I have seen the question air purifier vs air ionizer asked in some social media, so if you want to find out more about this issue, keep reading.
I guess it is best to start by saying that this is not the right question because it cannot be one versus another, i.e., an air ionizer vs an air purifier. This is simply because these things belong to the same category. This is about cleaning the home air, so an ionizer is a device that contributes to the cleaning and purifying of the air.
There are devices designed to work only as ionizers, but you will frequently see an air purifier that has ionization as one stage in the process of air filtration. You have such devices in this list of air purifiers with ionizers.
A typical HEPA air purifier works by sucking the room air into the device with the help of a fan, this traps airborne contaminants and let the clean air goes out. This is repeated a few times per hour, with the whole room air passing through the filter. So this is a mechanical process of removing particles from the air.
But such cleaning can be even more effective by releasing ions in the air, these are usually negative ions and those tend to bond with pollutants and impurities in the air passing through the ionizer chamber. According to the manufacturers, there are at least two effects of this.
First, pollutants may bond creating heavier particles so the air cannot spread them around and they start falling onto the floor. You have such examples in purifiers that use the Sharp Plasmacluster technology developed by Sharp. They emit both positive and negative ions into a room. Similar to this is what is known as the Plasmawave technology by Winix.
Second, they may be attracted to and collected by a plate inside of the purifier and in such a way they are removed from the air, see the picture from Wikimedia. This type is usually described as an electrostatic precipitator or ESP. More about this you can read on Wikipedia.
I have seen some statements that having such an electrostatic charge improves cleaning efficiency for 20-60% in the sub-micron size range. Here is a graph form one scientific study under the title “Effectiveness of Home Air Cleaners in Reducing Indoor Levels of Particles” that shows that an electrostatic filter outperforms a mechanical filter in the range of particles sizes 0.1-1 micron.
Note that some ionizers generate ozone as well, but this gas should be avoided in larger quantities. This is why you can have the warning to use it in unoccupied rooms only as in the case of this Airthereal MA5000 device shown in the picture:
In some of these devices you have ozone generators as an option, and it can be switched off, as in this Ivation 5-in-1 HEPA Air Purifier & Ozone Generator, Ionizer & Deodorizer.
Here is a nice video showing some details about the mentioned Winix Plasmawave Technology, please have a look:
So the bottom line is, having an ionizer included in your air purifier is normally a bonus. From what I have seen in the reports, there are no negative effects or health hazards from having such an ionizer. But this may not be so if ozone is generated in larger quantities.
Thank you for reading. Please use the comment box below in the case of questions or comments. Have a nice day.