Dr. Harriet Burge
Thanks for taking the time to
comment on the Environmental Reporter article. I agree that there are many different modalities for air
cleaning. My focus is generally to make indoor environments sufficiently clean and well ventilated, either
naturally or using central systems, that separate air cleaning is not necessary. Where this cannot be
accomplished or where specific problems exist that mandate their use, room air cleaners can be very
Can air cleaners be used
in place of fixing the water problem, normal forms of remediation, or removing the sources of fungal
No. In my opinion, it is clear
that water problems must be fixed and any mold growth must be physically removed from the building. Air
cleaners serve other purposes and are not a surrogate for fixing the root cause and physically removing
areas of mold growth.
Were you aware of the
poor performance results for the Ionic Breeze as reported by Consumer Reports?
Yes. Consumer Reports did a Clean Air Delivery Rate Test (CADR). This test measures how fast
particles are removed from the air. The Ionic Breeze is not as fast as fan-driven HEPA units and,
therefore, will not keep particle levels really low if there is a continuously emitting source. If
continuous sources are present, operating the Ionic Breeze will decrease bacterial and fungal particles by
about 40%. The units do efficiently remove bacteria (and kill them if you use the UV feature) and fungal
spores from the air that passes through them. The air emitted from the units is clean, and they cut the
time at least in half for concentrations to reach the 1% level. If somebody needs, or would like 'really
clean' air throughout a room, they should use a device with a fan that moves a large volue of air and a
filter that is at least equivalent to ASHRAE dust spot 85%. It should be noted that these units must remain
on all the time, and they do make noise. I feel it is worth reiterating that there are good data available
documenting that people turn off air cleaners because of the noise, even in occupational spaces where the
airborne particles are clearly hazardous (e.g., radioactive). One client noted that there are also very
quiet HEPA (and near HEPA) filters. They cited Austin Air, and Aerox as good quality HEPA filtration
devices that remove VOCs with activated carbon beds from which they have heard good feedback.
Where did the data come
from for the efficiency of air cleaners that use electrostatic precipitation?
The data referred to in the article was gathered from research personally performed by me. This
research was paid for by Sharper Image (SI) and, no, I do not own any SI stock, nor do I benefit from
increased sales of the Ionic Breeze. SI had no input in the protocol, data analysis, or interpretation of
the data, which is now being prepared for publication. It is likely that there are many other electrostatic
precipitators on the market that function equally well, or even better. The Ionic Breeze was mentioned by
name simply because I had first hand knowledge of its efficiency. I am not implying that it is the only
device that will work. It is also important to note that the reduction in bioaerosol concentration also
depends upon factors such as the size of the room, air currents, activity levels, and whether there are
continuing sources of spores. Also note that gravity alone causes a reduction in airborne spore
concentrations, subject to constraints such as no continuing sources.
What about ozone?
There were actually several comments related to ozone. The comments ranged from people who had
clients who believed that their electrostatic precipitator was creating ozone, to discussions and a few
articles assessing its use in cleaning air. For instance the ozone output of the Ionic Breeze has been
intensively studied, and should not be high enough to produce odors. If you do use an Ionic Breeze (we can
only speak about the device from which we have first hand knowledge), you shouldn't be able to smell the
ozone. If you can, something is wrong. If the blades get really dirty, ozone emissions might go up.
Otherwise, take the unit back and get a new one or, if you've decided you don't like it, just return it. To
the larger question of the general use of ozone in fungal investigations, this is a broad topic and we will
address this in a future issue of the Environmental Reporter.
On a personal note, I really
appreciate all the comments we have received from this short article. It is this kind of discussion that
stimulates all of us to keep on the cutting edge. Please continue to respond to the information we
generate. I personally guarantee that we take all comments seriously, and we as a company, have learned a
great deal from my contacts with you.
Clearly, we all realize that
this is a complex topic with a wide variety of opinions. The data continues to be difficult to summarize or
to accurately account for the multitude of possible applications. Our hope is that this has at least
catalyzed some thought and perhaps even provided some new data for consideration. As always, we welcome
your comments and recognize the many thousands of years experience represented by our clients. It is truly
the case that we often learn from you.
With best wishes,
The data and other information contained in
this newsletter are provided for informational purposes only and should not be relied upon for any other
purpose. Environmental Microbiology Laboratory, Inc. hereby disclaims any liability for any and all direct,
indirect, punitive, incidental, special or consequential damages arising out of the use or interpretation
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