How Air Cleaners And Purifiers Can Help Your Asthma

When coupled with source control, aggressive ventilation is probably all that many asthmatics will ever need. If, however, you have seasonal allergic asthma or are sensitive to outdoor air pollution, there may be irritants in the "good" outdoor air that can trigger your asthma. This is where air cleaners and purifiers can be beneficial. Air cleaners come in all shapes and sizes, but there are three basic types: mechanical air filters, electronic air filters, and ionizers. Likewise, air cleaners perform three basic functions: filtering particulate matter, removing gaseous pollution, and circulating air. Air cleaning is a complicated subject, so let's first look at filtering particulate pollution.

 

 

It is important to remove both large particles that cause allergic reactions and small respirable particles that can find their way deep inside the lung and cause damage. Particle filters range from the boxed filter on your furnace to high-tech, asthma-friendly High Energy Particulate Air (HEPA) filters, which trap almost all airborne contaminants.

 

 

Mechanical filters used to be packed with fiberglass or some other fine fiber that was treated with a "sticky" substance to help trap particles and boost efficiency. The filter would be either flat or pleated, with the pleats dramatically increasing surface area. As filtering technology improved, these simple fiber filters were given an electrostatic charge that could trap even smaller airborne particles. These basic fiber-based mechanical filters are still made and are commonly found at the local hardware store. In fact, if you look at your furnace or air-conditioning intake vent, you'll probably see one of these mechanical filters. Despite the technological innovations, fiber-based filters still only trap the largest particles; they simply don't cut it when it comes to asthma.

 

Filter technology has fortunately continued to mature, and there are filters specially designed for people with allergies and asthma. To be designated a HEPA filter, these state-of-the-art air filters must have a minimum collection efficiency of 99.97 percent. If you have allergic asthma or suspect your lungs are bothered by particulate pollution, a HEPA filter can be your best friend.

 

 

HEPA filters represent the cutting-edge in mechanical air filtration and will probably remain an industry standard for years to come. However, "electronic precipitators" or electronic air cleaners are an emerging technological innovation. Using less electricity and operating noiselessly, electronic precipitators have found a place in bedrooms across America. Electronic air cleaners employ a charged filter to collect particles. Many manufacturers add ionizers to their units that place a charge on airborne particles before they enter the system, thereby making these particles more "sticky" and improving collection efficacy. Electronic air cleaners can be used alone or combined with a HEPA filter. A potential drawback to electronic air cleaners is that they can lose efficiency if not properly maintained. Another problem with electronic precipitators is that some models produce ozone, a gas that is especially troublesome to some asthmatics.

 

Though HEPA filters have an established track record, you may want to consider the new HEPA/electronic precipitator hybrids, while avoiding units that produce ozone. I suspect that as technology improves, electronic precipitators may emerge as a superior air-purifying product.

 

 

Ionizers place an electric charge on particulate pollutants so they will stick to an oppositely charged surface. This means that unless the ionizer is combined with a collection filter, the charged particles will end up sticking to anything: floors, drapes, furniture, and even people. In my opinion, ionizers don't clean the air, they just stick pollution elsewhere. Unless it comes with a collection device, don't buy an ionizer.

 

 

Some manufacturers add ozone generators to their air cleaners, claiming that ozone "freshens" and "cleans" the air. Ozone, however, is a reactive oxygen species that asthmatics clearly should avoid. According to the EPA, ozone can be unhealthy with little potential to remove indoor air contaminants. Ozone generators are dangerous to your health and simply don't work.

 

 

My advice on scented "air fresheners" is to throw them out. Scented air fresheners only mask one odor with another and do absolutely nothing to improve air quality. Many asthmatics, including myself, are driven nuts by the smell of air fresheners.

 

 

Particles are only part of the air-pollution problem. Quality air purifiers remove both particulate matter and gaseous and chemical pollution, a process called "sorption." Without question, asthmatics need air cleaners that perform both functions well. Most sorption systems use a sorbent, such as activated carbon, to suck up chemical and gas fumes. Like mechanical air filters, sorption systems receive an efficiency rating based on the amount of chemical and/or gas absorbed. Sorbents do not last forever and, like particulate air filters, the more material they absorb, the less efficient they become, so you have to periodically replace the sorbent.

 

Activated carbon is a common sorbent that works well even in humid environments. Carbon is also an excellent odor absorber; however, just because you can't smell anything doesn't mean the toxin is gone. Carbon filters may remove the smell, but the toxin can still be present at imperceptible levels and thereby impact your health. Carbon filters also tend to get saturated quickly, necessitating frequent replacement. Filter saturation not only reduces efficiency but also may cause the filter to reemit chemicals into the environment. Once again, the best way to deal with noxious fumes is source control; if you remove the source of the irritant, you won't have to worry about absorbing it.

 

If source control is impractical or not possible, activated carbon is your best, albeit imperfect, choice. Activated carbon is one of several sorbents, some of which are designed for specific chemicals like formaldehyde. As a rule, specialized sorbents outperform activated carbon; however, unless you have identified a specific chemical substance to which you are sensitive, most asthmatics do well using an activated carbon filter. No matter what type of filter you use, always follow the manufacturer's recommendations regarding replacement.