| There seem to be as many ways to purify air as | | | | precipitator plate and reuse it. A similar stunt on a |
| there are contaminants to purify out of it. Herein, | | | | larger scale is how a coal-burning power-plant |
| a peek under the hood at the rather complex | | | | scrubs some of the ash out of the smoke it |
| business of keeping microscopic junk out of your | | | | produces. |
| lungs: | | | | Ionizers: Ionizers use static electricity in a different |
| HEPA and ULPA filters: There seems to be two | | | | way; they make the pollutant particles stick to |
| definitions for the acronym HEPA; either "high | | | | each other. This will make a large particle out of |
| efficiency particulate air,", or "high efficiency | | | | many little particles, which then are easier for a |
| particulate absorbing." ULPA means "Ultra Low | | | | filter to trap. Ionization is rumored to have a |
| Particulate Air". Both kinds attempt to strain as | | | | bunch of fringe benefits, such as improving your |
| many foreign particles from the air as they can | | | | mood, helping reduce depression from Seasonal |
| and still let air through. ULPAs are tighter filters | | | | Affective Disorder, and alleviating the symptoms |
| than HEPAs, though only by a few percents. | | | | of asthma - but there is some debate as to |
| Electrostatic Filters: Work the same way the | | | | which of these effects are real. Certainly, I notice |
| static on your clothes do, only they use an | | | | that I feel cheerful just after a thunderstorm, and |
| electric charge on the filter to draw particles to | | | | I'm told that's because lightening puts more ions in |
| the filter. Turn the electricity off, the filtered | | | | the air, so the air always feels cleaner afterwards. |
| particles drop, usually into a disposal receptacle. | | | | Ozone Air Cleaners: In a radical departure from |
| You only need to look at how dust particles tend | | | | previous methods, these purifiers are not content |
| to stick to your monitor's glass surface (it's | | | | to sit and wait for the pollutants to come to |
| generating static electricity, too) to see an | | | | them. Instead, they release small amounts of |
| example in action. Clever, no? | | | | ozone, which then go out and find the pollutants |
| Electrostatic Precipitators: Not just a | | | | and neutralize them. |
| tongue-twister, but a similar concept as the filter; | | | | Ultraviolet: These use radiation from ultraviolet |
| here we're using two opposite charges to attract | | | | light bulbs to kill biological organisms. From germs |
| airborne particles to a plate or grid wire. This is | | | | to funguses, these purifiers are like a "bug zapper" |
| how some of the purifiers that don't need a filter | | | | for microscopic bugs! Frequently seen in hospitals. |
| to change work; you just wash off the | | | | |