Instructions

AIR QUALITY AND ECO2
The Air Quality Sensor board uses a sensor with a part number of CCS811. This
small chip does not actually measure the level of CO2 (carbon dioxide) but instead
the level of a group of gasses called volatile organic compounds (VOCs). When
indoors, the level of these gasses rises at a fairly similar rate to that of CO2, and
can therefore be used to estimate the level of CO2 (called the equivalent CO2 or
eCO2).
The level of CO2 in the air we breathe has a direct influence on our well-being. CO2
levels are of particular interest from a public health point of view as, to put it simply,
they are a measure of how much we are breathing other people's air. We humans
breathe out CO2 and so, if several people are in a poorly ventilated room, the level
of CO2 will gradually increase. This is much the same as the viral aerosols that
spread colds, flus and Coronavirus as people breathe both out together.
Another important impact of CO2 levels is in cognitive function – how well you can
think. This study (amongst many more) have some interesting findings. The
following quote is from the National Centre for Biotechnology Information in the
USA:
“at 1,000 ppm CO2, moderate and statistically significant decrements occurred in
six of nine scales of decision-making performance. At 2,500 ppm, large and
statistically significant reductions occurred in seven scales of decision-making
performance” Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3548274/
The table below is based on information from https://www.kane.co.uk/knowledge-centre/what-
are-safe-levels-of-co-and-co2-in-rooms and shows the levels at which CO2 can become
unhealthy. The CO2 readings are in ppm (parts per million).
Level of CO2 (ppm) Notes
250-400 Normal concentration in ambient air.
400-1000 Concentrations typical of occupied indoor spaces with good
air exchange.
1000-2000 Complaints of drowsiness and poor air.
2000-5000 Headaches, sleepiness and stagnant, stale, stuffy air. Poor
concentration, loss of attention, increased heart rate and
slight nausea may also be present.
5000 Workplace exposure limit in most countries.
>40000 Exposure may lead to serious oxygen deprivation resulting
in permanent brain damage, coma, even death.
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