Why ambulance disinfection is more than just hygiene
An ambulance is the only medical space that can serve over a dozen patients with completely different health conditions during a single shift, often without time for a full cleaning procedure between dispatches. The disinfection of the ambulance interior directly affects whether the next patient enters an environment free from pathogens left by the previously transported one.
For fleet managers, it is a practical question: how to reconcile biocidal efficacy with vehicle downtime, personnel safety, and operating costs. Since 2020, several technologies have appeared on the market that promise an answer – from UV lamps to ozone and plasma generators. However, none works equally well in the conditions of an ambulance, where space is tight and the interior is full of sensitive medical electronics.
How the approach to ambulance disinfection has changed since 2020
The approach has shifted from the rule of “disinfect after every patient without exception” towards risk assessment – although the path to this was not linear.
At the beginning of the pandemic, a maximalist approach dominated: intensive disinfection after every transport, often without distinguishing whether the patient had a confirmed infection or only a suspected one. In March 2021, the Security and Crisis Management Department of the Mazovian Voivodeship Office sent guidelines to the Voivodeship Emergency Medical Service Station, according to which an ambulance did not require full decontamination after a patient with confirmed SARS-CoV-2 infection if the next transport also involved an infected person – airing for 15–20 minutes and spraying the stretcher with a disinfectant was supposed to be sufficient.
This official position of a crisis institution well illustrates the direction of the change. The emergency medical system, facing an increasing number of dispatches with a limited number of teams, began to differentiate the procedure depending on the real epidemiological risk, instead of applying a single maximum procedure to every case. However, this does not mean that the shortened procedure replaced full disinfection as a general rule. The applicable standard remains full disinfection of surfaces in contact with the patient after every transport, according to the instructions of the reusable equipment manufacturer. The new physical technologies described below are intended to speed up this procedure. Shortened airing in itself is not one of them.
Ozonation – how it works and where it makes sense in an ambulance
Operating principle and effectiveness
Ozone (O₃) is a strong oxidant that destroys the cell membranes of bacteria and viral envelopes, reaching places that are difficult to access by manual wiping – crevices, upholstery, inside ventilation ducts. However, effectiveness depends on three variables: gas concentration, exposure time, and space volume. The treatment time provided by manufacturers of devices tested in large hospital wards does not necessarily translate directly to the tight interior of an ambulance.
Limitations: emptying the vehicle, impact on materials, waiting time
Ozone in biocidally effective concentrations is toxic to the respiratory tract, so the vehicle must be completely emptied for the duration of the treatment and thoroughly aired out after its completion.
The impact of ozone on electronics is sometimes presented ambiguously. As indicated by industry sources dealing with this technology, e.g., wojrat.pl, the vehicle’s electronic circuits themselves do not react to ozone directly – failures after the treatment usually result from moisture or previous damage. An accelerated degradation of rubber and some plastics remains a well-documented phenomenon.
To summarize the real risks with frequent use of ozone in an ambulance:
- toxicity to the respiratory tract at biocidally effective concentrations – the vehicle must be completely empty during the treatment;
- degradation of rubber and some plastics – cracking, crumbling, discoloration;
- possible accelerated corrosion of unprotected electrical connectors with frequent, high-concentration treatments;
- extended vehicle downtime, partially negating the time benefit for which the technology is chosen.
In the densely packed interior of an ambulance, where monitors, infusion pumps, and ventilators operate, this uncertainty weighs more than in a regular passenger car. The resistance of the casings of specific medical equipment to ozone must be consulted directly with its manufacturer before regular treatments are implemented.
UV-C and UV 222 nm (Far-UVC) lamps – what is the difference
Classic UV-C lamps with a wavelength of 254 nm and newer Far-UVC lamps with a wavelength of 222 nm differ primarily in whether they can operate in the presence of humans – and this directly translates to the time it takes for the team to return to work in the disinfected ambulance.
UV-C 254 nm vs. UV 222 nm
The 254 nm radiation effectively destroys the DNA and RNA of microorganisms, but the same mechanism harms human skin and the cornea of the eye, which is why the treatment requires an empty vehicle and closed doors. The 222 nm light works on a similar biocidal principle, but is strongly absorbed already in the dead layer of the epidermis and the outer layer of the cornea, so it does not reach the living cells located deeper. In comparative studies, 222 nm radiation shows an effectiveness comparable to or higher than 254 nm, with significantly less DNA damage to mammalian cells.
