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Procedia Engineering 165 ( 2016 ) 242 – 250

15th International scientific conference “Underground Urbanisation as a Prerequisite for Sustainable Development” Human-centered development of underground work spaces

a, a a a Chee-Kiong Soh *, George Christopoulos , Adam Roberts , Eun-Hee Lee

aSchool of Civil and Environmental Engineering, Nanyang Technological University, Singapore bNanyang Business School, Nanyang Technological University, Singapore

Abstract

Underground space is being diversified for more and more functions, including industrial, commercial, transport, educational, and recreational uses. Mixed-use complexes and multi-functional hubs are also being developed underground. As more uses are found for underground space, we should ensure that underground working does not affect human psychology and health. Previous research has examined psychological, health and social aspects associated with underground spaces but mainly employing relatively mono-disciplinary approaches and methodologies, many times in a non-systematic way. Additionally, research up to now has not employed the modern research tools that cognitive neuroscience, experimental social psychology and epidemiology offer. Our research project examines human health, behavior and attitude aspects related to the underground working environment in a multi-disciplinary and holistic way. The overall aim is to examine and address possible psychological and health-related impacts and to enhance social acceptance of underground workspaces. This project begins a unified, systematic and holistic examination of the interaction of human psychology and health with underground spaces to improve public acceptance of underground work. In this study, we present the key elements of a systematic research program examining the relationship between environmental and architectural characteristics of underground spaces with human behavior, cognition and -being. Initial findings of the research plan show a multi-faceted set of aspects that can affect underground work, from psychological effects on work performance and creativity, social effects on cooperative and risk taking behaviors, health effects, and engineering parameters such as the aesthetic appearance of the space.Problems can arise from the design of underground workspaces, such as disruption from regular exposure to the outdoor environment. Social beliefs, attitudes and cultural meanings can affect the willingness to work underground. The confined environment that is created can amplify issues that are common to all workplaces, including environmental, emotional and motivational factors. ©© 2016 2016 The The Authors. Authors. Published Published by Elsevier by Elsevier Ltd. This Ltd .is an open access article under the CC BY-NC-ND license (Peerhttp://creativecommons.org/licenses/by-nc-nd/4.0/-review under responsibility of the scientific). committee of the 15th International scientific conference “Underground Peer-reviewUrbanisation under as aresponsibility Prerequisite of for the Sustainable scientific committee Development of the .15th International scientific conference “Underground Urbanisation as a Prerequisite for Sustainable Development

* Corresponding author. Tel.: ++65-94880132. E-mail address: [email protected]

1877-7058 © 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the scientific committee of the 15th International scientific conference “Underground Urbanisation as a Prerequisite for Sustainable Development doi: 10.1016/j.proeng.2016.11.796 Chee-Kiong Soh et al. / Procedia Engineering 165 ( 2016 ) 242 – 250 243

Keywords: urban underground space, psychology, health, attitudes.

1. Introduction

Underground space use is steadily increasing. Factors contributing to this are the advancement of excavation technology and the increase in land prices associated with land scarcity. It is projected that 66% of the world’s population will be living in urban areas by 2050 (UN-DESA, 2014) , increasing urban density and in turn increasing underground space use. There are many possible traditional aboveground activities that could be moved underground, including office and retail work. However, it is important to ensure that any activities and workers that are moved underground are not negatively affected. In recent years, underground space planning has started to become more human-centered, emphasizing user satisfaction and attractiveness alongside function. This is important, as architectural features have been shown to affect job performance and satisfaction (Sundstrom et al., 1980). Much of the research on underground work that is cited when considering human-centred design is more than thirty years old. Therefore we must consider this research in the context of modern advancements in research methods and scientific theories.

2. Key factors

Previous research (see Roberts, Christopoulos, Car, Soh, & Lu, 2016; Lee, Christopoulos, Lu, Quan, & Soh, 2016 for more detailed accounts) has identified various possible issues with underground spaces that require examination. In the following sections, we will look at key research areas relating to underground space: (1) Architecture & Environment, (2) Social attitudes, (3) Cognition, and (4) Health. Figure 1 illustrates the interrelationship between these areas, where multiple areas can be concerned with the same common factors.

