Winter Home Health: Why Indoor Air Quality is Important in the Winter Months

As temperatures drop in winter months, inhabitants inevitably want to tightly seal their homes to keep out the cold. This can involve increasing insulation in walls and other cavities in the home, weatherstripping and using caulk to seal cracks and crevices. As homes are more tightly sealed, ventilation decreases. This can raise the concentrations of allergens, pollutants, and possibly even radioactive radon gas in the home.

Another important factor to consider when maintaining indoor air quality is the “stack effect.” This phenomenon is the same mechanism, or force, that causes hot air balloons to rise. As warm air rises, air from the lowest levels are drawn up into the living spaces of the home, introducing basement/ crawlspace air into the living environment and eventually out of the roof or attic. It is estimated that 40% of the air we breathe in the living areas was once basement/crawlspace air.

As the cold season draws near, there are a few indoor air contaminants/pollutants that should be given special consideration:

Combustion Pollutants

Combustion sources include propane, oil, gas, kerosene, coal and wood. Any combustion appliance that uses these fuels can lead to indoor air pollution.Such appliances include natural gas and propane heaters, wood-burning stoves, fireplaces, water heaters, dryers (if gas-powered), and stoves, and they all should be vented. It is critical that these appliances are well-maintained and checked by a professional during a tune-up every heating season.

Carbon monoxide and nitrogen dioxide are the most dangerous emissions from the combustion sources mentioned above. Carbon monoxide is odorless, tasteless, and colorless. It interferes with oxygen distribution in the body. Symptoms of carbon monoxide poisoning include poor coordination, headache, nausea, confusion, dizziness and fatigue. High levels can cause death. The Center for Disease Control (CDC) reports that during 1999-2010, a total of 5,149 deaths from unintentional carbon monoxide poisoning occurred in the U.S., an average of 430 deaths per year (CDC, 2010). It is extremely important to install a carbon monoxide alarm that will alert occupants to the presence of this deadly gas. Often these alarms are combined with smoke detector capabilities as well. Nitrogen dioxide is also colorless and odorless, and it can irritate the mucous membranes, including those in the eyes, nose and throat. Additional effects include shortness of breath, damaged respiratory tissue and chronic bronchitis.

Radon

in the home where people spend the most time. Because radon has no taste, smell, or color, a home must be tested to find out if there is a presence, and if so, how much radon is in the air. There is no safe level for radon, but the EPA and the Surgeon General recommend fixing homes that have levels at or above 4pCi/L (picocurie per liter). Radon is found throughout the U.S. and can vary widely from one home to another. Homes with high levels have been found in all states. Home radon testing is simple and inexpensive. Many state radon programs, as well as Montana State University Extension's Housing & Environmental Health Program, offer radon test kits, and there are inexpensive ways to fix and prevent high radon levels in homes. Effective mitigation can be done by the homeowner or professionals.

Mold and moisture issues

Mold requires moisture to grow and proliferate. When areas in a home, such as kitchens, bathrooms, basements, and laundry rooms are humid or experience water damage, mold can develop in a relatively short period of time. Mold problems in winter can quickly develop in walls and on exterior windows that aren’t insulated. Although the accumulation of mold is prevalent all year round when left unchecked, it can be especially bad in winter or early spring. This is because many homes are tightly sealed against the cold outside, so any moisture that does develop or find its way inside, can remain inside for a long time. Also, with the difference in temperatures between inside and outside, condensation on windows and walls is more likely to occur during this time period.When occupants are exposed to mold, it can irritate the lungs, and trigger or exacerbate allergies and respiratory issues. However, homeowners can combat mold with a bit of effort. The easiest way to begin addressing mold growth is to reduce the moisture that mold needs to grow. Focus on common moisture-prone areas inside a home such as bathrooms and the kitchen. Bathrooms and kitchens should have operable exhaust fans that draw moist air out of the room. Heated Recovery Ventilation units (HRVs) can also assist in regulating

moisture while optimizing the conservation of heat from exiting air. Also check the area outside of a home for leaks and rain gutters that may not be operating properly. Both inside and outside the home, it is important to address water and moisture problems as soon as they are found.

Allergens

Dust mites These microscopic bugs flourish in mattresses and bedding. When their droppings and remains become airborne, they can cause allergy symptoms.

Mold This fungus thrives in damp, humid areas such as basements and bathrooms. When mold spores get into the air, they can trigger allergy symptoms.

Animals Most people are not allergic to animal fur, but rather to a protein found in the pet dander, saliva, and urine.

Lastly, it is important to keep in mind that it’s in the winter months that many people choose to work on hobby and home improvement activities. With the decrease in ventilation during the cold periods, fumes and other volatile organic compounds commonly found in hobby, home improvement paint/ glue products, household cleaning and even beauty products, can build up to dangerous levels. To keep air safe while using these products, always work in a well-ventilated area. �