Which air purifiers are best? It's good to have choices, but not when you're unable to choose confidently. Comparing air purifiers for the home is confusing for many consumers. The bewildering claims made for each type may make it difficult to focus on the best air cleaner for your needs. If you're already familiar with the secret to top performing home air cleaners then you're ready to use that standard to rate each type of air cleaner. More importantly, you're ready to completely reject poor performers. Only HEPA air filters meet a verifiable performance standard. HEPA filters remove 99.97% of 0.3 micron particles, slightly smaller than tuberculosis bacteria at 0.4 micron. One misconception is that HEPA filters perform less well with smaller particles. In reality, HEPA efficiency is higher with smaller particle sizes. An effect called Brownian diffusion helps trap particles smaller than 0.3 micron in the HEPA filter, enabling it to capture bacteria and viruses.

Because of this incredible efficiency the Hong Kong Hospital Authority chose HEPA air cleaners like the IQAIR HealthPro at right to control the spread of the SARS virus. HEPA filters may last two to five years. Thus, your actual cost for exceptionally clean air may be quite low in comparison to air cleaners that require filter replacement every few months. Reject cheap air cleaners A mark of cheap air purifiers, HEPA type filter media may provide no performance indications or specify a standard clearly less than true HEPA. These air cleaners will not give you significant air quality improvement.Because total system efficiency is often no greater than 50%. The Holmes air purifier at left claims a filter efficiency of 99% at 2 micron. This is much larger than the most harmful fine and ultra fine particles. Filters like these may be completely unable to collect the sub-micron to 2.5 micron particles that most seriously affect your health. Even larger particles up to 10 microns, like pollen, may not be removed effectively due to filter bypassing common in cheap air cleaners.

Short filter life is also common. The greatest scam on the market is to sell cheap air cleaners and bilk customers later with costly filter replacements. Reject ionic air cleaners Ionic air purifiers use electric charges to remove allergens and irritants. They have no effect on gases and odors. Particle collection efficiency tends to be no greater than 80%. Studies show efficiency dwindles to as little as 20% in as few as three days as collector plates load with particles. Regular cleaning is a must for continued performance, yet many owners complain it is difficult cleaning collector plates. These models are praised for being silent. This is a marketing ploy designed to present as an advantage the fact that they move little air. Ionic air cleaners also produce ozone which is lung damaging and elevates sensitivity to allergens and irritants. This is the last thing anyone with respiratory problems should be exposed to. Reject air ionizer purifiers

Ion generators, or air ionizer purifiers, release charged ions into the air that attach to particles, statically charging them.heaven fresh hf200 ionic air purifier reviews There is no method of capturing these charged pollutants.therapure uv germicidal hepa air purifier Instead, they stick to surfaces such as walls and furniture or combine with other particles and settle on room surfaces.heaven fresh hf 100 silent ionic air purifier & air ionizer This produces the common problem known as "black wall effect" buyers of these units complain about. The most significant problem with air ionizers is the health threat posed by the "black wall effect" taking place in your lungs.

Studies have shown electrically charging very fine particles results in their higher deposition rate in the lungs compared to uncharged particles. So using ion generators may actually increase the dose of particles to the lungs, making your situation worse than if you were using nothing at all. Proponents of ozone generators claim ozone oxidizes pollutants, reducing them to water and carbon dioxide. In the real world such textbook reactions rarely happen. Instead, numerous byproducts are created. These byproducts can be more dangerous than the original pollutants. Ozone cannot distinguish what is and is not a pollutant. It reacts with almost anything it contacts, degrading materials and creating additional pollutants. Supporters claim ozone kills bacteria but deny it kills cells in your airway. They reject all scientific evidence and warnings that ozone is harmful. Sellers of ozone machines are perpetrating a fraud. They get away with it in the US because no federal agency regulates these products.

On the state level, at least California has banned their sale. An ozone generator is ineffective and exposes you to danger. Is UV light worth the cost? UV air purifiers create ultraviolet light that may destroy biological pollutants like viruses, bacteria, and molds. UV air cleaners have no effect on gases or particles. UV germicidal irradiation should not be used to replace filtration. Destruction of some viruses and most mold and bacterial spores usually requires much higher UV exposures than home ultraviolet air cleaners provide. Because HEPA filtration captures most biological pollutants, adding UV light steriliztion offers minimal benefit. Because mold spores can cause allergic reactions whether dead or alive, UV sterilizers or sanitizers by themselves will not help your allergies or asthma. PCO is of limited benefit Photocatalytic air purifiers are promoted to destroy gases and odors. They have no effect on particulates despite the fact that some marketers would have you believe this.

Titanium dioxide (TiO2) is used as a catalyst in the presence of UV light to cause a chemical reaction between volatile organic compounds (VOCs) and water molecules in the air. Ideally this reaction reduces gases and odors to water vapor and carbon dioxide. Unfortunately, textbook reactions are not always the result. Incomplete destruction of VOCs results in creating additional pollutants that may be more irritating and potentially toxic than the original compounds. Activated carbon for gases and odors Gas phase filters remove gases and odors and are often added to HEPA filtration to enhance air cleaning. The most effective gas filtration is by activated carbon. It removes up to 60% of its own weight in chemicals. A deep bed of activated carbon is best. That is why the best home air purifiers include many pounds of activated carbon. Thin activated carbon pads are practically worthless. They neither have sufficient activated carbon to be effective nor do they supply the dwell time needed to remove pollutants.