Companies that sell air purifiers advertise them as devices that can remove pollutants or contaminants from the air inside homes. These include internal pollutants, such as those emitted from cleaning products and plastics, as well as external pollutants, such as emissions from cars and buildings that seep in through doors and windows. Although using an air purifier can have health benefits, especially if you have asthma or another respiratory condition, there are also disadvantages to air purifiers.
Some types of air purifiers -- specifically ozone generators, electrostatic precipitators and ionizers -- emit ozone into homes. Ozone is a colorless, toxic and unstable gas that has three oxygen atoms in each one of its molecules. The gas occurs naturally in the upper atmosphere, but it is also a common component of man-made smog. Ozone generating air purifiers deliberately emit ozone gas as a strategy for eliminating bacteria and chemicals in the air. In contrast, some electrostatic precipitators and ionizers emit ozone unintentionally as a byproduct of their function. These latter types of purifiers electrically charge contaminants in the air to remove them. The charging process can result in ozone release. The California Environmental Protection Agency states that ozone exposure is harmful to cells in the lungs and airways. Side effects of exposure to the gas can include shortness of breath, coughing and chest tightness. Patients with asthma or other preexisting health conditions may experience intensified symptoms of those conditions as a result of ozone exposure.
Apart from potentially worsening the quality of the air in your home, air purifiers can also under-perform, and not provide all of the purifying effects that manufacturers claim. As AllergyEscape.com notes, there are several types of contaminants that can impact air quality, but unfortunately, most air purifiers are only effective against two or three. For example, while purifiers that use activated carbon air filters can remove odors, chemicals and gases (including smoke), they are ineffective against microorganisms and allergens. Oppositely, while HEPA (high efficiency particle air) filtration purifiers can capture allergens, they are ineffective against odors, chemicals and gases, including smoke.
Many air purifiers rely on the use of disposable, replaceable filters, which means you need to spend anywhere between $30 and $200 each year on new filters. If you do not change a purifier's filter periodically, the filter does not function optimally. For purifier models that employ re-usable containers or plates to collect contaminants, you must periodically clean out these components. While maintaining these latter types of purifiers is less expensive, it is also more labor intensive.