Late nights, a stodgy lunch – there are many reasons for the dreaded mid-afternoon energy slump.
But rest assured it might not be all your fault.
U.S. scientists have found that high levels of carbon dioxide in offices and classrooms could be affecting our concentration and decision-making abilities.
High levels of carbon dioxide in offices and classrooms could be affecting our concentration and decisions
The primary source of indoor carbon dioxide is humans. While typical outdoor concentrations are around 380 parts per million (ppm), indoor concentrations can go up to several thousand ppm.
Higher levels indoors are usually due to poor ventilation, often a result of the need to reduce a building’s energy consumption, the researchers say.
The research was conducted by scientists at the State University of New York and the Lawrence Berkeley National Laboratory at the University of California.
They found that carbon dioxide concentrations in office buildings normally don’t exceed 1,000 ppm, except in meeting rooms, when groups of people gather for extended periods of time. (Which may partly explain why it’s so hard to stay awake in meetings.)
In classrooms, concentrations frequently exceed 1,000 ppm and occasionally exceed 3,000 ppm.
While these levels weren’t found to be dangerous to health, they did significantly impair people’s ability to think or make decisions.
The researchers say even they were surprised by the results, which are the first to make a link between high levels of carbon dioxide and a decline in work performance.
‘In our field we have always had a dogma that carbon dioxide, at the levels we find in buildings, is just not important and doesn’t have any direct impact on people,’ said study co-author and Berkeley scientist William Fisk. ‘So these results, which were quite unambiguous, were surprising.’
At carbon dioxide levels of 1,000 ppm – a fairly typical level for an office – volunteers showed a dramatic decline in performance in six out of nine tests. It became significantly worse when the level rose to 2,500ppm.
‘Previous studies have looked at 10,000 ppm and 20,000 ppm; that's the level at which scientists thought effects started,’ added Dr Fisk's colleague and co-author Mark Mendell. 'That's why these findings are so startling.'
Classrooms were found to have particularly high levels of carbon dioxide due to the volume of people, prompting fears that exam performance could be affected
Although their study only tested decision making and not learning, the researchers say it’s possible that students in poorly ventilated classrooms - or rooms in which a large number of people are gathered to take a test - could also be at a disadvantage.
And while the results need to be replicated in a larger study, they point to possible economic consequences of energy-efficient buildings.
‘As there’s a drive for increasing energy efficiency, there’s a push for making buildings tighter and less expensive to run,’ said Dr Mendell.
‘There’s some risk that, in that process, adverse effects on occupants will be ignored. If people can’t think or perform as well, that could obviously have adverse economic impacts.'
The study was published in the journal Environmental Health Perspectives.
Read more: http://www.dailymail.co.uk/health/article-2220218/Why-office-sending-sleep.html#ixzz29yejrSEe
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