Biological Consulting Services of North Florida, Inc.

Transcription

1 Biological Consulting Services of North Florida, Inc. March 11, 2008 Lee Huston SANUVAIRE, LLC (formerly JKA Company) 6435 W. Quaker St. Orchard Park, NY Re: Evaluation of the Breathe-Safe UVGI Air Sanitization Systems installed on Houston Metro Commuter Buses on the Microbiological Air quality and Coil Surface Microbial Contamination; 11 pages total Dear Mr. Huston We have conducted the microbiological analysis of the air and surface samples collected from buses containing the Breathe-Safe UVGI Air sanitizer units and from those that did not have the units installed. This was done as part of your Houston Metro UV Germicidal Irradiation study. Contact and impacted air sample agar plates were delivered to our laboratory following your monthly sampling trips to Houston, TX. The plates were incubated and microbial growth was examined and analyzed at various months following installation of the systems. Additionally, plates from buses not equipped with the air sanitization units were also evaluated. In the following pages, I have summarized the results from the various analyses. From the observed results, I can conclude that the installed units were very efficient in reducing the detectable microbial contamination from air handler coils and significantly improved the microbiological air quality of the bus interior following installation and during the duration of the test period. Should you have any further concerns please do not hesitate to contact me. Best Regards, George Lukasik, Ph.D. Sr. Laboratory Director I

2 Background Indoor air pollution is a serious health hazard affecting millions of Americans. Researchers claim it contributes to more than half of all illnesses, including sinusitis, allergic rhinitis, asthma and more. A surprising number of contaminant sources thrive in the indoor environment. Common household pollutants include dust, mold, pollen, and insect remains. Air conditioning and heating systems are perfect collection points for airborne pollutants like dust and mold spores. The moist, temperate environment is an ideal habitat for fungi and bacteria to flourish. All inside air was once outside air, so all of the dust, chemicals, pollen, insects, mold spores, and bacterial species in the outside air are eventually pulled into the air system. Moreso, people shed millions of tiny dead skin cells every hour. Once inside, these pollutants are further concentrated through growth and poor ventilation. The EPA has determined that indoor air can be 70% more polluted than outdoor air. In fact, one out of six people suffering from allergies does so as a direct result of the fungi and bacteria in their air duct systems. Air handler system maintenance improves indoor air quality and reduces respiratory suffering; it also improves system efficiency and reduces energy costs. A clean HVAC system has a longer life span and works more efficiently, resulting in lower energy bills and thus considerable savings. Most air filters remove about 10% of these pollutants allowing 90% to enter the air system. These materials collect in the air conditioner and duct surfaces, just as they do on the furniture and floor surfaces. The furniture and floor might be cleaned regularly but the duct surfaces are hidden from view. Even if the whole interior area is cleaned and disinfected, these pollutants can be released in high numbers into the interior environment again once the air system is activated. Mold and bacteria can thrive in the air handler s dark, moist, comfortable environment. Some molds, both living and dead, may produce toxins that may cause short-term allergic reactions. Long-term exposures to low levels of some mold toxins can result in permanent chemical sensitivity to common compounds in the environment. In addition to the associated health risk, air handler contamination regularly results in increased energy consumption. If the fan blades, evaporator coil or other control components of the system are heavily contaminated, the system may have to run much longer to cool or heat the occupied space, wasting a lot of energy. Reducing the sources of contaminants may lower adverse health reactions and save energy costs, which are primary advantages of keeping indoor air clean. Cleaning the air conditioning and heating system will remove allergens like dust and mold from the air distribution system that serves the indoor environment. But doing the job effectively is tedious, time consuming, and costly. Additionally, it causes service interruptions and down time which adds to the costs. Also, most biological contaminants establish tightly bound films (biofilms) onto the air handler systems, thus proper cleaning and II

