Explore the Possibility of Disinfection Tunnels with No Harm to Humans

Recently, disinfection tunnels have started gaining traction as a solution for sanitizing goods and people during the COVID-19 pandemic. However, while new models continue to emerge on the market, people are understandably concerned by the concept of being sprayed with potentially hazardous chemicals. Below is a critical look at the safety of a sanitizer tunnel for human use.

Disinfection Tunnels: Principles of Operation

At its core, a disinfection tunnel is a passageway outfitted with nozzles that spray a sanitizing agent in the form of fine mist. The microscopic size of the particles makes the mist completely dry (hence the name of the procedure — dry fogging) and allows them to disperse evenly on surfaces. Some disinfection tunnel manufacturers also outfit their tunnels with additional sanitation measures, such as UV lamps or ozone generators. The size of the tunnel may vary depending on the area of application, with models for humans usually large enough for one person to comfortably pass through.

Chemicals Used in Disinfection Tunnels

When it comes to the safety of the sanitizer tunnel for human use, the main culprit is the solution used for disinfection. The reason for this is clear: disinfection tunnel efficacy against microorganisms suggests that the chemical may be equally deadly to other forms of life. Fortunately, this is not necessarily the case. Currently, several disinfectants are available on the market:

• Hypochlorous Acid
• Alcohol
• Sodium Hypochlorite
• Hydrogen Peroxide

While some are known to be hazardous for humans, others are completely safe for anything other than microorganisms.

Sodium Hypochlorite

Early in the course of the COVID-19 outbreaks, disinfection tunnels in China and India were using sodium hypochlorite as a public safety measure. It is the same compound that is used in bleach — a household chemical and a powerful disinfectant. The obvious drawback here is that bleach is exceptionally hazardous for any life form, including humans. The main argument is that when applied in the right concentration, it can be used on people without posing health risks. However, even when diluted, it can cause skin, eye, and mouth irritation. In other words, this is clearly a harmful solution not suitable for use on people.

Hypochlorous Acid

Due to concerns voiced by health organizations, sodium hypochlorite is being discontinued as a sanitizing solution in disinfection equipment in favor of safer options. From the perspective of a disinfection tunnel for COVID 19 manufacturer, the most feasible alternative is a chemically selective compound. This chemical would work only on microorganisms while not affecting more complex life forms. One such compound is hypochlorous acid.

Also known under commercial names like EnviroNize, electrolyzed water, or super-oxidized water, hypochlorous acid is a food-grade product and has been successfully used for water treatment, and sanitation of food preparation surfaces long before the outbreak. On top of that, it causes no irritation and leaves no residue, which makes it particularly suitable for daily usage in public spaces. The chemical has also been approved for use in schools by Health Canada, which gives a basic idea of whether using it in a sanitizer tunnel is safe or not. To sum up, it is perhaps the safest option currently available on the market.

Alcohol

Ethanol and isopropyl, collectively referred to as alcohol, is another popular solution for disinfection. Because it does not irritate the skin, it is recommended by the CDC both for hand hygiene and household cleaning. However, its application in disinfection tunnels is limited. First, it does irritate mucous membranes, which would affect the eyes, nose, and mouth of users. Second, it is volatile, which becomes an issue for fine particles of the dry fog. In other words, while it can be considered safe for humans, alcohol is not an optimal solution for disinfection tunnels.

Hydrogen Peroxide

Hydrogen peroxide is another substance that can be used as a sanitizer against COVID-19. However, while health authorities list it as safe, it has several disadvantages. For starters, it is known to have several adverse health effects. It can also have a corrosive effect in specific concentrations, rendering it unsuitable for many applications. Finally, it is unclear whether low concentrations that are safe for human skin are effective against SARS-CoV-2. In other words, the efficacy of hydrogen peroxide in disinfection tunnels is questionable.

Disinfection Tunnels Advantages and Disadvantages

While chemicals used for spraying are a vital aspect of the safety of sanitizer tunnel for human, the concerns do not end there. There are many other factors that can make a disinfection passage safe (or hazardous) for the public. Here is a brief overview.

Advantages

• Highly autonomous: Disinfection tunnels are designed to operate automatically with little to no involvement of human operators, making them both efficient and safe.
• Additional monitoring measures: Newer models are equipped with thermometers, which can prevent sick people from entering.
• Encourage safe behavior: Mask recognition sensors can be used for tighter security and promote the culture of safety.

Disadvantages

• Only disinfect surfaces: A sick person will still be a source of infection after passing through the sanitation passage.
• A false sense of safety: May encourage unsafe behavior (e.g. not wearing a mask) after being sanitized.

As can be seen, the tunnels are safe from the operational standpoint as long as an appropriate chemical is used. However, they can still pose a risk when used without a proper understanding of the technology. In other words, disinfection tunnels need to be a part of the prevention strategy to realize their potential fully.

Wrapping Up: Are Disinfection Tunnels Good or Bad?

Overall, there is nothing inherently unsafe about disinfection tunnels. From the design perspective, they pose no risks to human health as long as an appropriate sanitizer is used. Understandably, they have their limitations and may actually be counterproductive when used outside their intended purpose or without explicit instructions. Nevertheless, they remain one of the safest multi-purpose disinfection options for public spaces.