FAQ – Frequently Asked Questions about Ozone

Ozone or trioxygen (O3) is a gas that is made up of electrically charged oxygen particles. It is heavier than air making it ideal for purifying air and sanitising, disinfecting, sterilising and deodorising whatever it comes into contact with more effectively and efficiently than can be done by hand or using disinfectants.

There are a number of benefits to using ozone:-

  • Ozone is far more effective than the best liquid disinfectants available.
  • Ozone begins to work instantly and faster than liquid disinfectant.
  • Unlike liquid disinfectant, ozone does not leave any toxic residue on surfaces or food.
  • Ozone also kills airborne bacteria and viruses
  • It is environmentally friendly, unused ozone reverts to oxygen (O2).

While ozone is an extremely effective way to destroy the virus and other bacteria,  Envirusafe recommends that ozone treatment should be used as part of a full cleaning regime, and to provide an added layer of protection, NOT as a total replacement.

Ozone is an unstable gas with a half-life and will naturally breakdown and begin to decompose overtime, reverting back to its original form of oxygen.

The time it takes to completely dissipate depends on several factors including the concentration of ozone in the room, the ambient temperature, how much of the ozone is used during the sanitisation process how much work the ozone has to do and the amount of ventilation that the room has.

The Mountain Fresh range of ozone sanitisers only produce low levels of ozone.

When using high levels of ozone to shock treat a room, time needs to be given for the ozone to breakdown or be flushed  from the space. Opening the doors and windows will and using a fan, for example will speed up the removal and breakdown process.

Active carbon filters can also be used to speed up the destruction process of ozone. This is ideal for when a room needs to be sanitised using high concentration levels and it needs to be reoccupied in a short space of time.

It is advisable to use an ozone meter to check that the ozone is below the recommended safety levels.

Always follow the instructions.

Ozone is created by passing oxygen through a high electrical charge. The oxygen molecules split into charged atoms which react with other oxygen molecules and creates ozone. Ozone is unstable and reverts back to oxygen making it a very environmental way to disinfect and sanitise anything that it comes in contact with.

how do ozomne generators work ade graphic

No, once you own the ozone generation machine it costs around the same as a standard light bulb to run, making them a far cheaper option than traditional chemical based cleaning methods. Ozone is then created on demand.


An ozone generator creates ozone gas on demand in the room that is being treated. It begins work immediately as it comes into contact with any airborne pathogens, bacteria and viruses.

Ozone is heavier than air and will continue to sanitise all exposed surfaces in the room.

The time is takes depends on the size of the room and how infected the room is.

Any remaining ozone once it has done its job begins to break down, dissipating, decomposing and reverting back to oxygen leaving the room and everything in it sanitised with no toxic residue to deal with.

Coronaviruses are a family of viruses that cause colds and flu as well as SARS and MERS. Ozone destroys all of these viruses including Covid-19.

A recent scientific study in Japan showed that even low levels of 1ppm or less of ozone destroyed 90% of COVID-19.

can ozone kill covid-19

The corona virus is known as an "enveloped virus" This envelope or casing is made of a protein. Ozone kills the virus by breaking down, or oxidising the protein casing of the virus.

how does ozone kill the covid 19 virus

Yes, ozone has been known and used as an anti-pathogenic for many years. It has been proven in numerous scientific to be highly effective at killing pathogens like coronaviruses. It is highly effective for airborne pathogen as well as those on surfaces. Ozone is also widely used in waste water treatment plants across the world.

It is also shown to be very effective in destroying HIV, hepatitis A and B, the Norwalk virus, Parvoviruses and a range of other “enveloped” and “naked” viruses as well as most harmful bacterias.

Ozone attacks and penetrates the outer protein shell of the virus which begins the destruction of the virus.

can ozone kill the caronavirus

It depends on a number of factors like the size of the space being treated, temperature and the level of contaminants in the room. Once the correct level of ozone is reached it takes about 30 minutes to do its thing although ozone begins its work immediately and can begin to destroy coronaviruses in as little as 20 seconds.

There are two ways to treat a space.

Mountain Fresh Low Level Units

Trickle treatment - Low levels of ozone that can be used in communal spaces that are not permanently occupied but has a constant through-flow of traffic. These include public toilets, shower rooms, dining areas, kitchens, meeting and conference rooms, hallways and other communal areas. These units can be used on a timer or continually for high trafficked areas. The ozone produced in low level units is either used up in the sanitisation and disinfection process or breaks down due to its half life. For occupied spaces, like an office, for example, the units can be set using a timer to come on once the office is closed and left to sanitise the space overnight.

Pro and Fan Assisted Range

Shock Treatment - Higher levels of ozone are produced to treat a space. It is important that the room is closed up and that no people or animals are allowed into the room during the sanitisation process and enough time is left for the breakdown of the remaining ozone into its original form of oxygen or it flushed out through ventilation or destroyed using a carbon destructor before people or animals are allowed back into the room.



