and insulation). Inspect the condition of appliances that add moisture to the air such as humidifiers, propane heaters, washers, clothes dryers, dishwashers and gas stoves. Look for musty odours and moisture on hard surfaces, attics and crawlspaces, basements, bathrooms, carpets, heating and air-conditioning ducts, humidifiers and dehumidifiers.
The quantity of moisture that the inside air can hold depends on the air temperature. During summer when the temperature is high, the air is humid and can hold more water. However, as the temperature drops during the winter season, the air becomes drier because it is less capable of carrying water than higher temperatures. This is the reason why, during winter season, moisture condenses on the cold surfaces of windows and poorly insulated exterior walls.
- Repair leaks and seepage. Water leaks in plumbing pipes and washroom fixtures can provide a breeding ground for biological pollutants to grow.
- Install a vapour barrier over dirt crawlspaces to prevent moisture from coming in from the ground. Make sure that crawlspaces are dry and well ventilated.
- Turn on bathroom and kitchen exhaust fans to move moisture to the exterior.
- Pay special attention to carpet on basement floors as it can absorb moisture and serve as an abode for biological pollutants to grow. If you are installing carpet over a basement concrete floor, it is necessary to install a vapor barrier and sub-flooring to minimize moisture problem.
- Have heating, ventilation, and air-conditioning (HVAC) units serviced and cleaned regularly, as these units may likewise become a source of biological pollutants if they are not properly maintained.
- Remove mould from all affected walls, ceilings, and floors using cleaning chemicals that are easily available in most hardware and grocery stores. Paint, stain, varnish, or a moisture-proof sealer should not be used to cover up the moulds, as they may just resurface.
These are some simple and practical ways that you can do to help eradicate biological pollutants and prevet its reoccurrence. These recommendations are not exhaustive and may not be applicable to every house. Do your research and seek advice of professionals to determine the appropriate solutions for your house. Stay safe and may you and your family be free from biological pollutants.
Norman Aceron Garcia, P.Eng. is an accredited professional in Leadership in Energy and Environmental Design specializing in Building Design + Construction. In 2015, Norman founded Mr. Peg Property Inspections, a social enterprise that advocates green building design and climate change adaptation strategies.