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I am dreaming of the day that every doctor knows what a CO2 meter is, how to use it, and can teach their patients about the benefits of fresh air to help stop COVID-19 transmission.
Yes, this is a very useful technique, although it has some limitations. Outdoor CO2 is about 400 ppm, and human exhaled breath contains about 40000 ppm of CO2. Thus adding exhaled air to an indoor space rapidly increases the CO2 concentration. @jljcolorado tutorial
Since accurate, affordable CO2 meters are available, measuring CO2 is the best way to get a sense of the amount of exhaled air in a space. If you measure:
~400-500 ppm, the level of ventilation is very good
~400-500 ppm, the level of ventilation is very good
~800 ppm, 1% of the air you are breathing has already been breathed by someone in the space. This can start to be risky.
~4400 ppm, 10% of the air you are breathing has already been breathed by someone else. This is a very dangerous situation.
~4400 ppm, 10% of the air you are breathing has already been breathed by someone else. This is a very dangerous situation.
In well ventilated spaces, CO2 should stay below about 700 ppm to reduce COVID-19 infection risk. CO2 can be monitored with an affordable (~$150) meter as described below, which can be easily shared with many people.
more... https://docs.google.com/document/d/1fB5pysccOHvxphpTmCG_TGdytavMmc1cUumn8m0pwzo/edit#
more... https://docs.google.com/document/d/1fB5pysccOHvxphpTmCG_TGdytavMmc1cUumn8m0pwzo/edit#
Here is a chart to show how masks, voice projection, and ventilation influence Covid19 risk. #CovidRiskChart from @trishgreenhalgh
