Indoor air pollution is a growing concern for many people, especially those with respiratory problems. To address this issue, researchers have conducted studies to determine the effectiveness of air filters in controlling indoor air pollution. The results of these studies have been promising, showing that air filters can reduce fine particles by up to 55 percent and contamination from outside particles entering inside by up to 23 percent. In addition, air filters have been associated with a 9.4% increase in the reactive hyperemia index and a 32.6% decrease in C-reactive protein. The most effective approach to solving indoor air pollution problems is usually to eliminate or reduce indoor sources of pollution.
Ventilation helps remove contaminants from indoor air, but not as effectively as source reduction. Ozone generating air purifiers are devices that purposely create ozone to clean the air through chemical interactions that alter the compounds of pollutants, but this is also the mechanism by which ozone exerts harmful health effects. In addition, ozone is generally ineffective in controlling indoor air pollution at lower concentrations. In other words, if the ozone concentration in the room is high enough to be effective in cleaning the air, it is also high enough to create an inhalation hazard for people in the room. For these reasons, Environmental Health & Safety (EH&S) does not recommend the use of electronic air purifiers or ozone generators under any circumstances.
For the sake of health safety, air purifiers with mechanical filters (such as HEPA) should be used instead. Heat Recovery Ventilators (HRVs) and Energy Recovery Ventilators (ERVs) help save money on the electricity costs associated with a ventilation system by using energy from exhaust air to heat or cool incoming fresh air. Some filters are reusable and washable, but require meticulous maintenance, so they are not normally found in the most effective air purifiers. New data also reveal a stronger link between indoor and outdoor exposure to air pollution and cardiovascular diseases, such as strokes and ischemic heart disease, as well as between air pollution and cancer. Data from 30 participants enrolled in the study showed that when HEPA filters were used during the winter investment months, only five percent of PM2.5 in outdoor air contributed to indoor air quality, compared to 28 percent when HEPA filters were not in use. An AER of 0.5 air changes per hour is generally suitable for removing moisture and odors from a home that does not have a large source of indoor air pollution. In fact, the Environmental Protection Agency (EPA) warns that the functionality of air purifiers is limited in terms of filtering gases and that you should replace filters frequently for optimal functionality, usually about every three months or more. In air purifiers, the air was first filtered by a coarse-grained pre-filter, followed by a Rota filter, in which small dust particles were captured by high-speed rotation.
HEPA filters are 99.97% efficient at removing particles smaller than 0.3 microns, require right-sized fans and center ducts, and are now increasingly available for use in domestic central forced air systems. While working, air purifiers draw air from the room they're stationed in, push that air through a filter to trap contaminants, and expel cleaner air. This type of air filter can theoretically remove at least 99.97% of any particles in the air with a size of 0.3 microns (µm), which can include dust, pollen, mold and bacteria. For general indoor air, both air purifiers reduced the concentration of PM10 so that the resulting concentration was below the prescribed limit of the USEPA and the National Ambient Air Quality Standards (NAAQS), but remained above the limits prescribed by WHO. In fact, air purifiers can neutralize some of the threat posed by air pollution and indoor activities. In any case, by reducing the amount of solid particles in your home's air, purifiers work to increase the air quality of a room, even if they may need help eradicating threats altogether. Air cleaning systems or units designed for use as part of a central heating and air system must be designed and installed by an experienced and licensed mechanical contractor or heating and ventilation contractor. Studies show that using an ozone generator can produce harmful levels of ozone in a home, more than three times California's outdoor air quality standard of 90 parts per million ozone, and at levels high enough to trigger a stage I smog alert if measured outdoors.