3 disinfection requires a combination of superior technology and workmanship - this also comes at a price. Thus the only logical solution would be the prevention of build up and infestation of air handling systems with biofilms and debris. This will require the installation of efficient biocidal systems that decontaminate the inside surfaces of air handling systems with out compromising air flow and electrical wattage. Methods Air Sampling Mr. Lee Huston, SanUVAire, LLC (formerly JKA Company) and Ben Behimehr, Houston Metro conducted all air and surface sampling as per the recommended training and protocols BCS Laboratories provided. Air samples of bus cabins were collected at the front and back of the bus cabins. Samples were collected after the air system in a bus was run for 15 min following entry and disturbance of the inside atmosphere. Samples were collected using a SAS 180 impaction air sampler (Bio-Science international, MD) set at 100 Liters. Malt Extract Agar (MEA) was used in all sampling occasions and Cornmeal Agar was used initially to detect Stachybotrys chartarum. Surface Sampling: The air conditioning coils and ducts of the tested buses were sampled by the use of Malt Dextrose Agar contact plates (Beckton Dickinson, MD) and also Difco Hycheck (Beckton Dickinson, MD) surface sanitation testing system. Hycheck agar media containing Plate count agar with TTC and rose Bengal agar were used. Dates Mr. Lee Huston visited the Houston Metro area on the following dates to conduct the above mentioned sampling: July 10, 2007 August 11, 2007 September 7, 2007 October 11, 2007 November 8, 2007 December 18, 2007 III

4 Buses The following numbering system and buses were evaluated Numbers: Identify as "3200 Series New Flyer Buses with Carrier Air Conditioning" - these are the oldest buses in the test program Numbers: Identify as "4000 Series New Flyer Buses with Thermo King Air Conditioning" - these are the midlife buses in the test program Numbers: Identify as "3500 Series New Flyer Buses with thermo King Air Conditioning - these are new buses. Both busses with UV systems and one without were sampled Handling of Collected Samples and Microorganism Enumeration Collected samples were placed at 4 C and brought to BCS Laboratories by Mr. Lee Huston during his return trip from Houston. Upon arrival plates were incubated at 25 C for 3-7 days. The plates were then visually inspected for microbial growth and level of contamination. Colonies on the respective air sampling plates were enumerated and contact plates were photographed and visually inspected for the extent of microbial contamination. Mold and fungi Identification Air and surface plates containing fungal growth were submitted to Dr. James Kimbrough at the University of Florida Plant Pathology Department for identification. Dr. James Kimbrough is considered an authority on the identification of mold and fungal species. Attached are the reports Dr. Kimbrough provided. Results and Conclusions Initial air and air handler interior surface sampling on older busses indicated a significant level of Mold and Bacterial contamination. Newer buses contained some level of contamination but not as significant as that of the older ones. Dr. James Kimbrough (University of Florida Dept of Plant Pathology) indicated that no primary human fungal pathogens were detected in any of the samples collected prior to the installation of the UV systems. However, many of the fungi that were detected can serve as chronic allergens for people with susceptibilities and/or underlying illnesses. These fungal species can also become opportunistic pathogens in people with a challenged immune system (Elderly, young, diabetics, AIDS patients, people on certain medications, etc.). The mold reduction in the Series 3200, 4000 and 3500 showed a IV

5 95% to 99% reduction after the UVGI System was installed after six months of operation. As for the bacterial species isolated by our laboratory, most resembled species of Staphylococcus, Micrococcus and Bacillus. All identification was done morphologically, although in some cases these assumptions were confirmed by microscopy. These represent common species that are typically isolated from air and environmental surfaces. While these species are typically not primary human pathogens, they may increase chances of infection and cause respiratory distress in people. The bacterial reduction for the Series 3200, 4000 and 3500 showed a 99% reduction in bacterial species was achieved after six months of exposure to the UVGI System Following the installation of the UV systems in all cars tested, in a percentage would be a 95% to 99% decrease in the microbiological load was observed in all the buses tested. This decrease was evident by the reduced number of airborne mold species and also by reduced surface contamination on the ducts and coils of buses that contained UV systems. Figure 1. Surface contact bacteria and fungal species of the condenser coils prior to installation of the UV system (July 10, 2007), following the installation (August 11, 2007) and at the end of the study (December 18, 2007) on series 3200 buses. V

