You can go online each morning and check your city’s daily air quality, the allergen rating and the ozone levels. But while you may know exactly what your hometown’s air is like, you probably don’t consider what’s lurking in the air inside your home.

Because most people spend more time inside their home than in the outdoors, indoor air quality is an important and often overlooked consideration for the general health of everyone in your household. The Environmental Protection Agency (EPA) estimates that, depending on where you live, your indoor air is two to five times more polluted than outdoor air.

Why is the average American home’s air so dirty? While a variety of factors and behaviors contribute to each home’s individual air quality profile, the increased energy efficiency of homes is one major reason indoor air has become a problem, says Lisa Cleckner, Ph.D., assistant director of operations at the Syracuse Center of Excellence in Environmental and Energy Systems.

"Conventional thought is that as buildings were made tighter in the 1970s for energy efficiency reasons, the problems of adverse indoor air quality became more common because not as much fresh air was entering homes, offices, schools and other buildings," explains Cleckner. "People are becoming more aware of the issue and are paying more attention."

But while the problem is widespread, the causes vary from household to household, depending on the region you live in, your household’s habits and even your house itself.

"There’s no one test for indoor air quality issues," explains Michael Dooley, certified home inspector and owner of ESI Inspections in Albuquerque, N.M., an environmental consulting and inspection firm that specializes in air quality inspections. "It’s like detective work—you often see the symptoms of a problem with health issues or home problems, then you have to work backward to determine what’s causing it."

Here are a few common culprits of indoor air quality problems and what you can do about them.

Indoor Air Quality: Is Your Home's Air Safe?
Improper ventilation can encourage the growth of mold behind wallpaper and drywall.

You don’t have to be the victim of flooding to have a mold problem in your home. A leaky window, an improperly vented bathroom or even a pipe with faulty insulation can cause the notorious fungus to thrive in your home. While not everyone experiences physical symptoms associated with mold problems, those who do can really suffer when it enters the home environment. "Everyone reacts differently to it," Dooley says, "but if you have a mold problem in your home, those who aren’t affected by it right away can build up a sensitivity that can cause problems."

Mold often shows itself in obvious ways like discolorations, spots of spores or even as bubbles in wallpaper or drywall. But if someone in your home begins to feel sick while inside the house and better when not there, mold will probably be one of the first things to look for as a culprit because it is so common. "It can grow in 24 to 48 hours, and homes have lots of materials like Sheetrock® and wallpaper that really encourage growth," says Dooley.

If you spot a mold problem, don’t reach for the bleach: the EPA recommends using regular detergent for basic remediation. If you have a big problem, however, it’s best to call in a professional to get it fixed correctly. Specialists in carpet and rug cleaning or fire and water restoration usually work on mold remediation, as well, and are generally listed in the phone book. Your certified home inspector may also be able to recommend someone.

Formaldehyde and Other Volatile Organic Compounds (VOCs)
If you thought you left this noxious-smelling chemical behind when you left sophomore biology, think again. Formaldehyde lurks in many products for the home, including most composite wood (pressboard) products and furniture, including subfloors.

When it’s subfloors or new cabinets that are making you feel sick, ripping them out and starting anew probably isn’t the most cost- or time-effective solution. You can remediate, however, by allowing the products to "off-gas" in a well-ventilated area or, if they’re already installed, by airing out the house, says Sam McLamb, president of SafeHome Filters, an Asheville, N.C., company that produces specialized air filters for residences. "People love the ‘new’ smell, but really, that smell is a sign that there are chemicals off-gassing that aren’t good to breathe," he says.

Another source of VOCs is indoor paint. Orit Yanai, a San Francisco-based LEED-certified master applicator and consultant who specializes in artisan wall coverings, says the move toward more organically based wall finishes is well underway simply because people are concerned about VOCs and their health. "Green wall finishes are far more beneficial for indoor air quality," Yanai says. "Lime-based and clay-based materials even reject dirt and pollen and won’t stick to walls, and are mold-resistant, as well."

Smoke and Candles

Indoor Air Quality: Is Your Home's Air Safe?
Candles pose a risk both for the lead that may be contained within the wick and the fragrance they give off. Photo Credit: Wikimedia Commons

It may sound relaxing to light a few candles after a long day, but it can have a negative effect on indoor air quality in unexpected ways. "Candles release particles when they burn, and researchers have found elevated levels of lead in wicks from some candles," says Cleckner.

Another concern with household candles are the fragrances they can emit. Many people have sensitivities to the chemicals that create the aromas. In one California study, 80% of the respondents reported a sensitivity to some fragrance. Cleckner says aromatic candles and indoor air fresheners are "hidden" home pollutants many people don’t think about. And while they may seem minor, these hidden pollutants can add up, particularly in sensitive populations like small children.

"Children are more vulnerable because of their size and because many of their organ systems are still developing," says Cleckner. "Also, they spend a lot of time on the floor where particles settle. And they tend to put things in their mouth, leading to direct oral exposure to pollutants."

Unseen Hazards: Carbon Monoxide and Radon
While carbon monoxide and radon are colorless, odorless and extremely hazardous, they are preventable hazards. "Radon is generally tested for when houses are sold, and plug-in carbon monoxide detectors are available," Cleckner says, adding that it’s a good idea for households to invest in these inexpensive devises.

Beyond testing for the presence of carbon monoxide, altering behaviors, like not idling a car in the garage and safely using gas heat sources, are proactive ways to prevent tragedy. Make sure gas heat sources are properly vented and lines are leak-free, as well.

Sniffing Out Problems in Your Home
The first sign of an indoor air quality problem is usually a health issue with a household member. If someone is experiencing headaches, body aches, lethargy or other symptoms while at home that seem to get better once they leave the house, it’s time to get your air quality checked. It’s also important to keep tabs on your home’s air health if any household member has a compromised respiratory system or spends a large majority of his time inside the home because these people are more affected by the home’s air quality. The quality of your home’s indoor air is especially critical for babies and small children not only because their bodies are smaller and their respiratory systems are less developed but also because they have a higher respiratory rate, McLamb says.

The best way to check your home’s air quality is to consult a professional. "The difficult aspect of indoor air pollution is that many of the chemicals that volatilize from these products are very reactive," says Cleckner. "In the presence of light, heat and particles, these gases can combine to form other pollutants that are more hazardous than the original compounds. Since many homes have different indoor pollutant sources present, each indoor environment is likely to have a unique problem set of pollutants."

Look for a certified environmental inspector or check the Indoor Air Quality Association site to search for IAQA members within the U.S. Or, visit the American Society of Home Inspectors site to search by specialty for an environmental consultant in your area.

Credit: Renovate with Tommy Mac