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Physical and psychological discomfort in the office environment
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PHYSICAL AND PSYCHOLOGICAL DISCOMFORT
IN THE OFFICE ENVIRONMENT
M.B.C. Aries*, J.A. Veitch, G.R. Newsham
National Research Council Canada, Institute for Research in Construction, Ottawa, K1A 0R6, Canada
* NRC-IRC from 2005-2007; current address for correspondence: Myriam.Aries@tno.nl
ABSTRACT
Office employees spend a lot of time inside buildings, where the physical conditions influence their well-being and indirectly influence their employers’ business performance. With data from a field study conducted in the Netherlands in April-May 2003, we used path analysis to further elucidate the relationship between personal (gender and seasonality of mood shifts), building (view type, view quality, window distance, and social density), and environmental conditions (light quality, and office impression) and physical and psychological discomfort, sleep quality, and hindrance. The results show that window views of nature, and those that are rated as being more attractive, are beneficial to building occupants, reducing discomfort. However, being close to a window and rating the lighting as being of lower quality can result in thermal and glare problems (hindrances). Reduced discomfort at work can improve sleep quality, indicating that physical conditions at work influence home life.
Keywords: discomfort, windows, view, sleep quality
1.0 INTRODUCTION
Office employees spend most of their waking time inside the buildings in which they work, so any problems with the physical environment at work can have substantial influences on them. Inadequate interior conditions can lead to aches and pains such as headaches, eye and nose irritations, or eyestrain e.g., [1-3]. This paper reports an analysis of a field study into the effects of window view and office social density and individual differences on employees’ discomfort at work and sleep quality at home. The analysis used Hedge’s [1] conceptual framework for Sick Building Syndrome (SBS) symptoms, in which individual differences and architectural characteristics together influence perceived or experienced office conditions, which in turn determine SBS symptoms.
The architectural factors studied here were the distance from a window, the view type and view quality, and the social density of the office. Individual factors were gender and mood seasonality. The environmental conditions were perceived conditions: office impressions and lighting quality. The outcome measures were sleep quality, reported physical and psychological discomfort, and problems with hindrances to work.
2 We predicted that window distance would positively affect discomfort, with longer distances to windows resulting in more complaints, because people next to the window should have more control over obstructions like e.g., blinds or plants. Windows provide access to daylight, a view of outdoors, and may provide ventilation (if openable). Preferences for windows are well-established [4-6]. A window view provides information about time and weather and may provide opportunity for ocular relaxation if the view is distant. Natural views, as opposed to built or urban views, tend to improve psychological restoration (e.g., [7-10] and we predicted that urban views would result in more discomfort. However, another way to characterize view is in terms of its aesthetic quality; not all urban views are alike, nor are all natural views equally attractive; we obtained quality ratings of the views, and predicted that higher-quality views would result in fewer discomfort complaints.
According to Duval et al. [11] occupants of socially dense offices — offices in which there are more people — may perceive themselves as having less privacy and less control over the environment because of few behavioural choices and more interference, which in turn leads to environmental dissatisfaction. We predicted that people in offices with fewer occupants would report fewer problems.
2.0 METHODS
This study is a cross-sectional survey of occupants in 10 office buildings in the Netherlands in the springtime (April-May 2003). Ten office buildings, containing private, semi-private, and open-plan office spaces, were visited. Participants completed a questionnaire (43 questions) concerning their experience in the office, with a focus on indoor environment conditions. Physical measurements were taken at a subset of workstations during a site visit. The analyses reported here focus on the survey responses and on the physical conditions that were measured for every workstation; the sampled physical measurements are reported elsewhere [12]. Four physical conditions were available for these analyses: ‘view quality’, ‘view type’, ‘window distance’, and ‘social density’. View type was coded from photographs of the window views from each office. View quality was rated by four independent observers based on photographs of each view, and the average score from the four observers was the value used for each view. Window distance and social density were measured on site.
The employees were told that the intention of the questionnaire was to understand how office users experience present-day office environments and what they think is important. In addition to the usual demographic questions (age, gender, use of corrective lenses), the questions concerned their experiences of the office environment, their propensity for seasonal changes in mood, and the quality of their sleep. Composite variables representing scores on the concepts of interest were created by averaging the related individual item scores. The propensity to experience seasonal mood changes (‘SAD score’) was determined based on whether or not participants self-reported having experienced differences in sleep demands, social activities, mood, weight, and energy level in summer and winter. The total experienced seasonal mood changes in combination with the extent of difficulties they caused
3 formed three categories: none, moderate and large seasonal differences. The ‘light quality’ variable was the total of the survey items: ‘lighting satisfaction in office space’, ‘lighting satisfaction at the desk’, and ‘light quality’, each measured on a 5-point scale (0-4), with higher values indicating better conditions. ‘Office impression’ was the total of eleven survey impression items (e.g., ‘pleasant’, ‘spacious’, ‘quiet’, ‘tidy’, ‘convenient’), each measured on a 5-point scale (0-4), with higher values indicating better conditions.
