In this ASHRAE Journal article, research scientists from the New York State Department of Health determined that operating a corona discharge (sometimes labeled: ionizing, negative ion, bipolar ionizing, activated oxygen, mountain fresh air, etc.) causes an increase in indoor ozone concentration, ultrafine particulates, aldehydes and acetone.  Consequently, they have decided these types of products cannot be used in schools in New York State. 

Fortunately, there are other air cleaning solutions, like enVerid's HLR technology, that do not degrade air quality and use the well-understood and safe process of adsorption.  

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