There are many different kinds of air purifiers available on the market today. They achieve the goal of air purification in a broad range of ways. From traditional filters to light and invisible Ozone particles.
Review of Air Purification Technologies
There are a lot of different air purification technologies being touted on the market today, and many new ones are added every year. Most of these technologies are more magic than science. Here I’ll go over the main technologies that are available on the market today:
- HEPA Filtration
- Activated Charcoal or Carbon
- Ultraviolet Light
As you can see, there are many choices available to consumers. If you have questions about a technology not listed here, be sure to post bellow in the comments and we will do our best to answer!
Filtration is the most basic and effective form for removing contaminating particles from the air. It employs a physical media that captures and immobilizes, or traps, particles as they pass through the filtration media. You will find that there are many different types of filters available designed to capture different sized particles. The golden standard is HEPA filtration.
Out of all the air purifier technologies available, filtration is the only one that will actually remove particulates from the air! Before you run out and buy just any unit that uses a filter, check out the next section on HEPA filtration.
Mentioned above, HEPA filters are a sub-type of filter, but really deserve their own category. A fishing net is a filter as it traps things (fish) larger than the gaps in the filtration media (the holes in the net). With such a broad spectrum it’s hard to tell how well a filter will work without doing a lot of research and having specialized knowledge about the specific filtration media being used. HEPA filters on the other hand have a very specific meaning and stringent requirements that must be met before being labeled as HEPA.
HEPA filters are able to trap up to 99.9995% of particles 0.3 microns or larger in diameter. For reference, that is 100 times smaller than a single e coli cell (3 microns) and over 3000 times smaller than a human hair (100 microns)! This makes HEPA filters one of the best ways to actually remove particulate contamination from the air, and it’s used everywhere from hospitals to airplanes. HEPA filters are so effective because they physically trap contaminants the contaminants, permanently removing them from the air. As more stuff is trapped, the filter will slowly loose effectiveness as less and less air is able to be pushed through it. This means you must periodically replace the filter to be effective. The cleaner the air is that the filter is processing, the longer it will remain good for.
We strongly recommend air purifiers that use a HEPA filter as this is truly the best way to remove contaminants from the air!
Activated Charcoal or Carbon
Have you ever smelled paint? That smell is not from particles in the air, but something called Volatile Organic Compounds, or VOC’s. These are chemical gases in the air that can be very difficult to remove. Activated charcoal or carbon filters (charcoal and carbon are synonymous) will absorb these VOC’s removing them from the air. They do not remove any particulate, just the chemical vapors.
A lot of people rely on 3M’s respirator with an “organics” filter which is an activated carbon filter. We can personally attest to how well activated carbon works.
If you’re fighting odor, you want to have an air purifier with activated charcoal or carbon filter. You’ll also want to make sure that you change the filters as needed to ensure everything is working optimally.
Ultraviolet (UV) Light
If you have ever been in a lab, hospital, or even camping you might be familiar with UV light sterilization. The high-energy UV rays are able to kill just about any microorganism with a sufficient dose. Notice what we said there, a sufficient dose. For UV sterilization to work well you need powerful UV lights and extended exposure, neither of which any air purifier on the market does. First, just as UV light can kill microorganisms, it’s also dangerous for our skin and absolutely brutal on just about any material it strikes. You know how colors fade and plastic cracks when exposed to the sun? That’s because the UV rays are damaging the materials!
Just about the only material that can hold up to extended exposure to UV light is stainless steel. The image to the right shows a commercial UV purification system that has UV sources powerful enough to kill the microorganisms as they pass through.
UV light works very well in a carefully controlled industrial/commercial setting. But save your money when buying an air purifier for your home. We do not recommend UV purifiers.
Ozone is an incredibly dangerous gas. It’s colorless, but has a sharp odor similar to that of chlorine. Studies have shown that people can detect the odor at concentrations as low as 10 parts per billion (ppb). If you remember high school chemistry you know that oxygen in the air usually forms molecules with only two oxygen atoms, but ozone has a third stuck on making it incredibly unstable, reactive, and dangerous! If you want to know more about ozone, check out the wiki page here. There’s also so much dangerous misinformation out there, the EPA even has a special page to inform the public about the hazards associated with ozone air purifiers.
Here’s a quote about ozone from the EPA:
When inhaled, ozone can damage the lungs. Relatively low amounts of ozone can cause chest pain, coughing, shortness of breath and, throat irritation. It may also worsen chronic respiratory diseases such as asthma as well as compromise the ability of the body to fight respiratory infections… The concentration of ozone would have to greatly exceed health standards to be effective in removing most indoor air contaminants. In the process of reacting with chemicals indoors, ozone can produce other chemicals that themselves can be irritating and corrosive.
Seriously, ozone is bad stuff and you don’t want it in your house! To be effective it has to have a minimum concentration 10 times higher than when people can start to detect a chlorine smell. It’s also incredibly harmful to your body and anything living in your house!
In short, ozone air purifiers are at best minimally harmful to humans. They are fairly useless for everyday cleaning. And, worst of all they are extremely dangerous to your health!
We think it’s important to purchase what you need, and nothing more. However, to remove dust, allergens, hair, purchase a HEPA purifier that’s rated slightly larger than you think you need. If you’re trying to remove odor buy an activated carbon or charcoal air purifier.
Check out the following guides for more info:
Or, if you would like to learn more, check out these informational articles:
Hope you liked the article. Good luck in your search!