Clearing the Air, About Air Quality.

The current meteoric rise in public concern and interest regarding Air Quality and healthy environments has created an opportunity for industry to market and promote a myriad of diverse products and services.  Everything from scented candles and snake oils to ozone generators and air fresheners are being advertised as the Air Quality answer to all our healthy home needs.

On average, Canadians spend 80% of our time indoors; a great deal of that time is spent in your own home.  Controlling the air quality conditions of our work places can be difficult however, improving your healthy environment at home simply requires a basic understanding of how your home works.  Universally, homes behave as an integrated system, what happens in the basement, affects air quality upstairs.

Unfortunately, a healthy home is not about having more, a healthy home is about living with less; less humidity and moisture, less chemicals and odours, less particulates and dust.  Reducing air quality concerns in our home means living with less irritants our bodies defense systems must address.  Imagine if we were born with a wheel barrel for environmental sensitivities.  During our journey of life each person loads their wheel barrel at a different pace, (Environmental Exposure Level).  Some people have the capacity to fill a larger wheel barrel of environmental sensitivities, (Dose Response).  Some people due to past environmental exposure may not have room in their wheel barrel and may not be able to handle the environmental burden, (Multiple Chemical Sensitivity M.C.S).  The fundamental similarity between all wheel barrels is the universal benefit of environmental load reduction.  We must seize every opportunity to reduce air quality and environmental irritants from our homes in an effort to keep our wheel barrel of sensitivities empty.  If our environmental load is light weight, our capacity to shoulder unforeseen air quality exposures is increased.

If we are to adapt the “less load” philosophy to our own homes we must embrace some life style changes that promote healthy environments.  We must be able to recognize the conditions that generate poor air quality and we must make the correct steps to improve them.  Recognizing these conditions of poor air quality is the first step to improving your environment.

Air quality concerns can be divided into two main categories, chemical and biological.  Chemical air quality concerns are introduced into your environment typically by “off gassing” of manufactured products and materials, cleaners, new furniture, construction materials, solvents, dry cleaning, air fresheners and by products of combustion.

Biological air quality concerns are generally generated, within the building environment.  Biological contaminants may be skin cells and fragments, dander, dust mites, pollen, bacterial, mold and viruses.  Biological contaminants thrive in moist, damp environments.  By controlling the relative humidity levels in most homes, the growth of some of these biological contaminants can be minimized.

Once a homeowner has identified a number of indoor air quality contaminants in the home, a lifestyle change is required to remove them.  This lifestyle change is designed to remove the load or burden on our personal wheel barrel of environmental sensitivities.

We should take the opportunity to reduce exposure to both the biological and chemical loads present in our living environments.  This load reduction is not completed overnight.  Instead, our lifestyle change should incorporate on a daily basis, the philosophy that “less is best”.

There are four strategies that should be incorporated into your lifestyle change:  isolation, separation, ventilation and filtration.  The daily application of these strategies will reduce exposure to air quality contaminants, create an environment with less burden to our personal wheel barrel of environmental sensitivities and create a healthier environment.

“Isolation” is a strategy where the term source control applies.  If we can identify a condition in the home which contributes to poor air quality, the isolation strategy requires complete removal of that condition.  Isolate the pollutant source from the living environment.  (If we have a moldy box of books, remove and discard it).  If we have a leaking pipe adding moisture to our environment, repair it.

“Separation” strategy may be storing malodorous items in a sealed container.  Encapsulating the pollutant source and separating the off gassing item from the environment, while that item is stored within the home.  Required solvents, cleaners, paint cans, can be stored in a sealed plastic container for future use.  Separation may also include the use of impermeable separation membranes to reduce moisture penetration within the building envelope.  Waterproof membranes applied to the foundation to eliminate moisture penetration and separate the building envelope from dampness, is an example of separation strategy applied to the building envelope.

“Ventilation” strategy refers to the three types of ventilation available to most homes.  Ventilation is the exchange of interior air with exterior air.  Ventilation is a means of diluting the higher concentrations of air bourne contaminants and moisture generated inside the living environment.  Imagine our home represents a sealed glass aquarium we inhabit.  Inside this aquarium is a constant sandstorm of very small particles we breathe, (respirable suspended particulates – RSP).  If we were to create an opening on one side of the aquarium and let fresh clean air in, and we were to place an exhaust fan on the other side of the aquarium blowing out, we would eventually dilute and exhaust the higher levels of RSP found inside the aquarium.  This example is how we should perceive the benefits and necessity of a sound ventilation strategy in our own homes.

Effective ventilation can be achieved in three ways. First is simply to open the windows and introduce fresh air.  This is an excellent, easy method of achieving air dilution and air exchange.  During cooler months, leaving windows open is no longer reasonable. We now must begin to depend on mechanical means of ventilation.  The second means of ventilation relies on the “exhaust only” approach to air exchange.  Range hoods and bathroom fans mechanically exhaust air from the environment and achieve ventilation by exhausting air quality contaminants through the fan mechanism and outside the building envelope.  This exhaust only fan system creates less air in the home and develops a slight negative pressure to the living environment.  Fresh air is reintroduced to the home through cracks in the building envelope and the effective leakage area.  This type of “exhaust only” ventilation is most common.  New homes have building code standards that govern the size of exhaust only devices installed as the principle means of ventilation.

The whole house ventilation system is an integrated system of balanced filtered air in and balanced air out, creating no pressure differentials within the home.  These systems can be installed with “heat recovery” technology to save the heat from the air being exhausted (HRV).  All three types of ventilation systems perform the same function, the removal of the higher concentration of air bourne contaminants from inside the building environment.  The dilution of the building air and the exchange with outside ambient air.

The fourth and final air quality improvement strategy should be the use of air filtration.  Mechanically forcing household air through a quality furnace filter or filter media device to scrub or entrap air bourne particles.  Forced air furnace systems are an ideal way to filter household air on a continuous basis.  Switch the furnace fan operation from “Auto to ON” and have the furnace fan run continuously while incorporating a quality furnace filter on your air handling unit.  If your home is not equipped with a forced air furnace, a stand alone HEPA (High Efficiency Particulate Arrestor) filtration device may help.

Although these air quality and healthy home recommendations may seem overwhelming, once you have embraced your healthy home lifestyle changes, the benefits are noticed immediately.  Efforts should be made to reduce your environmental exposure load and ventilate your home at every convenient opportunity.

If you “isolate” moisture and remove the air quality concerns you are aware of – if you “separate” moisture and “off gassing” chemicals – if you ventilate and dilute air quality conditions at every opportunity, and if you filter or scrub the homes air continuously, you will live in a much healthier environment.

A great source of healthy home and air quality information, can be obtained from Canada Mortgage and Housing Corporation (C.M.H.C.) library located at 700 Montreal Road or at their website www.cmhc-schl.gc.ca

Written By:  Shawn Rankin – Indoor Air Quality Ottawa

Published in HealthWise Ottawa – Fall 2007