Ambient CO2 concentration in the atmosphere now exceeds 400ppm and levels of 1,000ppm can cause drowsiness and lethargy. The level of 1,000ppm and is a guideline for maximum levels from the World Health Organization.
GSS took a battery-operated CO2 datalogger to Asia and logged CO2 levels on planes, trains and automobiles. "We were surprised that levels were the worst in taxis – peaking at an astonishing 10,000 ppm on one journey – so we decided to check the levels on our own road trip in the UK," said David Moodie, technical manager at GSS, in a statement.
Plot of CO2 concentration in car used by two people for journeys on sequential days. Source: GSS Ltd.
With four people in a stationary vehicle cabin and the windows closed the CO2 level went from 1,000ppm initially to 4,000pm in 15 minutes.
With two people in a car it took 45 minutes to get to 1,400ppm and took many hours to reduce to near ambient levels when the car was left unoccupied overnight.
The data shows that CO2 concentrations can easily reach 2,000pm, where loss of concentration, headaches and sleepiness can result. Fortunately high CO2 levels are signalled by a stuff unpleasant atmostphere that usually prompts vehicle occupants to open a window or change the cabin air using comfort controls.
Moodie said: "Our real-world datalogger measurements show how CO2 levels can rapidly build up in an enclosed space with several occupants – and in a relatively short space of time too. The results on both journeys exceeded The World Health Organisation guideline that CO2 levels should be below 1000 ppm."
GSS battery operated datalogger. Source: GSS Ltd.
The datalogger used in the experiment measures CO2 concentration, air pressure and temperature, along with relative humidity every few minutes and is based on one of the CozIR sensors from GSS. The low power consumption of the sensor enables battery operation for a two-week period.
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