First, SARS-CoV-2 was widely distributed in the air and on object surfaces in both the ICU and GW, implying a potentially high infection risk for medical staff and other close contacts. Second, the environmental contamination was greater in the ICU than in the GW; thus, stricter protective measures should be taken by medical staff working in the ICU. Third, the SARS-CoV-2 aerosol distribution characteristics in the ICU indicate that the transmission distance of SARS-CoV-2 might be 4 m. 
Initiatives are in full swing from health departments and hospital safety leaders to advance sanitization measures and decontamination initiatives in hospitals. Agencies indicate that without adequate environmental controls, patients with airborne infectious disases will pose a risk to other patients and healthcare workers. Heating, Ventilation and Air Conditioning (HVAC) expertise is essential for proper environmental management when planning control of airborne infectious disease outbreaks. This may include frequent inspection and upgrades of air filtration systems- such as HEPA Filtering and proper discharging of air to the outside (by creating negative room pressure in patient rooms and airflow management). Other initiatives like stepping up hospital safety inspections and advancing disinfecting, and sanitizing measures to include more current technologies like UV-C light disinfection.
HEPA FILTERS (Source: EPA.gov)
HEPA is a type of pleated mechanical air filter. It is an acronym for "high efficiency particulate air [filter]" (as officially defined by the U.S. Dept. of Energy). This type of air filter can theoretically remove at least 99.97% of dust, pollen, mold, bacteria, and any airborne particles with a size of 0.3 microns (µm). The diameter specification of 0.3 microns responds to the worst case; the most penetrating particle size (MPPS). Particles that are larger or smaller are trapped with even higher efficiency. Using the worst case particle size results in the worst case efficiency rating (i.e. 99.97% or better for all particle sizes).
Minimum Efficiency Reporting Values, or MERVs, report a filter's ability to capture larger particles between 0.3 and 10 microns (µm).
- This value is helpful in comparing the performance of different filters
- The rating is derived from a test method developed by the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) [see www.ashrae.org].
- The higher the MERV rating the better the filter is at trapping specific types of particles.
- See complete rating chart from 1-16
FROM THE MEDICAL FIELD
I can’t recommend a specific product but want to emphasize the importance of building HVAC systems and the number of air exchanges that take place in a room. Below I’ve included a table that summarizes guidelines from the CDC for air exchanges in various healthcare settings.
When COVID-19 made it’s presence known, we worked closely with our Facility Operations department to ensure that our exam rooms and hospital rooms were meeting these requirements. In some cases, adjusts were needed and were made. We do use HEPA filters throughout our organization which is a fairly standard technology in healthcare. We do use portable filters but only in select departments (e.g. Oncology) and have not added more for COVID-19. HEPA filters in theory are able to capture coronavirus particles but we don’t know how practical this is and I would not rely solely on this to prevent infection. Afterall, COVID-19 spread appears to be primarily occurring via droplets. It is much easier to maintain centralized units than individual ones. In addition to shoring up our ventilation systems for COVID, we also implemented physical barriers to protect our patients and staff against COVID including: dedicated negative pressure hospital units, respirators, and organizational wide face masking requirements. The key that I want to stress here is the emphasis on ventilation rather than filtration as complementary to other measures such as social distancing and masking.
5) Indoor Air Quality (IAQ) -https://www.epa.gov/indoor-air-quality-iaq/what-merv-rating-1
6) Air cleaners and HVAC filters in Offices, Schools, and Commercial Buildings
UV-C AIR SANITIZING INSTALLED IN HVAC SYSTEMS
Due to the recent pandemic, companies developing this technology are (now) on the fast track to advance UVC installations for a wide range of professional and commercial environments. Specific testing is currently underway as to the efficacy against SARS-CoV-2 (the virus that causes COVID-19) but historically, systems like those developed by Fresh-Aire UV have been tested and proven effective against pathogens that require even greater UVC dosages. "Every microorganism requires a specific UVC dosage for inactivation including the novel coronavirus. UV disinfection has been employed for decades in water treatment; these microwatt values have been used for reference to gauge UVC efficiency against a large cross-section of microorganisms. UV disinfection systems for room, surface & HVAC are (also) an ideal proactive measure to complement filtration", stated Aaron Engel, VP of Business Development at Fresh-Aire UV.
Epilogue: Straight Answers from the CDC
In our commitment to publish helpful information about innovative solutions, we rely on top health authorities to provide us with unbiased clarity and technical standards. We inquired about how UV-C Disinfecting technology truly ranked as the future solution to defeating viruses and transmitted diseases. Steve Martin, PhD, an engineer in NIOSH’s Respiratory Health Division provided us with these valuable statements:
PIERRE KORY, M.D., M.P.A.
Dr. Kory is Board Certified in Internal Medicine, Critical Care, and Pulmonary Medicine. He served as the Medical Director of the Trauma and Life Support Center at the University of Wisconsin where he was an Associate Professor and the Chief of the Critical Care Service. He is considered a pioneer and national/international expert in the field of Critical Care Ultrasound and is the senior editor of the widely read textbook “Point-of-Care Ultrasound” (winner of the President’s Choice Award for Medical Textbooks from the British Medical Association in 2015). Most recently, Dr. Kory joined the emergency volunteer team during the early COVID-19 pandemic in NYC at Mount Sinai Beth Israel Medical Center. He is also a founding member of the Front Line COVID-19 Critical Working Group (flccc.net) composed of 5 critical care experts that devised the COVID-19 treatment protocol called MATH+. (www.covid19criticalcare.com/)
Mr Engel is Vice-President of Business Development for Fresh-Aire UV, a global leader in UV disinfection technologies. Aaron has 20 years experience in the design, manufacturing and marketing of UV disinfection systems for domestic and international applications including those for residential, commercial and healthcare. Aaron has worked on projects with various groups & associations including the definitive study on UV inactivation of airborne bioterrorism agents sponsored by RTI, the United States EPA & US National Homeland Security. Aaron is frequent guest speaker and lecturer and contributes to publications on IAQ technologies and UV disinfection. Aaron is a member on various ASHRAE committees including TC2.9 Ultraviolet Air and Surface Treatment and the Programs Chair for TC2.9. www.freshaireuv.com
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