The effects of poor air quality on indoor environments

Imagine that you have found your new office space. Before moving in, you apply new paint, do some remodeling, decorate and furnish the place ─ but is that all? Try to recall why you selected this building; you probably looked for a place that would be restorative and conducive to efficiency. If so, does your checklist include actions to ensure that the indoor environmental quality indicators are at adequate levels? Indoor environmental quality is less noticeable than the tangible items you checked off your list, and therefore may be overlooked or treated with less care than something like modern ergonomic furniture. It is, however, as important ─ if not more so ─ as the other features of your new office.

The dilemma described above ─ regarding efficiently financing an indoor space that is welcoming and comfortable, yet also facilitates productivity ─ is common. This brief article outlines a few tips on this matter. It provides a concise summary of the laboratory and field studies quantifying the effects of indoor environmental quality (particularly the thermal environment and indoor air quality) on work performance, as well as their economic implications. The article finishes with some short- and long-term goals and challenges for research on indoor environmental quality and its impact on office workers’ performance.

Indoor environmental quality and productive work

People who do not feel well will not work well ─ investigations in office buildings show that office workers who report any acute health symptoms perform significantly worse compared to workers with no acute health symptoms.¹ Much attention has been given recently to research that has shown that indoor environmental conditions can, in fact, also impact office workers’ health and performance. Studies performed to date are consistent, showing that thermal discomfort and poor indoor air quality have considerable consequences for work performance.² They also show that similar or even larger impacts are observed for schoolwork and learning,³ though they are not described in the present article.

Thermal environment and work performance

Studies have linked thermal comfort and work performance. For example, work performance has been estimated to decrease by roughly 1 percent for every 1^oC deviation from the optimal temperature.⁴ The optimal temperature corresponds to conditions that produce thermal sensation slightly below neutral and not, as it would be expected, thermal neutrality.⁵ Avoiding thermal discomfort is therefore essential for optimal work performance and reducing the risk of various health symptoms.⁶

Indoor air quality and work performance

There has been a lot of research that has tried to estimate the impact of indoor air quality on work performance. For example, lowering the percentage of building occupants dissatisfied with indoor air quality by 10 percent has been predicted to increase work performance by roughly 1 percent;⁴ doubling the outdoor air supply rate by increasing ventilation has been estimated to increase office work by about 1.5 percent.⁴ It is of note that ventilation is used here as a marker of indoor air quality. Further, poor air quality not only has an effect on work performance ─ doubling the outdoor air supply rate in offices has also been estimated to reduce the prevalence of sick-leave by roughly 10 percent.⁴ Adequate ventilation and the avoidance of pollution sources that diminish indoor air quality are therefore essential for optimal work performance and good health.⁷

It is not only the workplace that impacts performance: Indoor environmental quality in bedrooms influences next-day work performance

Sleep is essential for health and next-day performance; a consistent lack of sleep may be linked to diseases like dementia, diabetes and cancer.⁸ Studies show that bedroom temperatures are often too high, and air quality is often poor due to inadequate ventilation.^9,10 These conditions were shown by multiple studies to reduce sleep quality and next-day performance.^11,12,13

Economic consequences of reduced work performance

Just a few percentage points decrease in work performance has substantial economic implications because the cost of the workforce is up to 100 times higher than the cost of a building’s construction and operation.¹⁴ Economic calculations show that a 10 percent increase in work performance can offset the full cost of installation and operation of a building that is needed to produce this increase.¹⁵ Accounting for the increase in work performance with economic calculations results in payback times for investments in indoor environmental quality that are generally less than two years, and often even shorter.^16,17

A need for a metric of work performance

Research has shown consistently and beyond doubt that good indoor environmental quality can improve work performance. But the effects on performance are measured mainly using objective methods such as cognitive tests typically employed in neuroscience and psychology, and selected tasks simulating office work; only in very few cases was the actual work output used as a metric of performance. Furthermore, in general, the effects of single variables are examined. The challenge now is to understand how the magnitude of these observed effects aligns with performance in real office settings with varying types of work, as well as how the effects of different parameters defining indoor environmental quality combine and interact. The latter will represent the actual exposures in the workplace. To meet the former, it is important to develop methods to measure work performance in practice. These methods would include the comparison of results across different building populations and the alignment of work outputs with health outcomes and sick-leave measures. As no such standard performance method or metric exists at the moment, it has become popular to ask building occupants to rate how well they work; however, no study has yet shown that these ratings align with objectively measured work performance.²

