Purchasing an air purifier can be confusing, and you do get an awful lot of information thrown at you when you visit the different manufacturing websites, don’t you? How can you tell what, and why do we need air filters anyway? And how do air purifiers work? Is the air really that bad? Haven’t We been breathing the same air for thousands of years? Yes and no. First of all, we are been breathing the same air for thousands of years, but we live in a symbiotic relationship with the plants around us… that is, we rely on each other to survive.
We breathe oxygen to live, and give off carbon dioxide. Plants exchange carbon dioxide for oxygen, effectively exchanging the air in a healthy relationship with us. This makes plants the first primitive air purifier on earth, and explains why scientists are so concerned about the ecological balance on earth and the need for the survival of rain forests and plants: they ensure our own survival as well by preserving oxygen in our atmosphere.
Nature cleans the air in other ways as well: ozone (positively charged oxygen molecules) is generated by waterfalls and thunderstorms. Ozone also cleans impurities and particulates from the air naturally.Â
The Industrial Revolution and Air QualityÂ
The industrial revolution made great strides in everything but air quality.
In fact, pollution such as emissions from automobiles, smog, and pollution from everyday chemicals like cleaning fluids, carpeting, and paints enter the air every day. In industrial settings, air purifiers clean the air before it is released into the atmosphere in order to meet government requirements.
Today, homes are also more energy-efficient and cost-effective, but to get there they have become much more closed in. When they are this sealed up, indoor pollutants are shut in so that today’s homes are actually two to five times more polluted than outdoor levels! Obviously, air purifiers are essential to improving indoor air quality to combat the effects of this stale, recirculated air.
Beginning in the 1980s, medical practitioners began to take note of the direct link between poor indoor air quality and the increased incidence of conditions such as asthma, allergies, and recurring colds, and upper respiratory infections. The development of a variety of improved, scaled-down air filtration systems for in-home use soon emerged. How the Main Types of Air Purifiers Work One of the most commonly used type of air purifier is also one of the first developed and is used in most hospitals and clean rooms.
With such different types and so many products available for us to choose from, how to decide which is best? Let’s take a look at the basic categories of air filtering devices and what each group offers:
HEPA filterÂ
HEPA Filters During the Manhattan Project in the 1940s, the Arthur D. Little firm developed the first HEPA filters in order to filter out very small particles that had become contaminated by nuclear radiation in atomic bomb testing areas. It was during this initial development that the HEPA standards were set at 0.
3 microns, which could effectively capture condensed radioactive iodine. The filters at that time were called absolute filters, and not called HEPA (High-Efficiency Particulate Air) until the filters were marketed in the 1950s. Today these filters are used by hospitals, surgical wards, biopharmaceutical research labs, microcircuitry labs, and the aerospace industry for their exceptional ability to control dust and particulates.
HEPAs remove 99. 97% of particles of 0. 3 microns or larger. For even more intense filtration, there is a ULPA, or Ultra-HEPA filter, which filters out 99. 99% of contaminants pass through the filter. Obviously, something has to draw the air through the filter, and with HEPA filters this is a motorized fan.
This can make them noisy, which makes them an annoyance to some people. A HEPA filter will need to be replaced every 12-18 months, depending upon how it is used and the interior environment of your home. For instance, if you have pets, especially cats or dogs that shed a lot, you may need to change it more frequently because of the dander. If there are smokers in the house you will also need to change your air filter more frequently to ensure proper filtration.
However, for overall performance, nothing filters out or eliminates more particulates than a HEPA filter, so it is a matter of balancing cost, sound preference, and convenience against your relative needs when choosing the right model of air cleaner for your home. These filters are so good at cleaning the air that they are often considered the most efficient of all filtration units. But don’t rush out to buy one yet-there are a few important factors to consider. HEPA filters need to be replaced frequently, which makes sense when you consider that they function by trapping contaminants. Depending on the cost of filters and the frequency with which you need to change your particular model, this can be an expensive choice. Moreover, HEPA filters are good at cleaning the air within small spaces, but they are not a home-wide solution. Of course, you could place a filter in each room, but this may not be practical.
Still, if you want a great bang for your buck, HEPA filters are a terrific choice and very, very effective. Just keep the above considerations in mind when choosing one (or several) portable filter units for your home.
Ozone Air PurifiersÂ
Ozone is created in nature by everything from waterfalls to thunderstorms and is responsible for that fresh, clean smell after heavy rain or storm has passed.
It’s nature’s way of cleaning the air. Ozone air purifiers essentially do the same thing indoors by artificially mimicking the natural process that creates ozone. Ozone molecules exist in the air all around us, and will react with any particles they come into contact with, but are very unstable and tend to exist in small quantities for short periods of time.
Ozone air purifiers work by using electricity to generate more ozone molecules, which have one more oxygen (O3) than we normally have in the air (O2) around us. Since ozone is highly unstable, one of the oxygen atoms is always inclined to break away and find another molecule to bond to. This process causes a chemical reaction that destroys odors and germs in the air and then converts what is left of the molecules into harmless oxygen and CO2.
