Dr. Gabor Lantos MD.P.ENG.MBA Head of Occupational Health Management Services Inc. Toronto, Barries, London, Vancouver
Dear Mr. Weinberg:
You have asked me for my professional opinion regarding the potential use of the Wein Air Supply Ionic Air Purifiers as adjunctive self-protection for healthcare workers and for other individuals who might be contacts of the SARS virus or other infectious agents.
As an Occupational Health consultant to many of Toronto’s teaching hospitals I have been much involved with containing the recent SARS outbreaks and have made both private and public submissions to the Ontario Commission to Investigate the Introduction and Spread of SARS in Ontario (www.sarscommission.ca My own submission of November 17th begins on page 165 of the transcript).
For the reasons that follow, it is my professional opinion, both as a professional engineer and as an occupational physician, that both the room-size and the neck-worn air purifier can be of significant benefit in mitigating the risks from SARS, as well as from other common airborne pathogens such as the “common cold” coronaviruses, tuberculosis, and Influenza A & B.
Current medical knowledge about SARS is not adequate for prevention and is not reliable for treatment. Immunoprophylactic means do not yet exist and early therapeutic trials for the afflicted have been ineffective and even harmful. Until such time as effective immunizations and/or therapies are developed and readily available, the emphasis must be on preventative measures.
The successful containment of the SARS outbreaks was predicated on Public Heath interventions, Environmental Controls, and Personal Protection Equipment. Traditional Infection Control policies and procedures were insufficient. As per a recent CDC publication (Emerging Infectious Diseases Vol. 9, No. 10, October 2003): “To prevent the spread of SARS we implemented strict respiratory and contact precautions”.
The World Health Organization's investigation of Hong Kong's Amoy Garden Apartments revealed how the infection was spread via interconnected airstreams throughout the building.
The rationale for the use of Ionic Air Purifiers is that ion emission reduces the concentration of airborne particles. Aerosolized pathogens and contaminated airborne droplets become charged and precipitate on nearby surfaces: no longer to be inhaled. Early studies conducted by the UCLA Department of Microbiology simulated the airstream characteristics of human breathing, “mimicking real-life usage” of the neck-worn instrument. They showed a “consistently reproducible”, 90% reduction of airborne bacteria. Dr. Spira, the medical director, by virtue of the experiments we have conducted, the results suggest that we could significantly reduce the risk of pneumonia especially those contracted in hospitals.
This last statement is particularly noteworthy given the fact that at least half of the SARS cases in Toronto were acquired in hospitals (nosocomially).
Later research conducted at the University of Cincinnati Medical Center's Division of Environmental and Industrial Hygiene/Health Related Aerosol Studies were published in the peer-reviewed Journal of Aerosol Science Vo.32, SI, September 2001, and subsequently presented at the European Aerosol Conference in Germany. It was found that depending on particle size, operational time, and other variables, anywhere from 79-97% of particles were removed from room air. This size range includes particles of bacteria, molds, and viruses. The most recent Summer 2003 studies by the lead authors Drs. Grinshpun and MacKay showed that whereas a surgical mask alone reduces by 75% the total number of inhaled organisms, the combination of a surgical mask and the VI3500 Vortex* room air purifier resulted in a 99.5% reduction of inhaled infectious particles.
Respirators(masks) and ionic air purifiers used together created a synergistic system. Not only does the air purifier reduce the upstream concentration of particles, but it also enhances the filtering performance of the respirator because charged particles are more effectively filtered than are electrically neutral ones. There are well known difficulties with the sourcing, securing, fitting, and wearing of N95's. The effectiveness of a standard surgical mask together with an ionic air purifier is equal to or greater than that of an N95 alone.
Reducing the concentration of airborne particulates reduces the risk of infection. As per Nardel E.A., and Macher J.M., (Respiratory Infection Transmission and Infection Control Chapter 9, Bioaerosols: Assessment and Control ACGIH 1999) “the expected number of cases among a given number of susceptible persons is proportional to the average concentration of infection droplet nuclei in a room, and the probability that the particles will be inhaled”.
In summary, it is my professional opinion that the use of the air purifier alone, or in high risk settings as adjuncts to masks, respirators, and other PPE, will significantly reduce the risk of contracting airborne infections.
— Dr. Gabor Lantos P.Eng MBA MD
Occupational Physcian & Professional Engineer
*This document orginally pertained to the VI2500 Vortex, Wein Products, Inc.