How to Choose the Right Air Purifier
Everywhere you turn there are air filter options. Very different machines promise allergy relief and health in magazines, on TV and on the Internet. Choosing one is hard. Currently some offer new technologies that are helpful or useless, so lets look at the basics. The first thing to decide on is what "junk" you are trying to remove.
Placement of An Air Purifier
First, many homes have air cleaning systems that have air intake areas. These generally have filters. Since the motors that run these usually come with the home and your AC/Heating system, you do not have to "buy" or "place this" anywhere. However, many people neglect this "air purifier." So start with putting in "good" filters. As a trend, most folks would do well with something that would remove mold spores and gases. That means you would get a filter for particles with a charcoal film for gases and chemicals.
The more the filter filters the slower the airflow. So HEPA is fine as long as the air is not still. Also, mold can grow through a filter; so do not plan on ignoring it for 20 years. (If you wonder if you are getting mold in the home, you might consider sending off your filter to QMS labs for three media testing and speciation of three forms for $215.00.
You would also be amazed at how much charcoal will change as it reacts to gases in a new home. We have had good results with a thin film sheet charcoal that is about 3 mm thick, which sits over the pre-made 12x12 or 12x24 inch inlets for the HVAC system. In Home Depot, some of the smart helpers are not aware that this 6 inch by 12 inch white boxes of charcoal sheets are in the store.
Placement of Portable Machines
Many of these machines come with very impressive room size cleaning numbers. I am biased in two areas. I like air cleaners bigger than the room size, since most people tend to over-rate the cleaning ability of the machine and under-rate the junk coming from 300 sources in their structure.
One reason I like the air purifier on the oversized end is that the ratings for room cleaning are for open rooms, not rooms with desks, sofa's, refrigerators or two bookcases. The air cleaner is not reaching around a computer workstation, a couch against the wall or reaching down the basement. It is fairly amazing that some machines claim to clean multiple rooms with virtually no air movement. I suppose it is magic.
In any event, make sure bedrooms and the main living spaces are covered. And be alert to hot spots with need, e.g., newly painted rooms, areas with painting supplies and chemicals, and high traffic entry areas carrying in mold spores, pollen and dust.
At this point let me address the "zapper" machines. As the co-author on a book about mold and mold biotoxins, I am very concerned with spores that carry chemical toxins being zapped, and having their chemical toxins floating around after the spore is zapped.
The most important rooms to clean are your main family living areas, the kitchen and bedrooms in which you spend at least 7-8 solid hours. Machines often talk of square feet, and for simplicity lets say that is merely width times length. So a 12 x 15 foot room is a large 180 square feet. If you have 20-foot ceilings you should assume you would need some extra power. If they are modest 8-9 foot ceilings, plan on a machine that can do 360-400 square feet. Also, if you set the machine in the slow button do not assume much is being cleaned. So when you leave a room, e.g., the living room at night or you bedroom in the daytime, blast the machines!
This rating is not something I will go into detail on since it is not used universally in the air-cleaning field.
Types of Air Purifiers
HEPA filters have been used for years and fit most home or small office settings. The best home machines I know are IQAir machines. They also offer various amounts of charcoal. We have been pleased with them.
Is Ultra Violet Important?
If you are out in the sun for 5 seconds, you will not get a burn. And if the air you want to purify is only exposed to a filter's UV light for seconds, it will do little to help you.
Yet one that is well engineered can be useful, and consider this one below if you want the killing power of UV for air. I have used UV for water cleaning, and this company has a good reputation for quality, and understands the need to special exposure so that UV will be effective.
So What About Ozone?
Ozone purifiers produce electrical charges that can go through walls. It will purify many environments, but is not a discriminator. It will hurt bacteria, molds, and your lungs. I have been stunned to walk into home of asthma pateints, during house calls, and found the home filled with a mild ozone bleach smell. When inhaled, ozone hurts fragile lung sacs. Some report chest pain, coughing, shortness of breath, headaches, and throat irritation. I have had all of these after 45 minutes in ozone filled room. It can worsen COPD, emphysema and asthma. According to OSHA, ozone is 50x more dangerous than carbon monoxide.
While some groups feel ozone never is useful, I do think it can be helpful to a home. However, lets mention two limitations first. Ideally, you cannot be near them when they are on, because they hurt lung cells just like they hurt molds and bacteria. I do not know how long one needs to allow the ozone to dissipate, but certainly hours. Also, I am not sure if they have any effect on the toxic chemicals carried by some indoor mold spores.
Electrostatic Air Cleaners are Tricky
They cause floating air particles to be sticky. Now if they can be removed inside the air cleaner and stick to parts of the filter that might be useful. However, in some machines the sticky particles are not trapped entirely and fall on you, the dog, the floor and your furniture. If mold spores or mold biotoxins are made sticky, they merely remain in the room or stick to your body, perhaps even enter your lungs.
What is a Seal of Approval?
You have to ask yourself if you feel the government is good at evaluating filter machines. Since the EPA put toxic carpet down in its own building, I found since then I am not too trusting of government environmental science or medicine.
The best seal of approval I know of is the careful research done by a smart consumer looking at all products carefully and critically. If you decide to buy a unit that has replacement filters, consider buying one set of replacements, so they are handy. It will prevent you from leaving in old junked up filters for a long period.