As with most products, a proper review of personal air purifiers requires some knowledge of air purifiers. To do this you would need a general understanding of personal air purifiers. A review of the workings of these devices shows that air filters utilize sieves which filter particles from the circulating air. As the air flows into the air purifier the sieve traps the particles. The finer the sieve, the smaller the particles it can catch. The accepted limit for air filters has been set by High Efficiency Particulate Air filters, or HEPA filters, which trap on average 99.97% of airborne particles larger than 0.3 microns. A micron is a standard unit of measure for air particles. The smallest particle you can see is 10 microns.
HEPA filters remove allergens such as the following:
- Pet dander
The more times air passes through a filter, the cleaner the air becomes.
Another type of method used by air purifiers is electrical attraction. There are three types of air cleaners which use this technology.
- Electret filters
- Negative Ion Generators
Electrostatic purifiers, or electronic purifiers, draw air particles in by a fan and charge them with a series of high voltage wires. Plates then carry an opposite electrical charge which attract contaminants as they pass by the plates. A review of personal electronic air purifiers show these to be perfect for people who don’t want the worry about constant replacements of HEPA filters.
A review of these personal air purifiers shows a use of synthetic fibers used to create static charges to attract particles. These filters come in a variety of types including the following:
The type of filter needed will determine how often you will need to replace them.
Some types of electrostatic filters combine HEPA technology with the electrostatic method to create a more effective air filter such as the Blueair purifier.
Negative Ion Generators
These type of purifiers use tiny charged wires or needles to create gas molecules which contain negative ions that stick to airborne particles and collect inside the filter. Reviews of some personal air purifiers of this type show that many of these ions end up returning to the air and attach to furnishings and other surfaces.
Ionic purifiers remove only certain types of particles and are mostly not effective against such things as gases, chemicals and odors. Other products have shown to re-circulate the particles that they drew in. This makes then less effective than traditional purifiers using the HEPA type of filtration.
Reviews of these personal air purifiers show that instead of using filters to trap particles, an ozone generator uses high voltage electrical currents to covert oxygen into ozone. This then acts as a oxidant and breaks down the microorganisms in the air. Multiple tests have shown this type of purifier is not very effective for removing indoor allergens.
The main concern with ozone generators is the potential of the following problems:
- Aggravation of allergies and asthma
- Damage to lining in nasal passages
- Can cause coughing, throat irritation, and shortness of breath.
Depending on the need for a personal air purifier, a review of available systems is recommended.