Saturday, February 27, 2021

Staying Safe from COVID by Measuring the CO2 in the Air

So, you might be saying to yourself, Huh? What does CO2 have to do with COVID-19?

Linsey Marr is a professor at Virginia Tech and an expert on virus aerosol transmission. She and a growing number of scientists believe measuring CO2 could be a good tool to use in shared spaces as a way to defend yourself from getting COVID-19.

As you may know, the coronavirus that causes COVID-19 is an airborne virus. People can be infected through exposure to virus-containing droplets which are suspended in the air. The closer you are to others and the longer you spend in the same room with them, the greater the risk you will inhale some of those droplets.

Carbon dioxide is what we exhale when we breathe, and it’s all around us.

When you walk into a supermarket or a restaurant, you have no idea how good their ventilation system is in clearing COVID-19 out of the air. Measuring the carbon dioxide in a room can serve as a proxy for how well their ventilation is working. 

According to Marr if you’re in a poorly ventilated room, the amount of carbon dioxide will build. If you add more people in the room the levels will keep rising. But when you crack open a door or window, or put a fan in the window, you will be bringing in outdoor air and help remove some of the accumulated CO2.

When you are outdoors, carbon dioxide levels in the air usually hovers around 400 parts per million. When you are indoors, if the CO2 in the room gets up to 800 ppm it means with every breath you take, 1% of the air you breathe in was exhaled by someone else. 

With a good CO2 sensor, experts say you should aim to keep CO2 levels between about 400 and 800 ppm. They want it below 600 for spots such as a gym, where people are breathing heavily.

A 2019 study was conducted during a tuberculosis outbreak in Taiwan which highlights the difference CO2 levels can make. The researchers discovered that some poorly ventilated rooms had CO2 levels that were above 3,000 ppm; when they lowered the level to under 600, the outbreak stopped.

Using CO2 sensors in public establishments as well as schools and churches and posting their results would allow them all to be more certain about their being able to open safely. Investing in a portable CO2 sensor for yourself would also put you in charge of being able to measure the level where you were in order to decide to stay or go.

Marr recommends that you use a nondispersive infrared sensor. And she also recommends that sensors should still be used in conjunction with wearing face masks, continuing to do physical distancing and hand washing.

So, keep in mind that the life you save by investing in a CO2 sensor may be your own or a loved one!
(Reported The Virginian-Pilot, February 18, 2021) 

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