Indoor Air Quality: Refers to the air you are breathing in your home or work place. Without consideration for sources of pollution and ventilation, this air quality can become much worse than outdoor air.
Ventilation: This refers to airflow into and out of the building. It can be “passive” as in opening doors and windows or the “stack effect” caused by leaks in the building envelope. It can also be mechanical as with vent fans and air inlets or HRV and HVAC systems.
Building Materials: Carpets, paneling, paint, mastics, and many other common building materials may contribute to poor indoor air quality.
Off Gassing: This refers generally to chemicals that are released by building materials such as foam insulation, paneling, carpet, paints, etc. These can contribute to poor indoor air quality.
VOC’s: Volatile organic compounds are organic compounds which have a significant vapor pressure and therefore tend to be released into the air. These include but are not limited to; diesel, propane and natural gas fumes; sewer gas; wood smoke or other combustion exhaust.
Stack Effect: Stack effect is due to the natural tendency for warm air to rise. This generally creates a condition of positive pressure on the ceiling and upper walls forcing warm moist indoor air out through any breaches in the vapor barrier and negative pressure near the floor and lower walls pulling outdoor air in through any breaches. This can lead to cool floors, frost and moisture damage in attics and many other maladies. This also creates a potential for pulling polluted air into the home from attached garages and crawl spaces.
Radon: Radon is a colorless, odorless radioactive gas emitted from the soil. It is a cause of lung cancer and is common in Fairbanks homes, particularly those in the hills with foundations near or in bedrock. The EPA has established a “safe” standard of 4 pCi/L (pico-curies/liter) for homes. There are several methods for addressing unsafe levels of Radon before and after construction. There are new construction methods that will reduce the potential for soil gasses to penetrate the home indoor air. In the case of existing homes with higher than acceptable radon levels, there are several mitigation methods that can substantially lower indoor radon levels.
Mold: Mold is a type of fungus common in almost all environments. It reproduces with microscopic spores that can float unseen in the air. Most molds require moisture to grow so the presence of mold in a home usually indicates a moisture problem of some sort.
Mold Spores: Mold spores are the reproductive part of mold. These spores are microscopic and float unseen in the air. Human response to mold spores vary greatly from sever health problems to seemingly no response at all.
Attached Garage: The concept of having a garage attached to the house is very popular, especially in cold climate like Fairbanks. This, however, creates perhaps the greatest potential for indoor air quality problems. Cars emit high levels of pollutants, especially when they first start. We also tend to store things in our garages that are polluting, things such as lawn and garden power tools and the fuels for those tools. These pollutants can be pulled into the home air through penetrations between the house and the garage. Heating systems are often placed in the garage and these can be back drafted by stack effect or poorly balanced ventilation systems in the home.
Crawl Space: This refers to the area beneath a floor that is not considered “living” space. In interior Alaska these spaces are often skirted and heated to prevent plumbing freeze ups and to keep floors warmer. Crawl spaces are another common source of indoor air quality problems in Fairbanks area homes. Although not considered living spaces, these areas are intimately connected to the home and are subject to stack effect and other conditions that can pull moisture, mold, radon and other common pollutants into the home.
Vapor Barrier: This refers to a membrane, usually plastic sheathing, placed in a wall, ceiling, floor or on the ground in a crawl space, to retard the flow of moisture in the form of water vapor through that component. This is critical in cold climates because it that moist air passes through a wall or ceiling and reaches the “dew” point it will condense into liquid water and can then cause frost damage or mold. In the case of a crawl space floor, a vapor barrier is intended to prevent moisture and other soil contaminates such as mold spores or radon from entering the crawl space air where it could be pulled into the living space or cause structural damage in the crawl space from rot and mold.
CO: Carbon monoxide is an odorless poisonous gas most often created as a byproduct of combustion as in auto or home heating exhaust. CO reduces the ability of the blood to carry oxygen to the cells. It leaves the body very slowly and therefore even low levels of exposure can be a health concern if the exposure is long term or frequent.
Mechanical ventilation: This refers to ventilation with fans such as range hoods, bathroom fans and such. It is important to balance this forced ventilation with passive inlets to prevent negative pressures that can lead to drawing in of pollutants from the garage or craws space or through breaches in the vapor barrier where they may lead to cold spots or drafts.
Fresh air inlets: These come in many brands and styles and are generally designed to replace ventilation air when bathroom fans, dryers or range hoods are in use.
HRV: This refers to a “heat recovery ventilation system”. This is a form of mechanical ventilation designed to recover up to 80% of the heat that would be lost if you simply vented room temperature outside and replaced it with outdoor temperature air. This is done with a heat exchanger that warms the incoming air by passing it by the outgoing air. This pre warmed air can then be distributed throughout the house.
Filters: The only way to have cleaner air in your home that is outside your home is to filter your ventilation air. This is usually done by a multi stage filter box that is connected to your ventilation system. In interior Alaska we generally have very clean dry air. However, forest fires, volcanoes, temperature inversions, heating system exhaust , pollen, dust and many other things can cause situations where a homeowner might not want to bring unfiltered outside air into the home.
Balanced Ventilation: Bathroom fans, dryers, range hoods, , all force air out of the home. This creates a potential for negative pressure in the home that can draw pollutants from garages, crawl spaces and can pull outside air through walls and other components of the home in ways and places that may be detrimental. It is important to have adequate fresh air inlets to avoid this problem.