Air Filters: They Can Do More Harm Than Good


April 4, 2006 — -- Desperate affairs require desperate remedies. And no one is more desperate than allergy sufferers who endure the grip that allergies hold on their lives.

Remedies for allergies range from prescription medication to homeopathic treatments like grape seed extract, licorice root and massive doses of vitamin C. Few, if any, of these alternative treatments have proved effective, and medication often comes with unwelcome side effects.

Some people with allergies, however, swear by air cleaners. Manufacturers of these popular products claim that by removing or neutralizing animal dander, mold, pollen or other allergens, their air cleaner will help to eliminate the misery of allergies.

But health experts worry that this cure may not help everyone, especially if the unit uses ozone to clear the air. In some cases, according to Jeffrey Asher, vice president and technical director at Consumers Union, which publishes Consumer Reports, "The air cleaner turns on you."

"This is one of the products most people don't need to buy," Asher said of air cleaners. "The exception would be a person who has a problem with allergens."

Asher added that people who live with a smoker might also enjoy some relief by using an air cleaner.

"A good air cleaner will remove smoke from the air," he said.

Dr. Norman Edelman, chief medical officer for the American Lung Association, agreed that air cleaners may be effective in some cases.

"If you look at the engineering data, they are effective at removing particles from the air. There's some evidence that the good ones reduce the symptoms of allergies."

Most air cleaners operate with a filter, such as a mesh screen, a high-efficiency particulate air filter or an electrostatic system that collects particles that cling to surfaces within the cleaner.

But some air cleaners operate by generating ozone. Manufacturers of these products claim that the ozone works by attaching an oxygen molecule to other particles in the air, which then neutralizes or eliminates the particle's harmful or allergic properties.

Ozone, however, is recognized by the Environmental Protection Agency as a pollutant that can produce serious adverse health effects. According to one EPA statement, "Relatively low amounts [of ozone] can cause chest pain, coughing, shortness of breath and throat irritation. Ozone may also worsen chronic respiratory diseases, such as asthma, and compromise the ability of the body to fight respiratory infections."

Numerous medical experts have also weighed in, noting that adding ozone to the air might be the last thing an asthma or allergy sufferer would want to do.

"For sensitive people who already are experiencing some respiratory distress, over a period of time the ozone generated by these units could cause them harm," said Asher. "The people who need them [air cleaners] the most, many times buy an air cleaner that can harm them.

"When I listen to infomercials these days, I hear them talk about the fresh air smell these units generate. That smell is actually ozone," Asher added.

"The American Lung Association position is that ozone is an irritant," said Edelman. "We don't recommend any air filter that generates ozone."

Before investing in any treatment or air-cleaning product, most allergy experts recommend attacking the allergen, whether that involves rigorous cleaning and disinfecting or removing the source completely

That may be easier said than done, however: "If you like Fluffy the cat, you're not going to get rid of Fluffy," said Asher.

Controlling allergens may be as simple as opening a window.

"Many people should try to ventilate the house," Asher added.

Homes are better sealed these days, thus keeping many outdoor allergens like tree pollen outside, but that same tight seal can trap air inside, along with solvents, cooking odors, smoke, pet dander and other allergens.

"In truth, the air can be cleaner outside than inside," Asher said, noting that in urban areas that might not always be the case.

For people who have tried these steps and are still considering an air cleaner to control allergies, Asher recommends starting small.

"I would probably start with a room unit in the bedroom," he said. "See if your allergy does abate. Then consider a whole house unit."

ABC News Live

ABC News Live

24/7 coverage of breaking news and live events