bipolar ionization air filtration

Simona, See below for a position statement of ASHRAE on electronic air cleaning.  Ions generating devices and ozone generating devices are mentioned.  Some questions you may want the manufacturer to answer: Whether CDC and EPA approve those devices? Do they have 3rd independent evaluation?  Not just a paid professional says it works. Are those devices studied by double blinded research papers? Are they proven to be not harmful for humans? Are they proven to work in the field, not just at the lab? Do they work specficially on SARS-coV2 the virus? https://www.ashrae.org/file%20library/about/position%20documents/filtration-and-air-cleaning-pd.pdf

Hi Simona, Adding on Luke’s notes, we also looked at Terrapin report (https://www.terrapinbrightgreen.com/report/the-nature-of-air/). We have spoken with a company and got quite solid materials, with accurate tests and validations. I am happy to share more if you are interested. My email is bam@shoparc.com. -berardo Berardo Matalucci PhD Director, Environmental Design SHoP Architects p 212.889.9005 x422 d 917.210.6780 F

We've been trying to gather information on ionization technologies and the multitude of variations it can entail... needlepoint bipolar (NPB) ionization, dielectric barrier discharge (DBD) ionization, ionization + proprietary filtration, photocatalytic oxidation (PCO), and photohydroionization (PHI)​. As you might expect, all of the variations can supply studies showing their technology is the "best" and the marketing materials are generally contradictory as a result.  They're all generally marketed to do the same thing, use electrical charges to create ions from molecules in the airstream (see image below) and control odors, particles, pathogens, static electricity, etc.  But as you mention there are also potential negatives in terms of possible ozone or formaldehyde generation, or even stray ions. (Though this video helped clear up the ion fears). The industry has somewhat clued into the O3 issue and you'll see many manufacturers list 'ozone-free technology' or similar. Though only one - that I know of - is UL 2998 listed to not produce ozone.  One of the differences we've been able to gather between the different technologies is the half-life of the ions. Some break down more quickly and stay in the HVAC equipment, others travel out into the space to 'disinfect surfaces' and the like. We actually have some of these technologies in the office and are looking to gather more data... ion counter and all. And I know others in the SMEP group are also in the same camp of "we'll provide the information we know at this point but it's by no means an endorsement of ionization technology". This mirrors the key statement from the ASHRAE position paper which states: 

... there is only significant evidence of health benefits for porous media particle filtration systems. For a few other technologies, there is evidence to suggest health benefits, but this evidence is not sufficient to formulate firm conclusions.

So while ionization technologies may help improve indoor air quality, it's much lower down on the list of strategies, IMO. All of this gets to where the conversation should start, which is gathering data on the current performance of our indoor environment and air quality: temperature, humidity, CO2, TVOC, PM2.5 and 10. Then, if we get really interested: component VOCs, NO2, CO, formaldehyde, etc. And then targeting strategies to improve what metrics we really want to improve (after first, we make sure the building is appropriately ventilated to begin with).

Team, Wonder what is the exact makeup of ions in nature to make us "healthy"?  Some suggested near waterfalls, mountain tops, etc. have a lot more negative ions than positive ions.  Are there any independent science regarding the amount of ions and the balance between negative and positive to be "healthy"?  How do indoor ion generators able to generate the right among and proportion of ions, and identify just the "bad" elements in the air to attack and not humans? Regarding Photocatalytic Oxidation (UVPCO) for Indoor air applications, there are multiple independent research papers, examples below, one from LBNL, suggested they have unwanted byproducts: https://www.semanticscholar.org/paper/Evaluation-of-Ultra-Violet-Photocatalytic-Oxidation-Hodgson-a/aa0d7403145ca5946cb8b3da53d69c7293ebf6b4 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6272289/ Regarding ionizers, see statement from EPA, and LBNL paper indicating byproducts on one manufacturer. EPA: https://www.epa.gov/indoor-air-quality-iaq/what-are-ionizers-and-other-ozone-generating-air-cleaners https://ww2.arb.ca.gov/sites/default/files/classic//research/apr/past/10-320.pdf Did anybody see the Report of Bureau of Toxic Substance Assessment Testing the Bi-Polar Ionization Product at the Glens Falls High School, Glens Falls in NY State?  What is your opinion about that report?  Feel free to email me for further discussion. Best, Luke Leung

Agree that Photocatalytic Oxidation (PCO) certainly is a technology to be more wary of in terms of byproducts. That said, we've tested these specifically and measured zero Ozone in the space, at least... results are still pending on other component VOC's and formaldehyde. I can report back on that when I know more. This product specifically is inlcuded on this really long list of indoor air cleaning devices certified by the California Air Resources Board (CARB). CARB also states on this page: 

Air cleaners that are listed as "Electronic" may emit ozone, but they have been tested and found to produce an ozone emission concentration less than 0.050 parts per million. This category includes ionizers, electrostatic precipitators, PCOs, hydroxyl generators, UV light and other electronic air cleaning technologies. Devices that likely produce unsafe levels of ozone are found on our list of potentially hazardous ozone generators sold as air purifiers.

The second list is referenced in GPS' response to the December 2018 ASHRAE Journal article about Corona Discharge Air Cleaners where they correctly point out that it's not only about ozone generation in terms of air cleaners that we need to be considering or watching out for. The September 2019 Journal issue included another manufacturer follow-up letter from AtmosAir which points out that Corona Discharge technology is just one form of an ionization process and one type of an electronic air cleaner. In that issue the original article authors state: 

The study was designed to evaluate changes in the indoor air quality of a classroom while operating a corona discharge air cleaner with a reduced fresh air flow rate provided by the ventilation system. The Department found that the concentrations of ozone, ultra-fine particles, and aldehydes increased under these conditions. The study was not designed to determine the health effects of these air pollutants, but instead was indended to test the claims that the amount of fresh air brought into a classroom can be reduced without adverse impacts on air quality. 

Maybe there are additional air pollutants we need to consider beyond particulates, O3, CO, TVOC, Formaldehyde, NO2? Are there additional component VOC's that should be included in the testing methodology beyond LEED and WELL? See image attached... My experience is only with these rating systems but I see that the AtmosAir response mentions several other component VOC's that aren't included in the established IAQ testing methodologies for these rating systems. Is the Glen Falls study the one referenced in the original December 2018 Journal article - attached? Don't want any of this to come across as me advocating for ionization, but rather sharing of information and hoping for additional dialog on the topic to learn more.  Happy to discuss via email too, but thought I'd reply here in case others are interested in this conversation. 

Love the fabulous information!  Thank you so much for sharing!  The focus of ozone on ionizers in many government institution is good.  The science of ionizers is of more interest.  Association with nature is attractive, research papers suggested the areas of interest, e.g. waterfalls, have much more negative ions than positive ions.  Does anybody know the science on what exactly is the “nature”, e.g. the number, spectral sizes, and proportion of negative and positive ions, the ionizers are modeling after? While CDC mentioned fiber filter, outside air, UVC light etc., it is silent on ionizer air cleaner for COVID-19.  Anybody aware of an independent research paper supports ionizers, which generate positive ions that some claimed to be not so positive, able to attack only the “contaminant” molecules and the specific makeup of ions are proven to have no impact, including health, on humans?