For devices operating not point-wise between dispatches, but continuously – throughout the entire shift, in the presence of paramedics – the market uses the concept of Continuous Active Disinfection (CAD). This is a real, research-confirmed difference, but it does not mean unconditional safety. Permissible occupational exposure limits still apply, and most of the safety data for Far-UVC comes from the last few years. Models with filters limiting radiation outside the 222 nm band, while adhering to the manufacturer’s limits, are a good choice for CAD systems – the “safe for humans” label is not an exemption from any exposure limits. A system constantly operating in the presence of paramedics should have documented daily exposure parameters, not just a general safety declaration.
Real example: reducing vehicle downtime
The scale provided by UV technologies is well illustrated by an example from the Emergency Medical Service in Jelenia Góra. Ambulances there were disinfected using the VireWall Soluva Zone H device – a mobile UV sterilizer operating dry, without chemicals and moisture. The full cycle of vehicle disinfection took about 30 minutes.
What distinguishes this example from most marketing materials is the verification method. Samples from the same places in the ambulance were taken before and after the treatment, and the results went to the independent microbiological laboratory of the Voivodeship Hospital Center of the Jelenia Góra Valley – not to the quality department of the device manufacturer itself.
It is the reduction of downtime, not the biocidal efficacy itself, that is the main business argument for UV technologies in ambulances – classic chemical disinfection with drying and airing time is simply sometimes slower than required by an emergency medical system operating under the pressure of subsequent dispatches.
Plasma disinfection and fogging – other post-pandemic technologies
Besides ozone and UV, there are low-temperature plasma generators on the market, producing biocidal reactive oxygen and nitrogen species, and foggers spraying a fine droplet aerosol of a disinfectant – most often based on hypochlorous acid (HOCl), a compound with low toxicity to humans in the concentrations used. Fogging is currently probably the most widely used of the methods described here in Polish ambulances – low entry cost, no need for specialized training of personnel.
Plasma as a rescue vehicle disinfection technology is still relatively new – there is less available data on its application specifically in ambulances than for ozone or UV. The mechanism differs in that the device generates a broad spectrum of reactive oxygen and nitrogen species simultaneously, not just a single chemical compound, which in theory makes it harder for microorganisms to develop resistance to a single mechanism of action. In practice, this technology is currently better documented in industrial and food applications than in rescue vehicles. For ambulances, this is not a dealbreaker, but rather a signal to approach the manufacturer’s assurances with greater caution and demand independent microbiological test results.
Foggers based on hypochlorous acid generate the solution most often by the method of water electrolysis with a small addition of salt, and the preparation itself decomposes back into water and salt over time – hence the low toxicity compared to traditional chlorine or alcohol-based agents. Important reservation: the PN-EN 14476+A2:2019-08 and PN-EN 16777:2019-01 standards certify the disinfection preparation itself. The fogger as a device is only a carrier for this preparation, so its biocidal efficacy must be assessed by the certificate of the specific agent, not by the equipment itself.
| Method | Operating principle | Does it require emptying the vehicle | Main limitation |
| Ozonation | Oxidation of cell membranes and viral envelopes | Yes | Toxicity, risk to rubber and plastics with frequent use |
| UV-C 254 nm | Damage to microorganism DNA/RNA | Yes | Harmful to skin and eyes |
| UV 222 nm (Far-UVC) | Damage to DNA/RNA, absorbed in the dead skin layer | Usually not, within dose limits | Shorter history of safety data in vehicles |
| Low-temperature plasma | Reactive oxygen and nitrogen species | Depends on the device | Little data specific to ambulances |
| Fogging (e.g., HOCl) | Aerosol of a chemical agent | Usually yes, for the time the fog settles | Requires an agent certified according to PN-EN 14476/16777 |
What physical methods will not replace
None of the described technologies replaces the manual removal of visible biological contamination, such as blood or vomit – the effectiveness of ozone, UV, and plasma drops sharply in the presence of organic matter, which shields microorganisms from radiation or an oxidant. Therefore, the sequence must always look the same:
- mechanical cleaning of visible biological contamination;
- only then physical or chemical disinfection – as a supplement to the procedure, never as its replacement.
