Your building envelope is signed, sealed and delivers, but ... Sam McLamb looks beyond the benefits of an energy-efficient building and examines what happens when indoor air stays indoors.
Can energy efficiency be hazardous to your health?
The answer is a resounding 'yes' according to the U.S. Environmental Protection Agency (EPA), major universities and many state health departments. Efforts to improve energy efficiency in recent decades have had a direct impact on indoor air quality and health. Although the U.S. EPA ranks poor indoor air quality as one of greatest public health threats, it can be corrected without breaking the bank or a sweat.
Since the energy crisis of the 1970s, Americans have done a great job of sealing homes for energy efficiency purposes. The energy consumption of homes has decreased 30 percent between 1972 and 2006, from 8,655 trillion BTUs to 6,043, according to the Energy Information Administration.
Unfortunately, these same efforts have led to declining indoor air quality. Hazardous gases that once leaked out of a home are now sealed in along with conditioned air to create an unhealthy environment. In fact, the U.S. EPA has consistently ranked indoor air quality as a greater public health threat than hazardous waste sites, outdoor pollution and contaminated drinking water. After all, we spend almost 90 percent of our time inside.
Why does this matter? Our health, welfare and our economy are three reasons. Asthma rates have increased 300 percent in the past few decades. Children and the elderly are particularly at risk. Chronic obstructive pulmonary disease (COPD) is now the fourth leading cause of death in the U.S., and thousands of sufferers are estimated to die every year because of complications due in part to poor indoor air quality. Additionally, decreased workplace productivity due to poor indoor air quality is estimated to cost employers $250 billion per year in the office environment alone (1).
What is the source of these pollutants? Air pollutants are comprised of particles and gases, both of which pose significant health threats.
Particles, such as dust, range in size from microscopic to visible specks in sunlight. Particles are both naturally occurring, such as pollen, and man-made, as from diesel exhaust.
Gases are of particular concern recently because of rising concentrations. More than 70 percent of homes now have unhealthy concentrations of hazardous gases due to the combination of well-sealed homes for energy efficiency and the increased use of gas-emitting materials (household products and activities can release gases into the air). Because gases aren't solid like particles, gases behave completely differently and are unaffected by even the best allergen filters.
You may not realize it, but almost all homes have higher levels of formaldehyde indoors than levels found in outdoor pollution because it is found in so many household products. In fact, the U.S. EPA found significantly higher concentrations of VOCs in homes than in outdoor pollution. These levels can rise to 1000 times those of outdoor pollution during activities like painting.
Many VOCs, such as benzene, are known to cause significant health problems, ranging from respiratory distress to central nervous system damage and cancer. But not all toxic chemicals commonly found in homes are VOCs. The term "VOC" is simply a classification used to designate chemicals that contribute to ground level ozone. For example, many low or no-VOC paints contain acetone, which is highly toxic but not technically a VOC.
While building with nontoxic materials is the fight thing to do for many reasons, this alone may have little impact once the home is occupied. For a list of common sources of VOCs according to the Minnesota Department of Health, see the sidebar on page 19.
So, what can we do? Stop cooking and cleaning? Live in a home with no furniture? Stick our heads in the ground? Not necessary. There are three key steps to achieve sustainable indoor air quality and energy efficiency without sacrificing quality of life:
1. Source control: select products that have no or minimal offgassing
2. Ventilation: allow gases to escape in a controlled manner
3. Filtration: use specific filtration products to trap gases
1. BE PICKY WITH YOUR PRODUCTS
While one may not be able to find or afford nontoxic alternatives for all toxic products and materials, non-or low-toxic options for many products are available at local stores. Many cleaning agencies use nontoxic cleaners; or, you can make your own with a mix of vinegar and water.
Some activities, such as burning candles, release both particles (ash) and gases (VOCs). If you must burn candles, look for soy candles. Carpet also produces both pollutants, so use hardwoods when possible. And avoid using air fresheners, as most release a hazardous concoction of gases.
Don't just air it out. Opening the windows can increase pollutants by letting in pollen, dust, mold spores, ozone and regional power plant emissions like mercury and sulfur dioxide. This also wastes energy if your home air system is trying to overcome the outdoor temperature.
To avoid wasting energy while managing air quality, set up controlled ventilation, such as energy recovery ventilation or positive pressure ventilation. The simple technique of coupling inexpensive filtered air intake with existing bathroom ventilation that pulls air out is used at one of the most advanced 'near zero-energy' homes at Oak Ridge National Labs.
3. FILTER THE AIR AND THE HYPE
Ozone and ionic purifiers: The use of these purifiers is controversial, and the use of them in the home has been banned in a few states. Almost all ionizing 'purifiers' release ozone, which can trigger asthma attacks and long-term respiratory problems. Websites like www.epa.gov and www.health.state.mn.us/divs/eh/ indoorair/voc/can provide you with more information so you can make your own informed decision.
High quality purifiers: Effective air purifiers will utilize High Efficiency Particle Air (HEPA) filters followed by chemical filters containing activated carbon and advanced compounds such as potassium permanganate to absorb gases. HEPA filters alone will not impact levels of gases. Lower quality purifiers often use a thin sheet covered with carbon dust in front of a HEPA filter, quickly rendering the carbon useless as it clogs with debris. Some of the most popular high quality brands include Austin Air and Air Pura. All of these provide high airflow (up to 250 cubic feet per minute) for effectiveness and offer allergen and chemical removal. These are particularly suitable for bedrooms or nurseries. Allergen filters: Though ineffective against gases, there are many great filters available for allergens like dust. However, spending an extra $10 on premium filters is unlikely to create much difference in most homes. Leaks in ductwork or around the filters are going to influence air quality far more than a few extra dollars. Recent research has also shown that electrostatic charges, which trap particles, can degrade quickly, particularly in higher rated filters. Look for filters rated MERV 6 to MERV 9 for most applications.
Chemical or gas-phase filters: Where allergen filters use a physical barrier or electrostatic charges to capture particles, gas-phase filters use activated carbon and powerful compounds like FormaldaSorb[TM] tO chemically bond gas molecules. While certain high quality purifiers are often more effective in a confined space, utilizing gas-phase filters in a central air system purifies far more air per minute and can remove chemicals throughout your home.
The ideal solution requires common sense and a combination of all three strategies. Avoid purchasing and using offgassing products when you can, ventilate the gases when you can't, and remove the remaining contaminants through purification, filtration or both.
SOME COMMON SOURCES OF VOCs
Pressed wood furniture
INDOOR AIR RESOURCES
The EPA's "Guide to Indoor Air Quality," www.epa.gov/iaq/pubs/ insidest.html
VOC sources from the Minnesota Department of Health, www.health.state.mn.us/divs/eh/indoorair/vor/index.htm
PURIFIERS AND FILTERS:
SafeHome Filters, www.safehomefilters.com
Sources: (1) Fisk and Rosenfeld, 1997
Sam McLamb is founder of Asheville-based SafeHome Filters; SafeHome Filters recently introduced the first home air filter replacements that combine allergen and chemical filtration to remove allergens, odors and hazardous gases. Sam has appeared on the 21st Century Healthcare Forum by the U.S. Department of Health and Human Services and in leading journals, including Respiratory Management. He can be reached at 828-667-0730, firstname.lastname@example.org or through www.SafeHomeFilters.com.
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|Publication:||New Life Journal|
|Date:||Apr 1, 2008|
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