In an effort to bring attention to how much 'recycled' air we are breathing, Farah Hancock took a portable CO2 monitor to a range of commonly frequented locations to read localised CO2 levels. CO2 levels are currently our best way of indicating the risk of catching COVID-19 as they represent recently exhaled or 'recycled' air from other patrons.
Ambient CO2 levels normally sit at around 420ppm, with anything under 800ppm (parts per million) considered a good level. 800 - 1000ppm is acceptable, but efforts should be taken to reduce levels to under 800. 1000 - 2000ppm starts to see people experiencing headaches and should be avoided whenever possible. Anything above 2000ppm is an exceptionally high concentration.
Dr Joel Rindelaub from New Zealand's University of Auckland said that higher CO2 levels can be indicative of the expelled respiratory particles in the air. These particles can spread COVID-19 among other viruses, so monitoring CO2 can give us good insights into the likelihood of catching COVID-19 in specific areas.
In order to discover the risks of specific locations, Farah Hancock took a portable monitor to locations where we often spend large portions of our lives. At schools, she found a top reading of 1373ppm, far above the 800ppm benchmark for good air quality.
In cafes and shops, readings were 663ppm and 980ppm, respectively. While neither of these readings is exceptionally bad, it shows that even shops commonly exceed the guidelines for 'safe' levels of CO2.
However, the true discovery comes in the form of high-risk locations. Bars showed a parts per million reading of 2624, gyms were as high as 4288ppm, taxis sat at 3653 but were seen to go as high as 5040ppm, and public transport saw record highs of 5737ppm. This reading indicates that one in every seven breaths is effectively 'backwash'.
It also highlights the importance of wearing masks in these situations. While masks can't filter out CO2, they can filter out the respiratory particles that come alongside it. This is truer than ever in a gym, bar, taxi, or public transport.
Want to read about further findings? You can find the full article here.