IQAir Filters and Airborne Biological Warfare. Do they Help? Air filtration for indoor air quality control of biological contaminants - creating safe rooms by Frank Hammes, President IQAir North America

Editor's note: I asked Frank to put together some information for us due to the number of questions we are being asked about Bioterrorism and whether air purifiers would help.

IQAir advanced air cleaning systems have not been designed for, nor are there any claims made as to their effectiveness as a civilian bio-defense measure. IQAir believes that based upon IQAir total system efficiency for airborne particles and the option to create positive pressure areas, IQAir systems are capable in certain circumstances to reduce indoor exposure to airborne weaponized biological contaminants (AWBCs). The actual effectiveness in protecting individuals will depend on many factors outside the control of IQAir and its users. For this reason, IQAir does not make any promises or guarantees regarding the actual protection afforded by IQAir systems against AWBC exposure.
IQAir agrees with most experts that the statistical risk of exposure to AWBCs is very small. IQAir nevertheless feels responsible to comment on the possible contribution air cleaning, if properly implemented, could make in reducing exposure to AWBCs.
This article only considers air filtration in relation to indoor inhalation exposure to AWBCs. It does not address the exposure to AWBCs outside buildings, nor does it address the exposure to bio-contaminants arising out of surface contact or ingestion.
In the event, that bio-terrorists target specific buildings, these specific indoor environments pose an isolated exposure risk to occupants of that building. IQAir feels that the potential benefit of its systems will be very limited, since terrorists may be able to intentionally circumvent such a filtration measure.
If AWBCs are aerosolized outdoors (e.g. through airplanes, missiles, bombs) the greatest threat of exposure is outside buildings. In this instance, buildings may offer shelter from AWBC exposure and air filtration may add some degree of protection.
IQAir offers stand-alone, room-based filtration systems, which may reduce the potential risk of indoor exposure to AWBCs by:
* filtration of contaminated outdoor air before it enters buildings
* filtration of indoor air (recirculation)
In the case of outdoor aerosolization of AWBCs, the filtration of outdoor air before it enters the indoor environment is a priority.
In buildings with centralized forced ventilation, the filtration of the forced air stream would help to reduce the infiltration of AWBCs. IQAir does not currently offer filtration products for forced ventilation systems. HVAC contractors and HVAC filter suppliers are best positioned to give information about the filtration that these system offers and any filter upgrade possibility.
In buildings that do not have forced air ventilation, such as many residential buildings, AWBCs could enter indoors through "natural ventilation" such as open windows, ventilation openings, cracks around windows and doors, etc.. The most effective way, to reduce the infiltration of AWBCs in such naturally ventilated buildings is to create a positive air pressure area by pumping filtered outside air into the building and using ventilation openings and cracks to leak indoor air outdoors and not vice versa.
IQAir offers positive pressure air cleaning systems that consist of positive pressure accessories (IQAir Inflow W125 or IQAir Outflow W125) that if used in conjunction with an IQAir particulate air cleaning system can reduce the amount of unfiltered air leaking into a room through gaps and cracks. For more information, please refer to our "InFlow Wall Ducting Kit: InFlow W125".
Whether IQAir systems are used to reduce leakage of contaminants into buildings or to clean indoor air through recirculation, IQAir advanced air cleaning devices are capable and suitable in retaining airborne biological particles, of which AWBCs are a part. The following IQAir systems are certified by IQAir to filter airborne contamination particles which are 0.3 microns in size or larger with a total system efficiency of 99.97% or greater: IQAir HealthPro, IQAir HealthPro Plus, and IQAir Cleanroom H13.
Since most AWBCs, such as anthrax spores, are approximately 1 (one) micron in size, these IQAir devices can be expected to filter AWBCs in this size range with an efficiency of greater than 99.97%. This however, does not mean that the air in a room with an IQAir device will be 99.97% AWBC-free, as the reduction of AWBCs depends not only on the system efficiency, but also on factors which are specific to the indoor environment, such as room size, source, type and concentration of AWBCs, airflow patterns and ventilation rate.
IQAir offers for consideration that while the health risks posed by bio-terrorism are remote, the exposure to air pollution, through tobacco smoke, traffic and chemicals to millions of individuals is very real.
If anything positive comes out of the potential threat of AWBCs, it is a heightened public awareness that good air quality should not be taken for granted. And while man can go without food or water for days, he can only hold his breath for seconds.