Future outlook

The list of future research topics on work performance is long,¹⁸ and groups such as the Survey Working Group at IWBI^TM are engaged in addressing some of these gaps. It seems clear, however, that solid next steps are: developing performance metrics in real-world settings; studying the combined effects of the thermal environment and indoor air quality on office work; and using performance metrics as one of the design parameters of future office buildings. Although more research is needed, the simple takeaway is that neglecting the importance of indoor air quality and thermal conditions for work performance can be very costly.

---

1. Nunes, F., Menzies, R., Tamblyn, R.M., et al. (1993) “The effect of varying level of outdoor air supply on neurobehavioural performance function during a study of sick building syndrome (SBS),” Proc. Indoor Air '93, Vol. 1, 53-58.

2. Wargocki, P., & Wyon, D. P. (2017). Ten questions concerning thermal and indoor air quality effects on the performance of office work and schoolwork. Building and Environment, 112, 359-366.

3. Wargocki, P., & Wyon, D. P. (2013). Providing better thermal and air quality conditions in school classrooms would be cost-effective. Building and Environment, 59, 581-589.

4. Seppänen, O. A., & Fisk, W. (2006). Some quantitative relations between indoor environmental quality and work performance or health. HVAC&R Research, 12(4), 957-973.

5. Lan, L., Wargocki, P., and Lian, Z. (2011). Quantitative measurement of productivity loss due to thermal discomfort. Energy and Buildings, 435, pp.1057-1062.

6. Fang, L., Wyon, D. P., Clausen, G., & Fanger, P. O. (2004). Impact of indoor air temperature and humidity in an office on perceived air quality, SBS symptoms, and performance. Indoor air, 14, 74-81.

7. Carrer, P., Wargocki, P., Fanetti, A., Bischof, W., Fernandes, E., Hartmann, T., Kephalopoulos, S., Palkonen, S., and Seppänen, O. (2015). What does the scientific literature tell us about the ventilation–health relationship in public and residential buildings? Building and Environment, 94, pp.273-286.

8. Walker, M (2017) Sleep the good sleep. New Scientist, 14 October, 30-33.

9. Bekö, G, Lund, T, Nors, F, Toftum, J and Clausen, G (2010). Ventilation rates in the bedrooms of 500 Danish children. Building and Environment, 45(10), 2289-2295.

10. Sekhar, SC, and Goh, SE (2011). Thermal comfort and IAQ characteristics of naturally/mechanically ventilated and air-conditioned bedrooms in a hot and humid climate. Building and Environment, 46(10), 1905-1916.

11. Lan, L., & Lian, Z. (2016). Ten questions concerning thermal environment and sleep quality. Building and Environment, 99, 252-259.

12. Strøm-Tejsen, P., Zukowska, D., Wargocki, P., and Wyon, D. (2016). The effects of bedroom air quality on sleep and next‐day performance. Indoor Air, 26, pp.679-686. (DOI: 10.1111/ina.12254).

13. Wargocki, P., Lan, L., Lian, Z., & Wyon, D. P. (2018). Thermal environment, IAQ, and sleep. ASHRAE Journal, 60(4), 60-63.

14. Woods J E, and Jamerson W E. 1989. Cost avoidance and productivity in owning and operating buildings. Occupational Medicine. Vol. 4, pp 753-770.

15. Wargocki, P., & Seppänen, O. (2006). REHVA Guide Book no. 6, Indoor Climate and Productivity in Offices, How to integrate productivity in life cycle cost analysis of building services. REHVA, The Federation of European Heating, Ventilation, and Air Conditioning Associations.

16. Dorgan C B, Dorgan C E, Kanarek M S, and Willman A J. 1998. Health and productivity benefits of improved indoor air quality. ASHRAE Transactions. Vol. 104(1A), pp 658-666.

17. Wargocki, P., & Djukanovic, R. (2005). Simulations of the Potential Revenue from Investment in Improved Indoor Air Quality in an Office Building. ASHRAE transactions, 111(2).

18. Clements-Croome, D. (Ed.). (2017). Creating the productive workplace. 3rd Edition. Taylor & Francis.