Having Trouble Breathing
Your perception of your office’s air may be more accurate then you imagine, writes Dr L.T. Wong.
Ever get the feeling that the air in your office is a little stale? A recent study by The Hong Kong Polytechnic University revealed that 39 percent of Hong Kong offices have poor Indoor Air Quality (IAQ). The key to identifying underperforming workplaces may lie in the occupants perception of carbon dioxide levels.
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Over the past decade there has been growing concern over complaints by corporate occupiers regarding the implications of IAQ on the health and productivity of their workers. But while the government’s response, the HKEPD Scheme, quantifies and regulates the quality and testing of indoor air, many questions have been raised about the costs and feasibility from a landlord and occupier perspective. Establishing an effective screening process for the IAQ is crucial for ameliorating workplace conditions. But not only are the current sampling protocols costly and complicated, many may even cause misleading results. At The Hong Kong Polytechnic University, we embarked upon a study to identify a more practical and rational approach to testing the air that we breathe in our offices.
Studying air
To establish the best procedure, we assessed a random sample of 422 workplaces in Hong Kong. We monitored the 12 common indoor parameters specified by the HKEPD Scheme, while at the same time asking the occupants if they found the levels of carbon dioxide acceptable within their office. The first, and most alarming, finding was that 39 percent of offices tested had an unsatisfactory performance. This was caused by was levels of total volatile organic compounds, airborne bacteria, formaldehyde and ozone that exceed the criterion for ‘good’ IAQ.
Our second finding points the way towards a simple and efficient screening tool. We examined the correlation between occupier acceptance of carbon dioxide levels and actual concentrations, and found that there was a reasonable agreement between their predictions (low acceptance meant high levels). Furthermore, we found that this could also be used as an indicator of general IAQ for the purposes of initial screenings. In fact, our study showed that decreased occupant acceptance can indicate that a workplace is 50 to 600 percent more likely to have unsatisfactory IAQ.
If we are to face up to the problems of poor IAQ, the first step is establishing the scale of the task. Occupant acceptance is a useful screening parameter, and one that enhances the feasibility of more in-depth testing being carried out. With a high number of offices in Hong Kong showing unsatisfactory performance, IAQ is becoming a serious occupational health and safety issue. The time to act is now.
Dr L.T. Wong is an Associate Professor at The Department of Building Engineering, The Hong Kong Polytechnic University.
