Research has shown that the air we breathe indoors can be as much as 100 times more polluted than the air outside! To dramatically reduce indoor pollution, we need to continuously clean the air effectively.
We carried previous articles on: Air indoors more polluted than outdoors and Air pollution kills!
The US Environmental Protection Agency (EPA) recommends using air purifiers to filter out allergens, odours, and other impurities. But with the wide range of air purifiers available on the market, figuring out which model is best for you may prove to be a challenge.
Let's take a look at some common types of air purifiers/cleaners in the market.
Negative ion air purifiers use chemical injections to clean the air. An ion is a natural particle with either a positive or negative charge. They get charged by either gaining or losing an electron. Negative ions magnetically attract airborne particles such as pollen and dust until the newly-formed particle is too heavy to remain in the air. This causes the particle to drop and attach itself to another solid item in the room, such as a window or wall.
The negative ion simply takes the airborne particles out of the air and transfers them to solid items in the room instead of completely eliminating them; meaning they could become loose and re-circulate back into the air. Ion generators also release ozone as a by-product. These type of air purifiers, unfortunately, dominate the retail shelf space and have strong advertising support.
Ozone air purifiers, meanwhile, intentionally produce ozone (Oâ). Manufacturers of these devices claim that the ozone deodorises and disinfects the air. Many also claim other health benefits from the presence of ozone. However, there is strong evidence that ozone does not accomplish air purification. Ozone is toxic, a lung irritant, and also unstable -- it reacts readily with other chemicals that may be in the air, forming new compounds that can be even more dangerous! Ozone also oxidises metals and causes corrosion.
The same process that is used with ozone and ion generators is used with electrostatic precipitators. The primary difference is that electrostatic precipitators actually filter impurities out of the air too. The impurities are collected on plates that can be washed, so there's no need to buy replacement filters.
The most common air purifiers are those with filters. These machines pull air inside and pass it through a series of fabric filters and/or absorbent carbon filters using the power of a circulating fan. As air moves through each filter, airborne particles and pollutants are filtered out and locked away in the filter. Clean air is then circulated back.
Filters are capable of catching particles even smaller than the smallest gaps in the filter material. Air filters can be expensive, and you have to replace them to keep them functioning efficiently. Some filters are washable though.
The best air filters are arguably those with HEPA-level filtration. HEPA is an acronym for "High Efficiency Particulate Air" or "High Efficiency Particulate Arrestance". A HEPA filter is one manufactured, tested, certified, and labelled in accordance with current HEPA filter standards. There are several sub-classes within the HEPA classification. The minimum HEPA category requires the filter to capture 99.97% of the 0.3-micron (0.000012-inch) particles in the air passing through it. The filter can consist of any material as long as it meets this standard.
HEPA air purifiers are the most effective at trapping airborne particles; however they do not remove odours, chemicals or gases. Therefore, most HEPA air purifiers have some level of activated carbon based material to absorb odours and chemicals not caught by the HEPA filter.
If you suffer from allergies or asthma, a HEPA air purifier is the best choice. HEPA filters have significantly better particle removal performance compared with ionic and electronic air cleaners. In addition, HEPA air filters often improve performance over time whereas the filterless technologies (ionic, electrostatic) see a decrease in performance over time as the electronic plates become dirty.
Then there are filters that combine the best in electrostatic and mechanical filtration technologies. Blueair , for example, has developed a unique patented technology called HEPASilent®, which combines advanced filter media and an encapsulated particle charging chamber, delivering results far superior than either mechanical or electrostatic technology alone. And its filters use less energy and are quieter to boot (HEPA filters tend to be rather noisy). Even on the lowest setting, its air purifiers capture 99.97% of airborne particles down to 0.1 micron in size. This has made them achieve top scores in leading consumer tests all around the world.
To help consumers worldwide determine how well an air cleaner reduces pollutants such as tobacco smoke, dust and pollen, the US Association of Home Appliance Manufacturers (AHAM) has put in place the Clean Air Delivery Rate (CADR) measurement. Room air cleaners that are AHAM-certified have been certified and verified by an independent laboratory, assuring consumers that the product will perform according to the manufacturer’s product claims for suggested room size and the reduction of three common household particulates: tobacco smoke, dust and pollen - the AHAM Label found on the packaging of the air cleaner lists the CADR numbers for the three pollutants.
The CADR indicates the volume of filtered air delivered by an air cleaner. The higher the numbers, the faster the unit filters the air, with maximums of 450 for pollen and smoke, and 400 for dust. AHAM recommends using an air cleaner with a CADR number at least two-thirds the area of the room.
Air volume is often described as air changes per hour (ACH), the number of times the total volume of air in the room is processed by the unit within an hour. The more air changes per hour an air purifier produces, the cleaner your air. Allergy and asthma sufferers, and those wanting to create the cleanest indoor air possible, should look for air purifiers that can produce at least 4 ACH. Some manufacturers substitute ACH rates for CADR results, but they are not equivalent. CADR numbers give a much more precise report of an air filter's performance.
Given air pollution's impact on our health, getting an efficient air purifier would be a sound investment, no?
This article is brought to you by Blueair www.blueair.com/my