6 Figure 2. Surface contact bacteria and fungal species of the condenser coils prior to installation of the UV system (July 10, 2007), following the installation (August 11, 2007) and at the end of the study (December 18, 2007) on series 3500 buses. VI

7 Figure 3. Surface contact bacteria and fungal species isolated from the condenser coils prior to installation of the UV system (July 10, 2007), following the installation (August 11, 2007) and at the end of the study (December 18, 2007) on series 4000 buses. VII

8 7/10/2007 7/24/2007 8/7/2007 8/21/2007 9/4/2007 9/18/ /2/ /16/ /30/ /13/ /27/ /11/2007 Level of Microbial Contamination Series 3200 Series 3500 Series 4000 Dates of Bus Interior Air Sample Collection Figure 4. Bus-interior bacteriological air quality at the different test dates and different series of buses tested. Each point represents the average level of contamination of at least 4 buses. The microbial contamination of the air samples collected was rated on a scale of 0-5 depending on the number of colonies and growth on the air sampling plates. Initial air sampling prior to the installation of the UV systems was conducted on 07/11/2007. VIII

9 Figure 5. Mold contact plates from Houston Metro bus s air handling system. Sample were taken on July 11, 2007 prior to the installation of the UVGI system. Above samples were from bus numbers (starting from above left to right): 3207, 3208, 3209, 3210, 3211, 3570, 3571, 3575, 3576, 3577, 4003, 4005, 4006, and IX

10 Figure 6. Mold contact plates from Houston Metro bus s air handling system. Samples were taken on December 19, 2007; six months after the installation of the UVGI system. Above samples were from bus numbers (starting above from left to right): 3211, 3577, 3210, 4008, 3576, 3209, 4006, 3575, 3208, 4005, 3571, 3207, 4003, and Executive Summary X

11 The above presented study concluded definitely that the UVGI system efficiently removed microbial contamination from surfaces in direct contact of the systems UV rays at a rate of 95% to 99% effectiveness. The data also showed major overall improvement in the microbial air quality of the bus interior. This was very evident for old bus systems that contained air handlers with extensive microbial growth. Prior work done in our laboratory demonstrated that prototypes of these systems were very efficient (>99.99%) in the inactivation of bacterial and viral human pathogens. These challenge studies were conducted to simulate use in large air handling systems. During these studies, the system was challenged with aerosols of various human pathogens. The system s influent and effluent air was assayed for the prospective pathogens during study flow conditions. The testing was conducted to simulate the introduction of biothreat agents into air systems. The UVGI system reduced the introduced pathogens to below detectable levels. Similar studies performed by the US EPA and the National Science Foundation (NSF) have also concluded that these systems when properly installed and maintained are capable of reducing air-borne pathogens by >99.99%. The value of such a system to public health is immeasurable. The high intensity UV rays are capable of inactivating the microorganisms that have been identified by the Centers for Disease Control and Prevention (CDC) as Bioterrorism agent/diseases. These agents generally: are, or can be, easily disseminated or transmitted from person to person, result in moderate or high mortality rates, have the potential for major public health impact, might cause public panic and social disruption, and require special action for public health preparedness. Typically, UV waves exert their antimicrobial effects by penetrating the microorganism s membrane or protein coat and wielding destructive effects on the microbe s DNA and/or RNA. Since all microorganisms are composed of DNA and/or RNA, the lethality of such a system is universal as long as the system is designed well and the UV intensity is adequate. In addition to the aforementioned benefits to public health, the UVGI bus system will improve productivity by overall reducing the chances of driver and servicing technician inhalation disease episodes. Many airborne microbial pollutants can cause respiratory distress and disease when inhaled in large quantities. This is especially of concern for the elderly and persons with compromised immune or respiratory systems. Additionally, even in small doses, they may cause short-term allergic reactions. Long-term exposures to low levels of some mold toxins can result in permanent chemical sensitivity to common compounds in the environment. Bus maintenance workers and drivers are especially sensitive to the above since they are routinely exposed to the airborne microorganisms. In conclusion, I believe the UVGA system will effectively address the microbial air quality concerns, protect public health, and increase productivity. XI