The ‘discomfort’ variable was the total of ten survey items (e.g., ‘irritability’, ‘headache’, ‘dry throat’, ‘dry eyes’), each measured on a 5-point scale (0-4). Higher values indicate more physical and psychological discomfort. Responses from five of the sleep related items (yes/no scale) were used to assess ‘sleep quality’ resulting in a final scale from 0-5, with higher scores indicating better sleep quality. For the ‘hindrance’ variable, six survey items related to visual and thermal hindrance were used, each measured on a 5-point scale (0-4). Higher values indicate less hindrance. More detailed information is reported elsewhere [13].
3.0 RESULTS
We examined the data for the 10 buildings to determine the degree to which between-building differences might have biased the responses (e.g., systematic differences could have arisen because of the different organizations occupying each building). Based on this analysis, data from one building were excluded. We further examined the data for missing data, univariate and multivariate outliers, and deleted cases if necessary. The final data set contains 211 cases from nine buildings. EQS 6.1 for Windows was used to conduct path analyses [14]. EQS is a structural equations modeling program, which can also be used to perform path analyses. We used commonly-cited criteria to judge the model fit [15;16]. More detailed information is reported elsewhere [13].
The results of the path analysis for the final model are shown in Figure 1. All path coefficients are significant (p=0.05). The final model has a Chi-square of 49.73 on 38 degrees of freedom (p=0.10). The frequency distribution of the standardized residuals revealed that most residuals (86.4%) fell between -0.10 and -0.10, which is desirable. The reliability of the model was tested by means of different fit indices. The minimum discrepancy in our final model is 1.31; a good fit as it is below 3.0. The Root Mean-Square Error of Approximation (RMSEA) of 0.04 indicates a reasonable error of approximation. The model was tested according to other fit indices (see Table 1). As most of the indices show a value over 0.90, we conclude that the suggested model fits the data extremely well.
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Figure 1. Final model relating physical and psychological discomfort to office design parameters Table 1. Goodness of fit for path analysis
N χ² χ²/df GFI AGFI CFI NFI NNFI SRMR RMSEA(90%CI) Optimal value < 3 >.90 >.90 >.90 >.90 >.90 <.10 <.10
Final model 211 49.73 1.31 0.96 0.93 0.96 0.87 0.95 0.06 0.04
NFI =Bentler-Bonnet Normed Fit Index; NNFI= Bentler-Bonnet Non-Normed Fit Index; CFI=Comparative Fit Index; GFI=Joreskog-Sorbom’s GFI Fit Index; AGFI=Joreskog-GFI=Joreskog-Sorbom’s AGFI Fit Index; RMR=Root Mean-Square Residual; SRMR=Standardized RMR; RMSEA = Root Mean-Square Error of Approximation. Optimal values are based on Byrne [15] and Kline [16].
4.0 DISCUSSION
Studying the final model, we see that both the SAD score and discomfort show negative relationships with sleep quality. More discomfort and a higher SAD score result in a reduced sleep quality. The relation between SAD and sleep is not surprising as seasonal sleep difference is an indicator for SAD. Other symptoms of depression such as low mood, loss of interest, difficulties with concentration, loss of energy, and fatigue could simultaneously be reported as physical and psychological discomfort. The SAD score is a strong predictor for physical and psychological discomfort meaning that people with a higher SAD score report more discomfort at work. Sleep has powerful restorative effects on the body and on the ability to perform physical and mental work. However, discomfort can strongly prevent a good night rest, as showed by the negative relationship between the two outcome-variables in our model.
A designer cannot change gender (women report more discomfort than men) and depression sensitivity, but can influence the office environment. The negative relationship between office impression and discomfort in the model shows that the more positive an employee is about his/her office environment, the less physical and psychological discomfort is reported. Not only interior design had influence on discomfort; in our model, three out of four architectural factors have a significant influence on physical and psychological discomfort: ‘view type’, ‘view quality’, and ‘social density’. The more people present in the office room, the more discomfort is reported. A denser population and its activities could
5 make it harder to concentrate, could reduce the air quality, and could mean more effluents. A good view can be associated with fewer self-reported discomfort problems, which is consistent with other studies (e.g., [17]). View quality is a positive predictor for discomfort. Not only the general view quality is important, we also predicted that the type of view plays a role: urban views would result in more discomfort. However, in this study people with a nature view report more discomfort than people with an urban view. This is not consistent with data of e.g. Chang and Cheng [10;18], which indicate that a window with a view of nature has a more positive effect on the human psycho-physiological response than one of an urban scene. This could be an artefact of the particular buildings, locations, and office orientations in the data here. A nature view has a positive influence on the impression of the office environment, and could therefore indirectly contribute to discomfort reduction.
