Does ozone sterilization kill the Coronavirus which causes COVID-19?

This article was originally published by Aeroqual

No medical event in recent history has made a bigger impact on global health and the economy, than Coronavirus, and the COVID-19 disease.

At the time of writing, most major economies are entering into some form of lockdown, causing significant disruption to businesses and drastically changing the way we live our lives for the next few months. 

Governments, Industry and Citizens are united in trying to slow the spread of COVID-19, to give health services time to prepare for the explosion in the demand for care. Sanitizing our homes, workplaces and public spaces is a key tactic in the fight against Coronavirus, to stop the spread of COVID-19. One method of sterilization is by using ozone. Ozone sterilization is commonly used in hospitals to sanitize equipment and significantly reduce or eliminate the spread of bacteria. Hence the question being asked is – “Can ozone sterilization kill the Coronavirus which causes the COVID-19 disease?” 

This blog post looks at the evidence and highlights the benefits of sterilizing environments with ozone, as well as it’s associated risks. 

OZONE STERILIZATION PROVEN TO KILL SARS-COV VIRUS 

There are currently no examples in the public domain, of ozone sterilization being used to kill the current strain of Coronavirus, SARS-CoV-2 (technical name of the Coronavirus which causes the COVID-19 disease). However, there are reasons to believe it would be effective: 

  • During the SARS epidemic of 2003, ozone sterilization was successfully used to purify environments infected with the deadly Coronavirus, SARS-CoV-1, the virus which causes the SARS disease. 
  •  As SARS-Cov-1 is also a member of the Coronavirus family, it is highly likely that ozone sterilization would be effective at killing SARS-CoV-2, the Coronavirus which causes the COVID-19 disease. 

HOW DOES OZONE STERILIZATION KILL CORONAVIRUSES? 

Coronaviruses are classified as “enveloped viruses”, which are typically more susceptible to “Physico-chemical challenges”. In other words, they don’t like being exposed to ozone.   

Ozone destroys this type of virus by breaking through the outer shell into the core, resulting in damage to the viral RNA. Ozone can also damage the outer shell of the virus in a process called oxidation. Put simply, exposing Coronaviruses to sufficient ozone dose (ppm x time) can result in them being 99% damaged or destroyed.

WHAT ARE THE RISKS OF OZONE STERILIZATION? 

Breathing even small amounts of ozone can be harmful. Symptoms include coughing, shortness of breath, and aggravation of lung diseases like asthma. At higher concentrations you can smell ozone, but it becomes harmful even at lower doses. For that reason, many countries have set an 8-hour exposure limit of 70 ppb (parts per billion) ozone. In the EU the limit is set even lower. Ozone is one of six common pollutants limited by the United States Environmental Protection Agency and other country’s Environmental regulators. Exposure to ozone in the workplace is controlled by the Occupational Safety and Health Administration and their counterparts around the world.  

REDUCE THE RISK OF OZONE EXPOSURE BY MONITORING 

Although ozone can sterilize coronavirus infected environments, residual ozone could also cause respiratory issues for people who breathe it in. To stop this from happening it is important to measure and control indoor and outdoor levels of ozone after sterilization has taken place. 

The problem is that the equipment for measuring ozone is either a) accurate but too expensive, or b) affordable but not accurate. This is why Aeroqual came up with option c) monitors that are both accurate and affordable

Please contact us if you have any further questions on monitoring ozone.

Ozone used for medical sterilization

Students revolutionize medical sterilization

Students revolutionize medical sterilization
Credit: Jordane Vernet/Sterilux

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Between 5% and 10% of patients admitted to modern hospitals in the developed world acquire one or more infections. The risk of health care-associated infection in developing countries is 2 to 20 times higher than in developed countries. In some developing countries, the proportion of patients affected by a health care-acquired infection can exceed 25%. In addition, many hospitals in developing countries and in disaster relief environments make do with simple disinfection of medical material but the risk of nosocomial infections remain high. Now, a company founded by EPFL students has developed a portable sterilization system that costs a fraction of the conventional equipment used in hospitals.

UV-100 Ozone Analyzer
Use the UV-100 Ozone Analyzer to verify ozone levels in the gas phase

Sterilux was founded by EPFL student, Marc Spaltenstein, who has just completed his Master degree in Life Sciences and Technologies. During an internship with a medical devices company in Neuchâtel, Spaltenstein had to come up with an effective way to sterilize medical equipment on-site. The result was the Steribox system.

The SteriBox is a portable container that can both sterilize and store medical equipment long-term. It was designed by Jordane Vernet, a graduate of École cantonale d’art de Lausanne (ECAL) and member of Sterilux, and integrates the technology that Spaltenstein developed.

HTU-500 Ozone Generator
HTU-500 Ozone Generator can produce medically pure ozone for sterilization applications.

Designed as a box with a quartz glass on the top, the SteriBox is placed in a machine that generates ultraviolet (UV) light. Only a small amount of water – less than a milliliter – is needed per sterilization cycle. Essentially, the design uses UV light to turn the air’s oxygen into ozone.

The items to be sterilized do not require any kind of preparation or wrapping. They are placed inside the SteriBox, and UV light shines through the glass fitting. This generates ozone, which in turn sterilizes the . The process simulates the oxygen-ozone cycle in the earth’s stratosphere, where ozone is used as means of converting UV radiation into heat. The sterilization is further amplified by the generation of hydroxyl radicals from water, which are powerful oxidants and can destroy even the most resistant microorganisms.

Students revolutionize medical sterilization
Credit: Jordane Vernet/Sterilux

“Of course, the SteriBox is only one part of our system,” clarifies Marc Spaltenstein. It is inserted inside the Control Station that contains the UV lamps, a system that allows ozone concentration measurement, a printer for reports on each sterilization cycle, a mini-computer, a battery that provides three days of electrical autonomy, and a computer tablet that runs the software.”

The entire procedure takes a couple of hours but the machine is turned on for five minutes only. The system uses 1,000 times less water and 100 times less electricity than conventional autoclaves; it costs up to 100 times less (compared to developed countries), and is portable, environmentally friendly and safe. The system is controlled by software developed by Gabriel De Tiberge, another EPFL student as part of his master’s thesis. The intelligent and very efficient design earned Sterilux the James Dyson Award in 2015.

Sterilizing surgical tools in hospitals is a routine procedure in private healthcare, but it is difficult to do in public hospitals and emergency and disaster health care units in . Sterilux’s system is primarily targeted to countries that do not have access to conventional sterilization equipment. However, it will also prove essential to sites where mobile sterilization is required, e.g. temporary emergency centers and clinics.