If your house were human, how would it fare in a physical exam?
Are tiny dust particles and icky mold spores circulating in its lungs? Are its tissues releasing toxic substances such as radon, asbestos and formaldehyde? Is it having trouble breathing?
We may be unwittingly making our homes "sick" -- and consequently, making ourselves ill.
As we make a list of spring cleaning chores, it's a good idea to include checking and improving the air quality at home, said Iva Cook, support services manager for the American Lung Association of Orange County, Calif.
Cleaning up indoor air reduces the risk of allergic reactions, chronic bronchitis, nausea, headaches, fatigue and breathing problems, not to mention minimizing the chance of slow -- or sudden -- poisoning by toxic gases.
Indoor pollutants can be as ordinary as dust, which can trigger allergies. Or fireplace emissions that can irritate lungs. Or cancer-causing gases that can rise from building materials or from the ground itself.
Keeping indoor air clean is especially important in households where people have medical conditions such as allergies, heart diseases, said Dr. Sherwin Gillman, an allergist at Children's Hospital of Orange County.
Home is where we spend a hefty chunk of our sleeping and waking hours. We're indoors up to 90 percent of the time, according to the Environmental Protection Agency.
The trouble is, we usually don't pay much attention to the air in our homes until we find that it's making us ill.
And this can be true whether your house is old or new, said Dave Thompson, an EPA environmental program manager. Homes built before 1978 are more likely to contain lead-based paint, Thompson said.
Lead, which can be ingested when the paint is disturbed, can cause brain damage.
Asbestos insulation in older homes can cause chest and abdominal cancers and lung diseases.
In newer homes, the emphasis on energy efficiency gives us relatively soundproof and airtight homes.
"But the more airtight the house, the more pollutants it traps," Thompson said.
Many people mistakenly believe they can avoid unhealthy air by staying indoors on smoggy days.
Most of us don't realize that staying indoors also can be unhealthful, an American Lung Association survey last year showed.
Thirty-seven percent of homeowners have a carbon monoxide detector, and only one in 11 has a radon detector. Four in 10 homeowners do not replace air filters every two to three months as recommended.
Sheldon Schwartz consistently replaces the air filters in his home, at least quarterly every year.
On a recent Sunday, the 46-year-old dad briefly perused the selection at a home improvement store in Irvine, Calif., and put a $3.99 air filter in his shopping cart.
Religiously replacing the air filter is good for his family's general health, Schwartz said, but especially crucial to their 18-year-old's life.
"My son has lung disease," Schwartz said. "He was born with early emphysema."
The lungs of people with emphysema are less elastic and cannot fully expand and contract. This can make breathing difficult and inefficient. The air filters remove potentially harmful dust and particles.
The Schwartzes have been keeping the air in their home as clean as possible since their son was an infant.
"We keep mold, mildew and dust away," he said. "And the house is clean and immaculate.
"We don't want to know what could happen to him if he regularly breathed polluted air at home."
Although households such as the Schwartzes' are highly aware of the effect of indoor air pollution, most of us don't think about it because we cannot see the pollution, and sometimes, we can't smell it, the Lung Association's Cook said.
One way to tell when indoor air pollution might be the culprit: "You should be suspicious if more than one person in the home is having trouble breathing, has headaches, nausea and other reactions, or is getting sick a lot," allergist Gillman said. Especially "if those symptoms go away or if they feel better when they are away from home."
Narrowing the suspects to a small group and identifying the exact cause of health problems can be simple, or it can be complicated and time-consuming. Sometimes it may involve a process of elimination. If you or a member of your household experiences headaches, wheezing and irritated eyes and nose after turning up the heat in the room, the air filter may need to be replaced.
Among the indoor air pollution culprits:
- Heating systems and appliances that use gas or wood, for example, can produce carbon monoxide and nitrogen dioxide, both odorless and colorless. When inhaled, carbon monoxide can cause fatigue, headaches and nausea. If there's enough of it, it's deadly.
- Nitrogen dioxide can irritate the eyes, nose and throat and cause shortness of breath in the short term, according to a Lung Association report. Exposure to this gas over time can cause chronic bronchitis.