An Attempt to Clear the Air
By Chris Burch
Indoor Air Quality:
Purchasing a home is the largest single investment most people will make in life. Maintaining the home with timely repairs must be a priority for homeowners who want to protect their substantial financial investments. People typically focus on the most obvious and visible home improvement and maintenance needs, and miss what they cannot see. One less apparent aspect of a home’s health is its indoor air quality. The Environmental Protection Agency (EPA) states that indoor air is typically two to five times worse than outside air, and it is estimated that people spend nearly 90% of their time indoors.
According to the American Medical Association, one-third of the United States National Health Care Act addresses causes directly attributable to indoor air pollution.
The EPA defines Sick Building Syndrome (SBS) as a situation in which building occupants experience acute, negative health and comfort ailments that appear to be linked to time spent in a building, but in which no specific illness or cause can be identified. Eye, nose, and throat irritation, headaches, fatigue, dizziness, nausea, shortness of breath, and muscle pain are some of the symptoms of Sick Building Syndrome. Many medical professionals believe that longer-term health problems related to poor indoor air quality may include heart problems, respiratory issues (including asthma), and certain forms of cancer. It is worth noting that there is much debate on the subject, and experts continue research to identify the contaminants and their health effects.
Indoor air pollution can come from a number of sources. Those sources include the following:
- Carpet and glue off gassing – the release of particles from carpet and glue components
- Pain that contains Volatile Organic Compounds (VOC’s)
- Household cleaners and disinfectants
- Gas ranges that emit carbon dioxide and nitrogen dioxide
- Wood cabinets and furniture that contain formaldehyde
- Pesticides used indoors
- Personal care products that contain harmful chemicals
- Pet dander
- Mold (mycotoxin)
In the last several years we have seen a construction trend toward more stringent building codes. When following these codes, builders use more energy-efficient windows and doors, and foam insulation in attics, exterior walls, and crawl spaces. These trends have exacerbated the indoor air quality problem. While these changes favor a reduction in energy use and cost, the down side is that some homes are considered “too tight,” or, in other words, not breathing enough. Homes need fresh, outside air.
Mold problems deserve more attention.
Mold is part of the natural environment and we would not survive without its existence. We find mold outdoors and indoors, and it cannot be completely avoided. People are exposed to molds 24 hours a day, seven days a week, 365 days a year. It is usually not a problem unless it is growing inside a building. Although it is estimated that there are over 100,000 species of mold, only approximately fifteen species are considered dangerous. The most well-known and toxic is “black mold” (Stachybotrys Chartarum).
For mold to grow, moisture and a nutrient base must be present (drywall, wood, etc.), within a temperature ranging from 40 to 100 degrees Fahrenheit. Molds produce microscopic spores that spread easily through the air. Shoddy construction, lack of maintenance, plumbing failures, hidden leaks, inadequate ventilation, and high indoor humidity cause and contribute to indoor mold growth.
One of the most important components to a building system is the heating, ventilation, and air conditioning (HVAC) system. The HVAC system functions to control air temperature, humidity, cleanliness, and distribution. The system should be energy-efficient while providing thermal comfort, acceptable indoor air quality (removing contaminants and odors), and ease of operation and maintenance.
There are moisture challenges. If the air is excessively dry, comfort problems will be present (dry skin, nose bleeds, nasal congestion, and thriving opportunities for the spread of germs). Excessive humidity is conducive to mold growth.
What can you do to assure your home’s indoor air quality is acceptable?
Water is key. Keep your home dry and clean. Do routine inspections of the entire home. If your home interior does get wet, you should dry it out quickly as possible. Some molds start to grow within 24 to 48 hours.
If mold is present in a building, it can be distributed through the ductwork. Have the HVAC air handler coil inspected and cleaned at least once a year, as mold can grow on dirt that accumulates on an AC coil. You should consider having the air ducts cleaned if you see substantial visible mold growth on components of your HVAC system.
Do not close off supply registers in rooms that are not used, as that may provide an environment favorable for condensation.
The American Society of Heating, Refrigeration, and Air-Conditioning Engineers (ASHRAE) recommends that indoor relative humidity be maintained between 30% and 60%. Keeping humidity levels below 60% and venting moisture from showering and cooking to the outside are ways to prevent conditions conducive to mold growth.
When building a new home, keep in mind bigger (oversizing the HVAC tonnage) unit is not better. If the unit is oversized when it comes on it will blast plenty of cool air and then shut off. This is called “short cycling” and will result in improper dehumidification of your air. Also, request your builder and HVAC contractor to install return air vents in all large rooms (kitchen and bathrooms are exceptions) as this allows more balance between room-to-room temperatures and reduces moisture build-up on walls and ceilings.
Change out your HVAC filters regularly (every 30 to 90 days based on the manufacturer’s instructions). Filters should have an efficiency rating of MERV 7 or better, but you should consult your HVAC equipment manufacturer for recommendations on the highest level of filter resistance for your HVAC equipment.
Increase the number of air exchanges: ASHRAE recommends a minimum of 8.4 air exchanges per 24-hour period. Adequate ventilation helps reduce the concentration of indoor pollutants in the home. Ventilation has been shown to reduce dust mites, mold, and other culprits that lead to indoor air pollution, while replacing stale air with fresh, cleaner air. I like to open windows and doors whenever possible to allow plenty of fresh air inside my home or office, especially when the humidity levels are low. If you choose to do that, it is key to run the HVAC system for a while after closing your doors and windows in order to lower the humidity back to an acceptable level.
It stands to reason that we should want to breathe the cleanest possible air in the place(s) where we spend most of our time—not only to feel our best, but also to live healthier lives in the long run. Making sure your home is getting plenty of fresh air, maintaining your HVAC system, and ensuring no mold is actively growing inside of your home are three simple, smart ways to achieve cleaner air and a healthier living environment.