What Works Better: Ionic Air Purifiers or HEPA Air Purifiers?
Ionic and HEPA air purifiers are designed to improve indoor air quality. They are different in their effectiveness. And it's not close.
Below we give some history and break down the differences between the two types of air purifiers. We explain why HEPA air purifiers are ideal for you in almost every instance. We will also share some secrets of the air purifier industry related to ionizers.
Which Air Purifier is Most Popular?
In the 1990's, ionic air purifiers were popular. In particular, the Sharper Image Ionic Breeze.
In the early 2000's this air purifier received unfavorable reviews. This was from a result of improved testing standards.
Since then, HEPA air purifiers have become much more popular. Today, HEPA is the most common type of air purifier purchased.
How Ionic Air Purifiers Work
There are actually two types of ionic air purifiers. Electrostatic precipitators and air ionizers. In both cases these are "filter-less" air cleaners.
Electrostatic precipitators have positive and negative charged plates. Particulates collect on the plates as they pass through the air purifier. Rather than having to replace the filter, you must wash or clean the plates. While it is beneficial from a cost standpoint, you give up a lot in performance compared to a HEPA filter.
The filterless air purifiers simply do not remove the particulates effectively. They do not do a good job removing the smallest, most dangerous particles. These are the particles that float in the air for hours or days and can be breathed deep into your lungs.
An electrostatic precipitators' performance is best when the plates are clean. Yet, even at that point, it performs much worse when compared to a HEPA filter. To make matters worse, when the plates become dirty, the performance degrades further.
It is common for ozone to be produced as a by-product of the charged plates. For someone with a sensitive system such as COPD, emphysema or asthma, ozone can be a huge problem. Room air purifiers are tested to meet ozone requirements. As a result there has been a large shift away from ionic air purifiers to HEPA. It's somewhat difficult to even find these now and with good reason. In our opinion, the last thing you want an air purifier to do is introduce a pollutant into your home. Your expectation is your home will be cleaner and you can end up with high levels of ozone.
The other type of ionic air cleaner is an air ionizer. These air purifiers don’t actually have a filter. In some cases not even a motor. Rather, they emit a charge that attaches to the airborne particulates. This makes the particles like dust or pollen to stick to surfaces.
A problem with this approach is it the particles don't discriminate in what they attach to. It could be the carpeting, walls, your clothes and worst case - your lungs.
Air ionizers are not recommended for relief from allergies or any other respiratory condition.
HEPA Air Purifiers
HEPA filters were developed by the US military during World War II as a way to create an effective gas mask. The technology has not changed much since then.
For air cleaning performance, HEPA air filters are the best technology. They remove the most particles as well as the most dangerous particulates. Besides, HEPA filters become more efficient over time. Meaning they remove more with use.
Airplanes use HEPA filters. That's because they are great in removing bacteria as well as other tiny particles. They get a bad rap sometimes. On a plane the issue has more to do with whether they are moving enough air. Or your neighbor who coughs on you.
Tesla is now using HEPA filters. They even have a cool name for it. The Bioweapon Defense Mode.
HEPA air filters need replacement at some point. This is for the sake of ensuring you are getting a high level of air cleaning. As the filters collect particulates, the airflow resistance will increase. This results in less airflow through the filter and lower air cleaning performance. If the filter is clogged it simply will not be able to move enough air to clean your room.
Safety is also best. HEPA filters only use mechanical filtration. They do not generate any unwanted pollutants such as ozone. If you are looking for a recommendation, consider the Oransi Max HEPA air purifier. It is ranked #1 air purifier by an independent study at Clemson University.
In most cases when you buy a HEPA air purifier it will also have a negative ionizer. This is done to give a boost to the air cleaning performance. If you do not want a negative ionizer your choices among brands are limited. The EJ and Erik air purifiers we make do not have an ionizer. And no unwanted ozone.
As mentioned earlier, the concern with an ionizer is that it will generate ozone. The state of California requires all air purifiers to be lab tested.
Negative Ionizers are small devices that create a negative charge. They allow the HEPA filter to capture more particles. They come in different shapes and are similar in size to a dental floss container.
An Inside Look into the Ozone Testing
In the spirit of full disclosure we will show you how the ozone testing is done and what the results look like. To date, we have not seen anyone else share this type of information.
The ozone testing is done at a certified test lab in the US such as Intertek. This is an extensive test with measurements taken in many places on the air purifier. As you can see in the picture below. The negative ions can travel in different directions. So, many measurements.
The testing is performed for 8 hours with many measurements taken. To pass an air purifier must be less than 0.05 ppm.
Here are the results of the ozone test for the Finn air purifier. Results far below the 0.05ppm standard (about 99% less).
Here are the Max ozone test results. Again, far below the standard for what is considered safe. Actually, this test did not show any ozone.
Secrets Air Purifiers Companies Don't Want You to Know
There is no doubt that ozone is a dangerous gas and harmful to your lungs.
The FDA has established an ozone standard of 0.05 ppm for air purifiers. This means an air purifier must produce less than 0.05 ppm.
Some companies claim zero. Or zero ozone.
The motor can produce even a small amount. So, this is not an accurate claim.
But that's not what you should be concerned about.
The testing for ozone is done in a controlled test lab. The problem is that we do not live in test labs.
We live in homes. Homes that have other things in them like cleaning supplies and nail polish that give off fumes. These fumes when in contact with technologies like PCO or ionizers can produce ozone.
These situations are not replicated in the ozone test lab.
You can see why claiming zero ozone is a lie or at least misleading.
Check out the California Air Resources Board's research "some devices could produce unhealthful levels of ozone in more realistic conditions ... secondary reaction products such as formaldehyde may contribute to the health burden as well."
What to Look for in an Air Purifier
The air purifier must have an option to turn off the ionizer or any other technology
Our air purifiers were designed for people with sensitive systems like COPD or asthma. If they are effective and safe for this group they will work great for everyone. We make them to be safe from the ground up.
The EJ and Erik air purifiers only use mechanical filtration.
The primary filtration for the Finn and Max air purifiers is HEPA. They have a low level (1 watt or less) negative ionizer. Yet with the press of a button you can turn this off.