With all we know about toxins in our household products and their impact on our health and environment, it’s clear that air purifiers and other air cleaning devices are no longer luxury items. However, not all of these devices are created equally so it’s a good idea that you know the basics about the different filters and machines available so you can make the right choice for your household. Air cleaning devices use one or more of several types of cleaning methods including:
- Activated carbon
- HEPA – High-Efficiency Particulate Arresting filters
- Electrostatic filtration
- Negative ion generation
- Ultraviolet light
- Electrolyzed Water Technology
#1 Activated carbon is effective at removing gas molecules and odors. It works by adsorption (particles stick to carbon), and some carbon filters are coated to remove specific substances. The carbon bonds with the particles and odors when the air passes through the filter. This air purifier can catch smaller dust particles than a HEPA filter. “Adsorption” occurs when materials attach through a chemical reaction. A copper-nickel salt combination or zeolite is effective in absorbing formaldehyde, for example. Zeolite is a natural mineral that has the distinct capability of absorbing certain gas molecules. Zeolite is particularly effective in absorbing formaldehyde, ammonia and carbon monoxide. Activated carbon filtration is good for cigarette smoke, gases, odors, mildew, formaldehyde and pesticides.
Potassium permanganate is activated alumina impregnated with potassium. It absorbs gases and destroys them by oxidation. Normally used with activated carbon filters, it is good for formaldehyde, hydrogen sulfide and ethylene.
SAVING GREEN: Total Cost: $25 for the replacement filter
#2 Mechanical filters work by trapping particles. We recommend non-petrochemical true medical grade HEPA (high efficiency particulate arresting) filters, which are rated 99.97 percent efficient in removing particles .3 microns in size or greater (ie: dust, pollen, mold spores). A human hair is about 300 times too large to penetrate a HEPA filter. Developed by the Atomic Energy Commission to remove radioactive dust from industrial exhausts, HEPA filters are paper-like filters made of randomly positioned fibers that create narrow passages with many twists and turns. As the air passes through, particles are trapped, clogging holes and making the grid smaller, which enables the filter to be even more efficient with ongoing use.
SAVING GREEN: Total Cost: $99.00 and up.
#3 Electrostatic filtration attracts particles by creating an electric charge that the particles stick to. Electronically charged plastic panel filters (electrets) can be inserted into your central heating system and are extremely efficient in removing dust particles, pesticides, smoke, bacteria and some viruses, but must be cleaned often and if dust remains the filters can release toxic gases that can be inhaled and cause symptoms. These types of units can produce ozone. If you are going to purchase this type of air purifier, verify that it does not produce ozone.
SAVING GREEN: Total Cost: $30.00 for the filter, $130 and up for the unit.
Get the remainder of the list in our next post: 7 Secrets to Choosing the Best Air Purifier for Your Home – Part II