Thought leadership: CO2 air quality

air case study


How to ensure your building doesn’t undermine your organisation’s performance

It’s not just London’s roadsides where air quality is a cause for concern; indoor air quality in all sorts of buildings is compromising people’s performance and productivity and, in extreme cases, perhaps undermining the very purpose of the building. And all that we’re doing to create this problem is breathing out.

Outside, where the air is clear, we breathe in carbon dioxide (CO2) at a concentration of around 400ppm (parts per million). That’s not even the way nature intended; until the industrial revolution, CO2 averaged no more than 280ppm.* The air we breathe out carries CO2 at 30,000ppm. Outside, that’s rapidly diluted; indoors in a restricted space, we begin to change the composition of the air and increase the CO2 concentration.
Consider This…
All this exhalation is bad for your health if your indoor air isn’t replenished with fresh air regularly. Here are some symptoms you may well recognise, and the CO2 concentration levels at which they’ll start occurring:

400ppm Typical outdoor air – ideal for clear thinking
600-1,000ppm Starting to notice a little stiffness and even bad smell
1,000ppm+ Drowsiness, feeling tired, yawning – and a drop in decision-making and information-processing performance
2,500ppm Significant drop in decision-making performance
20-30,000ppm Nausea, light-headedness, increased heart rate and breathing
50,000ppm Continuing symptoms, headaches and impaired vision

Indoors, the act of breathing has a cumulative effect on CO2 concentrations, unless that room is ventilated. In a 14m2 office with just one person, CO2 levels can exceed 1,000ppm in 45 minutes. So it makes sense that if you have 20 schoolchildren and a teacher in a classroom for an hour’s lesson, the CO2 levels are going to increase rapidly. The same principle applies to anywhere where people gather indoors: office buildings, hospitals; even your gym. Without good ventilation, CO2 levels will rise throughout the day.

And what’s the real effect of this unnatural air composition? Even with slightly raised CO2 levels children are feeling a little dozy, pay less attention and take in less information. The teacher might be that bit less logical in explaining an important principle. Cumulatively, since that’s the nature of CO2 and we spend up to 90% of our lives indoors and 50% of that time in the workplace or schoolroom, that could mean lower levels of understanding across all subjects and lower levels of attainment.

It’s early yet to tell exactly how we’re affected in the real world, but some studies have revealed results of real concern. A 2015 study in America conducted by a team from Harvard, SUNY Upstate Medical School and Syracuse University involved a controlled office experiment. Manipulating CO2levels from 550ppm to 1,400ppm and having the participants undertake a Strategic Management Simulation test each day at 3pm. At 945ppm, cognitive functions dropped by 15%. At 1,400ppm, the scores plummeted to 50% lower than on the 550ppm days. The results echo a 2012 study (Satish, Fisk et al), which found that at 2,500ppm some performance metrics fell to levels associated with dysfunctional performance.

If learning, teaching and decision-making might be so badly affected by poor air quality, imagine what might happen in a hospital if CO2 levels are unmonitored and uncontrolled.

Creating an internal climate that works

As the damage of climate change becomes clearer, our industry has worked hard to reduce carbon emissions, tighten building envelopes and provide better insulation. The by-product in many buildings has been that CO2 builds up within.

HVAC systems aren’t necessarily helping; in many cases they recirculate a lot of indoor air to manage temperature levels and reduce energy costs. And if we’re largely recirculating CO2-rich air, we’re also not clearing out any pollutants emitted from building materials, furniture and carpets.

The answer lies in real-time CO2 monitoring linked with opening rooflights or rooflights featuring ventilation systems. When concentration reaches a predetermined level, the rooflights are triggered into action, drawing in fresh air and expelling stale, CO2-laden air. It’s even possible to track levels across different parts of a building when the CO2 sensors feed the building management system. That the rooflights also draw in natural light – with all its proven benefits for everything from improved performance to faster post-op recovery rates to reduced absenteeism – should be an? added incentive.

Test the air in your building at 9am and then at several intervals throughout the day. Track the changes in carbon dioxide. Perhaps monitoring this one performance metric could lead to an improvement in all the others.

* Climate Change: What Everyone Needs to Know, Joseph Romm, OUP, 2015



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