What does CO₂ have to do with Covid?

Learn what CO2 has to do with Covid and how measuring the concentration of CO2 in the environment can help reduce the likelihood of contagion.

By now, everyone knows that there is a link between CO2 and Covid because of the many times it has been discussed in the media, but many people do not know exactly what this relationship is.

This article was part of the introduction of the tutorial for the construction of the homemade CO2 meter but the article was already getting to be a huge length, so I have decided to separate this part and keep it in its own space. independent.

What does CO₂ (Carbon Dioxide) have to do with Covid-19?

Absolutely nothing. However, these two words together are on the lips of many experts in the health and scientific community. Why? Read on...

The CO₂ is a gas dangerous to humans. In high concentrations it can cause ailments such as dizziness, headaches, increased blood pressure, accelerated heart rate, and in severe cases can lead to asphyxia and unconsciousness.

We have been talking and hearing about the Coronavirus all the time for months now, perhaps too much for our mental healthI am not going to comment on it. Everything I can say about the Coronavirus, you probably already know.

We simply have to remember that, at present, the best way to prevent Covid is to protect against the SARS-CoV-2 coronavirus. and this is achieved through fairly basic, almost hygienic practices. And at the heart of all this is that he who avoids the occasion avoids the danger.

⚠️ The air we breathe and Covid

Although CO₂ has no direct link to Covidyes, I do there is a very important indirect relationship and, that is, the quality of the air we breathe, and the viral load that this air may have.

When there are several people in a room and one of them is a carrier of the virus, the virus will is suspended in the air for a variable time, at the expense of the other people sharing the room being able to breathe it in and out, and catch. These are the famous aerosolsWe have been hearing so much about them lately.

The more time passes, the more the viral load in the air increases, so the more the airborne virus load increases. increasing the danger of other people becoming infected.

For this reason, adequate renewal of the air in the room is essentialand this is achieved by ventilating.

In working environments it is more or less common to have forced air systems that facilitate ventilation and air exchange (and even filtering through HEPA filters) but this is very rare in private homes, where the only option is often to ventilate by opening the windows..

The problem is that the virus is invisible, we can't look at the air and see the viral load in it to decide to ventilate when we see that it is necessary. This is where the CO₂ meter comes into play.

As the Consejo Superior de Investigaciones Científicas (Spanish National Research Council) (CSIC), in its guidance on reducing the risk of contagionCO₂ measurements are one of the best ways to check that we are maintaining adequate ventilation:

The CO₂ (carbon dioxide) is a gas that we naturally expel when we breatheThe concentration of this gas in the environment can give us an idea of how much of this gas is present in the environment.uploaded"the air in that room is, what is allows us to decide when it is time to ventilate and for how long to do so.

In other words, knowing the concentration of CO2 allows us to know the "second-hand air we are breathing.

This is especially important in winter, because, due to the low temperatures, we tend to ventilate much lessdelaying the time to open the windows.

As he says on Twitter the Spanish professor and scientist, from the University of Colorado, José Luis Jiménezone of the world's leading authorities on aerosol-borne transmission of COVID-19, echoed Dr. Holte's words:

ℹ In the opinion of José Luis Jimenez, "at least 75% of the contagion and probably up to 90%" is due to aerosols..

CO₂ figures in the air

CO₂ is naturally present in the air. in an approximate proportion of 415 ppm (415 parts per million, or in other words 415 parts of CO2 per million parts of air).

The trick is to monitor how many parts per million of CO₂ and maintain adequate ventilation to ensure that this number does not reach a certain figure.which we consider too high.

In the following table, created by CoviBlock, you can see how much of the air you breathe is already in the air you breathe. has been previously breathed by another personmeasuring the level of CO2.

And what is this magic number, or from how many parts per million of CO₂ do we have to ventilate?

There is no magic number, but we can use some standards to help us understand when the number is too high. The maximum CO₂ concentration recommended by the WHO for healthy environments is 1000 ppm. As a general rule, a concentration of CO₂ below 800 ppm is considered adequate.but ideally closer to 500 ppm.

I leave you with the following infographic by Sergio Coscolin (@SergioCoscolin), who explains it very well and I would like to take this opportunity to thank him for his magnificent informative contributions, in the form of infographics?

RITE regulations in educational centres

To get an idea of what the air quality standards say, we can take the regulations for schools as an example.