There is some confusion between ozone air cleaners and ionic air cleaners, but there are some differences. With an ozone air purifier, the ozone that is released into the air will be unstable and cause a reaction that will alter and destroy certain germs, viruses, bacteria, and molds.
It does not, however, have a collection plate where dirt or grime collects.Â
Pleated Filters
These may also be called “media” filters. They are similar to HEPA filters but are pleated, or folded, with the result that they are substantially less effective. A pleated filter will trap as little as half the particles as a HEPA filter, but it will do well with containing larger particles. So, for example, if your main problem is dust, this may be a good choice for you.
Ionic Air CleanersÂ
An ionic air cleaner also uses electrical charges to alter oxygen atoms in the air, like an ozone air cleaner. But unlike an ozone cleaner, an ionic air cleaner will rid the air your breathe of dust and pollen as well. Ionic air cleaners negatively charge the air particles in a room, which will cause a magnetic attraction to occur.
The positively charged particles in the air, such as dust, pollen, and pet dander, will naturally be attracted to these, and they willing to each other, creating a sort of magnetic bond. Particles that form into bonds like this become too heavy to remain suspended in the air and fall to the ground, where you will no longer be able to breathe them into your system.
Vacuuming and regular dusting can get rid of these particles. In today’s ionic cleaners, there are also fans that move the room air over negatively charged metal collection plates that the positively charged particulates will stick to. These can be regularly cleaned by simply wiping them with a soft cloth.Â
Electrostatic PrecipitatorsÂ
Whereas HEPA filters physically block and remove pollutants, requiring the replacement of filters, electrostatic or electronic cleaners work in a slightly different way. These units contain electronically charged plates that impart an ionic charge to floating air particles, causing them to be attracted to the plates (remember high school science class?) and forced through what is known as foam pre-filter.
The original electrostatic precipitators were huge monsters used to control pollution emissions from industrial plants.
The waste by-products of a plant were sent through large chambers that were charged by electrodes that acted as enormous collection plates to attract the oppositely charged waste products (such as dust, lead, sulfur, fly ash, and other hazardous chemicals) from the materials passing through, filtering out all harmful materials.
Periodically, the precipitators would be applied so that these materials could be dumped from the chambers into disposal units. Home electrostatic precipitators also work on the theory of using a negative charge and a positive charge to collect and retain particulates, however, the charge takes place within the air purifier itself rather than in huge chambers, and the dust and particulates are captured on metal filters that can be removed and cleaned or replaced, getting rid of the need for a separate collection chamber for the particulates.
Electrostatic FiltersÂ
With electrostatic filters, a small static charge is created that attracts airborne particles as they go through a filter, capturing even those particulates which are too small to be captured by the relatively loose weave of the filter itself.
Because of the looser weave, the airflow in an electrostatic filter is very good, but the filtration is very effective because of the electrostatic charge. These filters do have to be carefully maintained and cleaned at least monthly and should be replaced every year for peak effectiveness. As the filters do become dirtier, the airflow will become less efficient. Finally, there are systems that combine two or more types of air purification systems.
You won’t have replaced the plates contained in these units, but you will have to wash them periodically to clean them of debris and buildup. If you don’t, you run the risk of the particles getting re-re-released into the air. A clean and well-maintained unit will keep down the amount of dust, mold, and bacteria in your home environment.
While these are usually more expensive, they can be worth the price if you are looking for the best possible combination of features. For instance, an air purifier that will kill viruses and bacteria like an ozone air purifier, but will also effectively filter out dust and dander with a HEPA filter.
Cleaners with Activated Carbon
Filter and electrostatic cleaners grab offending particles from the air, but a different technology is needed in order to rid your living space of odors and invisible chemical contaminants. That’s where carbon comes into the picture-some air cleaners are sold with mats of activated carbon, which pulls these teeny molecules out of the air to keep it squeaky clean. Note that many electronic filters do contain carbon filters.
Charcoal Filters
A charcoal filter, or any air cleaning device that contains a charcoal filter, can be very useful if you battle unwanted odors in your home environment. This is because charcoal is a porous substance with a great capacity for trapping gases with offensive smells. Charcoal, when used in a filter, may be treated with chemicals in order to enhance its ability to eliminate odors from the air.
Hybrid Filters
Simply put, hybrid filters are filters that are combinations of multiple types of air filters. For example, a popular type of hybrid filter involves both an electronic charge, as described above, as well as a pleated fabric to capture and collect particles in the air. This can be a good all-around solution to your clean air concerns, but just be sure to keep the filter itself clean, otherwise, it won’t function properly.
In making your decision, choose based on the amount of space you wish to treat, as well as your largest areas of concern. For example, if you smoke or live in a place where the air has been exposed to smoke, you may wish to use a filter that removes odor as well as particles. If dust is your main concern, then a pleated filter may do the job for you. Whatever you choose, you will be well on the way to a healthier and happier home environment!For the shocking truth of how filthy indoor air can get, please visit our indoor pollution and home air filter purifier site.
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