It is important that the safety instructions for these units are followed correctly.

Ozone at high levels can be dangerous to humans and animals and therefore care must be taken to flush the remaining ozone from the room once the  sanitisation process has been completed.

No, ozone is made up of electrically charged oxygen atoms which, after a short time, reverts back to oxygen and it cannot be stored. Ozone is therefore produced at the point of use, on demand using an ozone generator.


Ozone, in high concentrations, like any other cleaning material such as chlorine based disinfectants or ammonia needs to be treated with caution and should be used with a certain amount of care and can be dangerous to health.

The recommended exposure limit for ozone is 0.1 ppm (0.2 mg/m3). Ozone levels of 5 ppm or higher are considered a danger to health. When ozone is used at high levels, steps must be taken to flush the remaining ozone from the room before it is reoccupied.

When using high levels of ozone it is recommended that you use an ozone meter to test the levels are within the safe levels.

Chemicals like chlorine and bleach are highly toxic and can be very dangerous to use.

Unlike, chemical disinfectants there have been no deaths recorded that have been caused by the use of ozone in over 120 years.

Ozone is much safer and carries far less risks than any other alternative ways of cleaning. At low levels ozone is used to deodorise public toilets, reception areas and care homes for example.

For occupied spaces ozone concentration must be kept below the recommended safety levels. which is 0.1 ppm (0.2 mg/m3).

In high concentrations, long term exposure to ozone can cause respiratory and other health issues.

No, while ozone is a very effective way to sanitise and disinfect a space, there are many different factors that can affect the potency of the ozone and it should therefore be considered as an additional layer of protection, not as the sole cleaning solution.

A good cleaning regime is important and each step you take will contribute to making your business a safer place for you, your staff and customers.


Ozone should be used as an additional part of your current cleaning regime and has many benefits.

Some areas, like a public toilet or washrooms, for example, are difficult to keep sanitised. Especially, things like the door handles and taps which are being touched by everyone using the facility and it is not practical to clean after every user. Ozone being an  automated process can help keep these items sanitised.

Ozone is a gas and therefore also permeates hard to reach and inaccessible areas.

A low level ozone machine can be left to get on quietly helping to sanitise a space 24/7.

Ozone is a very powerful disinfectant and is used to sanitise and disinfect operating theatres and sterilise medical equipment. However, like any powerful cleaning agent care has to be taken when using ozone.

High level Ozone generators should not be used in occupied, enclosed spaces. This includes people and animals.

Ozone works through oxidation and, when used long term, at high levels, can have a detrimental effect on plants and some electronics for example.

Before using an ozone generator make sure you speak to one of our technical team to best understand the ideal solution for your situation.

Ozone has been used for many years for many different applications.

  • Industrial
  • Commercial
  • Medical

Ozone gas can be infused in water and used as a non-chemical disinfectant to sanitise hard surfaces as well as food items like meat, fruit and vegetables.

Ozone is used to sanitise, disinfect, sterilise and deodorise:-

  • Water treatment plants to kill bacteria
  • Food and meat processing plants
  • Breweries - ozone leaves no chemical or toxic residue so ideal to clean and sterilise brewing equipment
  • Fishing trawlers - To remove the smell and prolong the life of the fish.
  • Butchers shops
  • Care and residential homes
  • Barbers, hairdressers and beauty salons
  • Bars, Pubs and Restaurants
  • Commercial kitchens in restaurants
  • Commercial cleaning companies
  • Flood damage and restoration companies
  • Operating theatres and medical centres
  • Buses, coaches, trains & taxis
  • Hotels and holiday rental accommodation
  • Caravan parks, boats and motorhome rentals.
  • Schools, nurseries and universities

Ozone has many uses and not only is it a powerful disinfectant, it has also been used for years as a deodoriser.

Unlike, air fresheners that just mask the smells, ozone destroys the bacteria that causes them, so is a good way to permanently remove offensive smells.

Difficult to reach spaces, like under the seats of a car, where maybe, milk has been spilt and turned sour or vomit, for example. Ozone will kill the bacteria that causes the smell and is therefore a permanent  solution. The smell of cigarette smoke can also be very difficult to get rid of and ozone does a great job of removing the smell from cars, furniture, hotel rooms and other spaces.

Ozone can be used to deodorise and remove the smell of:

  • Fire smoke
  • Cigarette smoke
  • Urine/Faeces
  • vomit
  • Animals
  • Mould & Damp smells
  • Strong food smells (like curry and fish)

An ozone meter can be used to detect the level of ozone in a room.

When setting up a trickle charge unit it should be checked every few hours to be able to set the machine to dispense the correct amount of ozone to do its work and keep within the recommended safety levels. This can be either reducing the production level or setting it on a timer.

For high level ozone treatment then once the unit has completed the sanitisation process, and time has been given for any remaining ozone to dissipate or revert to oxygen, an ozone meter should be used to test the levels to ensure that they are below the recommended safe levels.


Please contact us if you have any questions that are not answered above.