It is also worth distinguishing what the applicable standards refer to. The PN-EN 14476+A2:2019-08 and PN-EN 16777:2019-01 standards, confirmed by the National Institute of Public Health NIH – National Research Institute as suitable for assessing virucidal efficacy against SARS-CoV-2, certify chemical disinfectants – liquids, gels, fogging preparations. They do not cover UV lamps, ozone generators, or plasma devices. Therefore, the manufacturer of a physical disinfection device cannot cite compliance with EN 14476 as proof of effectiveness. It is simply a different product category.
How to assess the real effectiveness of a device before purchase
Since a standard virucidal certificate does not apply to physical devices, it is worth looking for proof of a different kind when buying: independent microbiological tests using the swab method, performed before and after the treatment in conditions close to real ones, preferably by an external laboratory. This is exactly how the action in Jelenia Góra was documented. This is a model worth repeating as part of your purchasing procedure.
Declarations like “100% elimination of pathogens” should be treated with distrust. Biocidal efficacy depends on the species of the microorganism, concentration, exposure time, and surface condition, so a generalized number without indicating the method and test conditions is not reliable.
Before signing a contract with a supplier, it is worth asking a few specific questions, regardless of which of the described technologies is being considered:
- Do the microbiological test results come from an independent laboratory, or exclusively from the manufacturer’s quality department?
- Were the tests conducted in conditions similar to the interior of an ambulance, or in a larger test room?
- What specific microorganisms or viruses were tested and by what method – swab, culture, other?
- What is the actual time of a full cycle in the tight interior of the vehicle, and not the declared time in laboratory conditions?
- What are the documented exposure limits for personnel when the device is operating in continuous mode?
- How does the use of the device affect the warranty of the medical equipment installed in the vehicle?
A lack of specific answers to these questions usually signals that the supplier’s offer is based primarily on marketing materials.
What to consider when designing ambulance equipment in terms of future disinfection technologies
Regardless of the chosen technology, its effectiveness largely depends on the vehicle’s interior itself. Smooth, sealed surfaces without unnecessary connectors and crevices limit the places where microorganisms can accumulate out of reach of radiation or aerosol.
The requirement for easy-to-disinfect interior materials, which KG Special Performance described earlier in the context of new technologies in ambulance superstructures, already applies today to every manufacturer of medical superstructures in accordance with the EN 1789:2020+A1:2024 standard – regardless of what disinfection technology the end user of the vehicle chooses. Anyone planning to implement UV, ozone, or plasma in the future should check the full requirements of the EN 1789 standard for a medical vehicle already at the stage of purchasing an ambulance – from materials to equipment placement.
The cost of maintaining the chosen technology throughout the vehicle’s life cycle deserves attention already at the purchasing stage, not only after a year of operation. It usually includes:
- regular replacement of UV lamps;
- cleaning the ozone generator plates;
- periodic calibration of sensors and control systems.
Skipping this stage is a common reason why equipment stops working according to the declared parameters after a year of operation.
FAQ
Ozonation itself is safe only when the vehicle is completely empty during the treatment and thoroughly aired out after its completion – in biocidally effective concentrations, ozone is toxic to the respiratory tract. Personnel and patients should not enter the ambulance before the airing time recommended by the device manufacturer has elapsed.
It depends on the device and the wavelength. The example from Jelenia Góra shows a full cycle of around 30 minutes, verified by independent microbiological tests.
No – both technologies lose effectiveness in the presence of visible biological contamination, which is why they are always preceded by manual cleaning.
UV-C 254 nm effectively destroys microorganisms but is harmful to skin and eyes, so it requires an empty room. UV 222 nm (Far-UVC) works on a similar principle but is absorbed already in the dead, outer layers of skin and cornea – studies indicate a significantly lower risk to humans while maintaining permissible exposure doses, although data on long-term safety in vehicles is still relatively fresh.
It depends on the specific device and the manufacturer’s declaration – this is a relatively new technology in the context of rescue vehicles, generating reactive oxygen and nitrogen species instead of a single chemical compound. Before purchasing, it is worth demanding independent test results rather than relying exclusively on promotional materials.
