CO or CO2, both are products of combustion, CO has a lot more impact at lower concentrations than CO2.

Breathing would be CO2, but surely the offices are not so well sealed that you are not getting enough air changes?

That would be my first port of call is to see what the natural ventilation and air changes are.

I don’t see what machinery creates CO2, apart from combustion appliances, laser printers and photocopiers IIRC are Ozone producers, not CO2.

Quick bit of research as this sounded like a heresay reveals

EH40 lists a WEL for CO2 at 5,000 ppm TWA / 15,000 ppm STEL and falls under COSHH http://www.hse.gov.uk/carboncapture/carbondioxide.htm

There are also many articles citing that normally an office will be @ 1,000 ppm but that productivity starts to decline once levels raise above 2,000 ppm

Then you spot a report on a more recent piece of research and draw a conclusion to bananana plants aiding a better nights sleep https://www.theguardian.com/environment/2019/jul/08/indoor-carbon-dioxide-levels-could-be-a-health-hazard-scientists-warn

after coffee correction 15-18% CO2 in exhaled breath..

Originally Posted by: stevedm

EH40 deals with 100% CO2....

Air Liquide list 1.832Kg of Carbon Dioxide giving a volume of one cubic metre at 21C & 1 atmosphere - or 204 times the WEL

http://www.hse.gov.uk/carboncapture/carbondioxide.htm

According to the HSE (who might know thing or two) carbon dioxide exists in the normal atmosphere at a level of about 0.037%, which is 370 ppm. According to EH40 the Long-term exposure limit (8-hr reference period) is 5000 ppm. This is averaged over an eight hour shift so the level can be safely over 5000 ppm for short periods. The short-term exposure limit (15 minute reference period) is 15000 ppm. In effect this means that the level should never go above this number.  So to be hazardous the level of carbon dioxide would need to go over 30 times the normal level.  Such an increase would occur (according to the HSE) in confined spaces such as tanks, sumps or cellars. It is also possible for CO2 to accumulate in trenches or depressions outside following leaks and this is more likely to occur following a pressurised release where the released CO2 is colder than the surrounding air.  This is all as the result of a sudden release of pure gas, for example in a brewery. It is difficult to image a scenario where people in an office could generate so much CO2, simply through normal respiration even if the room was totally air tight.