Surprisingly, ‘window distance’ does not seem to have a significant contribution with regard to discomfort. We predicted that window distance would positively affect discomfort, with longer distances to windows resulting in more complaints; but the final model showed no relationship to discomfort, but a negative relationship to hindrance. The lack of relationship to discomfort may arise from the fact that window access is mandatory in the Netherlands, and there were no cubicle partitions. Hindrance on the other hand does have a significant relationship with window distance. As higher values indicate less hindrance, the positive relation means that there is less hindrance with a longer distance to the window, a finding consistent with other literature [19]. Deeper in the room there is less chance for direct sunlight resulting in glare and thermal problems. Hindrance has also a positive link to light quality: people who rated the lighting quality as higher had lower (visual and/or thermal) discomfort, which is consistent with research reported at CIE in July 2007 [20].
These results show that architects, interior designers, and lighting designers all together can contribute to the reduction of the employee’s physical and psychological discomfort, and his/her improvement of sleep quality. The model results show that window views are beneficial to building occupants provided that the potential negative hindrance is avoided, and that reduced discomfort can improve sleep quality.
ACKNOWLEDGEMENTS
This paper is an extended analysis of data collected as part of the first author’s Ph.D. dissertation research at the Technical University of Eindhoven (TU/e), the Netherlands [12]. MBC Aries acknowledges the advice of the promoter Dr. S.H.A. Begemann, the co-promotor Dr. A.D. Tenner, and L. Zonneveldt, M.Sc., and the financial support of Knowledge Center for Building and Systems TNO – TUE (KCBS), during her studies at TU/e. The authors would like to thank all the participants and facility managers in the Dutch buildings visited for their cooperation. They also want to thank Dr. M.R. Atif at NRC Institute for Research in Construction for supporting this extended analysis.
6
REFERENCES
1. Hedge, A., Burge, P.S., Robertson, A.S., Wilson, S., Harris-Bass, J., Work-related illness in offices: A proposed model of the "sick building syndrome", Environment International 15[1-6], 143-158, 1989.
2. Muhic, S., Butala, V., The influence of indoor environment in office buildings on their occupants: expected-unexpected, Building and Environment 39[3], 289-296, 2004/3.
3. Knave, B., Ergonomics and lighting, Applied Ergonomics 15[1], 15-20, 1984/3.
4. Finnegan, M.C., Solomon, L.Z., Work attitudes in windowed vs windowless environments, Journal of Social Psychology 115, 291-292, 1981.
5. Cuttle, C., People and windows in workplaces, Proceedings of the People and Physical Environment Research Conference Wellington, New Zealand, Ministry of Works and Development, 203-212, 1983.
6. Farley, K.M.J., Veitch, J.A., A Room With A View: A Review of The Effects of Windows on work and Well-Being, 2001. 7. Ulrich, R.S., View through a window may influence recovery from surgery, Science 224, 420-421, 1984.
8. Tennessen, C.M., Cimprich, B., Views to nature: Effects on attention, Journal of Environmental Psychology 15[1], 77-85, 1995. 9. Hartig, T., Evans, G.W., Jamner, L.D., Davis, D.S., Garling, T., Tracking restoration in natural and urban field settings:
Restorative Environments, Journal of Environmental Psychology 23[2], 109-123, 2003.
10. Chang, C.-Y, Chen, P.-K., Human Response to Window Views and Indoor Plants in the Workplace, HortScience: HortScience 40[5], 1354-1359, 2005.
11. Duval, C.L., Charles, K.E., Veitch, J.A., Open-Plan Office Density and Environmental Satisfaction, NRC-IRC Research report IRC-RR-150, 2002.
12. Aries, M.B.C., Human Lighting Demands - Healthy Lighting in an Office Environment, Ph.D. thesis, Technische Universiteit Eindhoven, 2005.
13. Aries, M.B.C., Veitch, J.A., Newsham, G.R., Windows, view and office characteristics predict physical and psychological discomfort, in preparation.
14. EQS structural equations program, Bentler, P.M., Wu, E.J., Encino, CA: Multivariate Software, Inc, 2003.
15. Byrne, B.M., Structural equation modeling with EQS and EQS/Windows: Basic concepts, applications, and programming, Sage Publications, Thousand Oaks, CA , 1994.
16. Kline, R.B., Principles and practice of structural equation modeling, Guilford Press, New York, 1997.
17. Heschong, L., Windows and Offices: A Study of Office Worker Performance and the Indoor Environment, Fair Oaks, California, Technical Report Heschong Mahone Group, 2003.
18. Kaplan, R., The role of nature in the context of the workplace, Landscape and urban planning 26, 193-201, 1993.
19. Veitch, J.A., Geerts, J., Charles, K.E., Newsham, G.R., Marquardt, C.J.G., Satisfaction with lighting in open-plan offices: COPE field findings, Proceedings of Lux Europa, 10th European Lighting Conference, pp. 414-417, 2005.
20. Veitch, J.A., Newsham, G.R., Boyce, P.R., Jones, C.C., Office lighting appraisal, performance, and well-being: A linked mechanisms map, Proceedings of the 26th Session of the Commission Internationale de l'Eclairage, Beijing, China, 4-11 July 2007, CIE 178:2007 Vol. 1, D3-61 - D3-64, 2007, Vienna, Austria, CIE.
