Posted 2/11/2019 9:43 PM (GMT -7)
Not that it matters much to many, but we use ionizers both in some of our our air purifiers and in the industry in general as they serve a variety of purposes. They are also common for control of static charges and materials handling. Every time you brush your hair with a plastic comb you experience their effects. Heck, they are all around us, all the time.
A negative ion is nothing more than a charged molecule or atom, otherwise known as an anion (negative) or ion (positive). You can use the effects of them to attract or repel other ions/anions etc hence the usefulness in certain industrial/commercial applications where you might want to attract, repel or neutralize something else with a charge i.e. Styrofoam or while working with electronics, or static charge control etc.
The issue with gadget'y (cheap) home air purifiers normally referred to as ionizers aside from the fact there is usually no actual filter which renders it basically useless - anyway the issue is primarily ozone production due to the high voltage required to impart the charge on the molecules within the air. Some of them pump out a lot of ozone. It is the excessive ozone that is doing the aggravating in those with lung issues. You can however avoid the production of ozone, but these are more expensive/commercial systems in the $1,000+ range. You can also avoid the majority of ozone production by keeping the voltage used to below 4,000 volts in some mechanical equipment like electrostatic filters.
Using an ionizer or negative ion generator around your bed - well if you ensure that it is non-ozone generating then about the worst that can happen is you wake up covered in dust cause well - a lot of negative ions will simply attract a lot of positive ions... ie. dust.