Can UV Light Kill the Novel Coronavirus?

Apr 20, 2020

As many of us feel overwhelmed while we are holed up in our homes trying to protect ourselves from the Novel Coronavirus (COVID-19), we might wonder if there is a product available to keep us safe from this deadly virus. 

This is where UV-C comes in.  UV-C irradiation is able to kill any kind of bacteria or virus. As it stands now, we do not know the UV dose necessary to kill the COVID-19 virus. Testing will need to be done to determine this. 

The amount of UV-C required to kill viruses varies from virus to virus. Here are a few examples measured in Microwatt Seconds per Square Centimeter: 

  • Adeno Virus Type III 3  🡪 4,500
  • Bacteriophage 1,3,4,5,6,9 🡪 6,600
  • Coxsakie  🡪 6,300 
  • Influenza 1,2,3,4,57,9 🡪 6,600
  • Infectious Hepatitis 1,5,7,9 🡪 8,000

As shown above, some viruses are easier to destroy than others, but all are killed by UV-C. 

Ultra-violet light (UV) is part of the electromagnetic spectrum that includes sunlight. UV light is in the high-frequency light spectrum just outside that of visible light versus infra-red that is a lower frequency of light and just below that of visible light. 

The electromagnetic spectrum is divided and measured by frequency or wavelength. 

As seen above, UV light is measured from 10 to 400 nanometers. UV light includes
UV-A, UV-B, UV-C, and Vacuum UV (UV-V).  Although all UV light will kill bacteria and viruses, UV-C light in the 254 to 260 nm range is powerfully germicidal, and, as a result, is much more effective at germ killing. 

UV-C light is germicidal. It deactivates the DNA of bacteria, viruses, and other pathogens and, as a result, destroys their ability to multiply and cause diseases. 

Specifically, UV-C light causes damage to the nucleic acid of microorganisms by forming covalent bonds between certain adjacent bases in the DNA. The formation of these bonds prevents the DNA from being unzipped for replication, and the organism is not able to reproduce. When the organism attempts to replicate, it dies. 

Products by PremierOne are designed to meet or exceed the design parameters established by Westinghouse. You need a 110 Microwatt lamp in an airflow up to 2400 CFM to get a 70 to 85 percent kill in a duct system. The lamp intensity is measured at approximately 3 feet from the lamp. As germs approach the lamp the intensity increases.  Two inches from the lamp we have 5,814 microwatts. 

We can’t block the UV-C with any type of cell or screen causing a shadowing effect.  The light must irradiate up and down the duct to give us time and distance to allow the germs to absorb the UV-C light as they flow through the duct. 

If you are trying to protect your family from spreading germs around your home through your HVAC system, you should consider installing a dual-lamp unit by PremierOne. 

Read our Article on Air Purifiers

Placing two high microwatt lamps in the duct will produce 360 microwatts of UV-C.  That will be more than three times the Westinghouse recommended intensity necessary to get an 80 percent single pass kill. It is not important to kill viruses but simply to deactivate or sterilize them so they cannot reproduce. 

The chart below is a guide to achieving an 80-percent kill rate using a 110 microwatt lamp. 

ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers), in a January 2015 position document on filtration and air cleaning states, “The effectiveness of a UV-C system to inactivate microorganisms in the air and/or on surfaces has been amply demonstrated.” 

Under ideal conditions, inactivation and/or killing rates of 90 percent or higher can be achieved. However, this will depend on several things including physical or mechanical factors.  These factors include UV-C intensity, exposure/dwell time, lamp distance and placement, as well as lamp life cycle and cleanliness. Other relevant factors include air movement and patterns, temperature, relative humidity, and air mixing. 

Airborne removal is best applied in combination with the filtration of particles with prefiltration in order to protect lamps and mechanical filtration downstream for microbial particles. 

Make your home healthier. Protect the entire home from germs, viruses, bacteria, allergens and odors by giving us a call at (509) 396-COLD (2653) and talking to us about UV-C options.

Contact your premier source for heating and air conditioning in Washington, Oregon and Idaho, Apollo Heating and Air Conditioning, at (509) 396-COLD (2653)!