Disinfectant tunnels: the simple-wrong solution

One of my professors use to say, complex problems often have many simple but wrong solutions, More the complexity, more numerous the simple-wrong solutions. COVID19 is a very, very complex problem... Imagine how many simple-wrong solutions it may have. Is the disinfectant tunnel, one of the recent, much-celebrated specimens of "Indian Jugaad", one of these simple-wrong solutions?

My curiosity about the tunnels was triggered by a recent discussion with a friend who is an Angel investor. He argued why he will never invest in any startup making such tunnels. So I decided to understand a little more about it using Google. Given that I am not an expert on public health issues like these, what I am writing here is just a summary of several google searches I ran about the topic.

To start with here is an obvious question to ask:

If these tunnels work, why isn't every country using them?

The same question may be asked in the context of cow urine too... but that one has many simple-wrong-hard-to-argue answers. So I don't dare delve in those debates.

Such tunnels were first used in China, the epicenter of the COVID-19 outbreak. In fact, China, which does not believe in small scale, sprayed entire cities with disinfectants. They even made awesome videos of giant sprayers and shared them on social media portals that do not work in their country. But there have been several questions about the effectiveness of these measures.

These concerns should be enough to raise caution against going on a spending spree to acquire the tunnels in hundreds and installing them in public spaces, the enthusiasm many state governments share.

But lets for a minute believe that the rest of the world is jealous of this Chinese invention turned precious Indian "Jugaad", and that's why they are abstaining from it. Let us ask a few questions about the effectiveness and/or hazards of these tunnels.

Are these tunnels effective?

The disinfection tunnels do not kill any virus already present in your nose, throat or body, hence a person infected with COVID-19 will remain infectious even after passing through the tunnel (WHO Mythbusters). For those who are not infected, these tunnels are at best meant to supplement the recommended measures, Washing hands, Wearing masks, Social distancing, etc. So even if they work, they are rather a "good to have" rather than a "need to have" solution.

What is this magic spray?

Quoting this news article

Essentially these tunnels spray a mist of sodium hypochlorite solution, a chlorine compound often used as a disinfectant or a bleaching agent, as you pass through them. Sodium hypochlorite is a component of commercial bleaches and cleaning solutions and used as a disinfectant in drinking and wastewater purification systems and swimming pools.

So that sounds about right. but Are these tunnels safe for living beings?

Here is where they do not particularly shine. This infographic from W.H.O should give us a clue as to why.

https://www.who.int/emergencies/diseases/novel-coronavirus-2019/advice-for-public/myth-busters

Most of the articles about the spray tag it from not-safe to hazardous in the form of mist. exposer to sodium hypochlorite by inhalation of aerosols (like the disinfectant mist) is widely advised against. The compound is irritant to the lungs and causes coughing and sour throat. For people with respiratory problems, it may be even more dangerous. Multiple exposures of this mist can seriously compromise the immunity of a healthy being. More importantly, a slight variation in the concentration of sodium hypochlorite could lead to mild to extremely serious side-effects, ranging from skin and eye irritation to severe burns. Some tunnels spray ethanol instead of sodium hypochlorite, which is milder but has its own side effects like dehydration.

In summary, these spray tunnels are neither conclusively effective nor safe to be used on living beings. The sanitization compounds they spray, must not be used on humans in the form of mist or aerosols. If at all such tunnels are to be used, they must be used with extreme caution and effective face and eye masks.

It is good that some states, like Punjab, TamilNadu, JandK, UP, have understood this and decided to rid themselves of these tunnels.

But while these states are exercising caution, in other parts of the country, the "Jugaad" has reached the next level, Telangana and Kerala have invented Sanitizing Buses and even railway coaches to fog people in masses.

Human trials of a COVID19 vaccine are about to start, And yet any vaccine or cure of COVID19 is at least 12 months away, even when it is so direly desired right now. The reason for such delay is that the scientific community is acutely aware of the hazards of the simple-wrong solutions. The general public and Administration too should pursue solutions to this complex problem with some if not the same scientific rigor.

While Jugaad can give us some bright ideas, they must be vetted well before mass adoption. After all, two wrongs hardly ever make it right.