In Spain the main regulatory framework on indoor air quality is the Regulation on Thermal Installations in Buildings (RITE)which classifies air quality into 4 categories: IDA 1, IDA 2, IDA 3 and IDA 4 (indoor air).

• TEACHING CLASSROOMS category IDA 2 (good quality air) is required, to which RITE assigns a limit value of +500 ppm on the concentration of CO₂ from outside. 
• The requirement is increased to IDA 1 (optimum air quality) to which RITE assigns a limit value of +350 ppm on the concentration of CO₂ outside. 

In these COVID timesmost of the experts worldwide seems to recommend that CO₂ concentration figures in educational classrooms, and in places such as offices, shops, hairdressing salons, etc., should be kept to a minimum. below about 700 ppmto ensure sufficient aeration.

Examples and actual figures of CO₂ concentrations in a house

In order to better understand where these CO₂ values are moving, I am going to show you as an example my own home.

This graph corresponds to the CO₂ concentration in the living room of my house on a Saturday in November (all closed up tight because of the cold), completely ignoring the data of CO₂ (as I think they would in any normal household).

What can we see in this graph?

Basically that CO₂ levels are very high, and which remain above WHO-recommended values almost all day long.

• Although CO₂ values drop to around 450 ppm when the room is ventilated at around 14:00h for about half an hour, the lack of air renewal causes the values to rise again rapidly, reaching a worrying 2300 ppm.
• On this day, all five members of the family (and the dog) watched a film on the projector in the living room, which explains the noticeable increase in CO₂ in the afternoon.
• It is clear that the CO₂ has risen rapidly since 15:00 (when we all met for lunch).

As you can see, the air quality in this salon leaves a lot to be desired..

The data in the salon are taken with a Netatmo weather stationwhich has an indoor CO₂ sensor.

The situation can be much worse. Look at the following graph with the data recorded on a typical night in October, in a typical bedroom occupied by two people and a dog medium:

CO2 concentration reaches up to 3921 ppm!

In the following graph you can see CO2 data from my cave (my room in tinkering):

This data is updated in real timeIf you look at it for a while, you'll see how every minuteIn about , a new measure appears.

In the tutorial to build the homemade CO2 meter I show you how you can create a graph like this one, easy and completelynte free of charge.

A home CO2 meter with Wifi against the coronavirus: The CO2 Easy

What do I have to do to maintain good air quality?

The most important thing is ventilationThis small action, which we have not paid much attention to for many years and which, fortunately, is becoming more and more of a topic of conversation in bars, raising awareness among all kinds of people.

Instead of leaving you here an endless rambling, I'm going to leave you the following infographic by Sergio Coscolin (@SergioCoscolin), which explains it very well.

What if I want to buy a ready-made CO2 meter?

If, for whatever reason, you do not want to build your own home CO2 meter, you have the option of buying a commercial one. Plug and play.

There are many models on the market, but, I must warn you that many of them are absolutely worthlessThe reason for this is that they have a type of sensor that is affected by all kinds of gases and the meter is not able to distinguish CO2 from any other gas (and there are many gases in the air that come and go, so you will never know whether it is measuring CO2 or something else).

Whichever meter you buy, I recommend that you buy one with an NDIR sensor. (and bear in mind that, if it doesn't say so, it probably doesn't carry it).

If you want a commercial meter that is inexpensive and works wellI would suggest one of these two options:

No products found.

I have this one below which is very similar, but with a few additional things that make it a weather station:

If you want to see more models available at good prices, the best sellers, best offers, etc. you have the option to visit this site CO2 meter buying guide.

Why should I measure CO2 to avoid Covid infection?

OK, just to be clear: Measuring CO2 levels in indoor spaces is not directly related to the prevention of coronavirus transmission. However, measuring CO2 levels can help determine the effectiveness of ventilation systems in rooms or buildings, which can help reduce the spread of the virus.

CO2 is a by-product of human respiration and can serve as an indicator of how well or poorly a space is ventilated. High levels of CO2 can indicate poor air exchange, which could lead to the build-up of other contaminants, including the virus that causes COVID-19. By monitoring CO2 levels, we can ensure that ventilation systems are working properly and that the air inside a building is being cooled at a sufficient rate to reduce the concentration of the virus.

It is important to note that CO2 monitoring alone is not sufficient to prevent transmission of the coronavirus, other actions such as the use of masks, social distancing and frequent cleaning and disinfection are also necessary.