Fig. 1. Key factors and research areas associated with underground workspaces. 244 Chee-Kiong Soh et al. / Procedia Engineering 165 ( 2016 ) 242 – 250

2.1. Architecture & Environment

Many environmental factors traditionally associated with underground work, such as air quality, noise, dim lighting, and thermal comfort can now be solved by modern engineering solutions. This allows underground environments to maintain their environmental parameters to the same level as any aboveground office environment (see Roberts et al., 2016 for a discussion). However, there are some aspects of underground spaces that cannot be made to equal their aboveground counterparts. Zhao & Künzli (2016) detail four important aspects of space that are reduced in underground spaces. These are: (1) Visibility of aboveground, (2) Accessibility of aboveground, (3) Visual contact with nature, and (4) Interconnection of spaces. Visual and physical connectivity are very important aspects of space, as they can reduce feelings of isolation and claustrophobia. As Labbé (2016) points out, aboveground space between buildings is automatically open and public. This contrasts with the space between underground structures which is inaccessible, filled with rock and soil. Therefore consideration should be paid towards creating large communal hubs within underground spaces that can act as connections between workspaces. The lack of aboveground view from underground spaces (i.e. lack of windows) may affect long-term workers in underground spaces. Health studies have shown that having access to a natural scene, such as through a window, has been shown to improve recovery time of surgical patients (Ulrich, 1984). In a workplace context, windows enhance work and wellbeing ratings in questionnaires, but may not affect actual work productivity (Farley and Veitch, 2001). While this points to windows not being necessary from a strict work efficiency point of view, it is important to note that a lack of windows increases turnover intention (Finnegan and Solomon, 1981) and may have an effect on mental resources affecting decision making (Kaplan and Berman, 2010).

2.2. Social Attitudes

People commonly make snap judgements (immediate value decisions) when evaluating aesthetic appearances of environments, faces and products. These snap judgements are often based on cognitive biases and are limited by the availability of cognitive resources (Christopoulos et al., 2011). This means that people that are tired, under stress, or otherwise mentally taxed may be more likely to make negative judgements about underground spaces. Carmody (1992) found that underground space is associated with negative attitudes and imagery. Some of the negative imagery can be related to deep-rooted cultural sources, such as religion. For example, many western and eastern religions have a concept of an "underworld" which associates underground space with punishment for worldly sins. Underground spaces can activate the concept of burial, creating feelings of isolation and entrapment (Hane et al., 1991; Hollon et al., 1980). Negative attitudes about underground spaces, such as fear and uneasiness (Ringstad, 1994) may be symptoms of specific characteristics of underground space that people will instinctively avoid. Moreover, there is a tendency to associate underground spaces with underprivilege, where lower class people are more likely to live lower down, and a recent trend of migrant workers living in underground shelters in Beijing has led to them being named the "mouse tribe" (Huang and Yi, 2015). Positive images associated with underground spaces tend to be related to security and safety (Mohirta, 2012), as underground spaces may provide shelter from possible environmental disasters (e.g. tornadoes, earthquakes) aboveground. However, this appears to be influenced by culture, as Hane et al. (1991) found that Americans were more likely than Japanese to use the word "comfort" when describing underground spaces. In weighing the utility of public attitudes when considering the construction of underground spaces, it is important to note that frequent exposure to underground environments can affect these attitudes. There is a "double divide" between aboveground and underground space (Labbé, 2016), causing a spatial segregation in the mind of the public. Underground built space is seen as private and for technical use, whereas aboveground built spaces are seen as public and for urban use. People who commonly work in underground spaces are more willing to move to another underground workplace than those who have never worked underground (Carmody and Sterling, 1990). These underground workers were more likely to accept improvements to their current underground workspace than an offer to move to an aboveground workspace. People who have never worked underground assume that underground workplaces would have problems with dim lighting, but underground workers are generally satisfied with their level of lighting (Hane et al., 1991). It seems, therefore, that underground workspaces suffer primarily Chee-Kiong Soh et al. / Procedia Engineering 165 ( 2016 ) 242 – 250 245 from an unfairly poor image. In many cases, the general public will resist major innovations (Rogers, 2010) and will take time to accept these innovations into their daily lives. However, the public crowd-funded Lowline project in New York (Admiraal and Cornaro, 2016) shows that people can be enthusiastic about underground space when it is clearly innovative and inclusive.

2.3. Cognition

While negative attitudes to underground spaces may be resolved by greater education or exposure, these negative attitudes should not be ignored. Anxiety relating to underground spaces can come from worry about being isolated or trapped (Carmody and Sterling, 1993; Wada and Sakugawa, 1990). Up to seven per cent of the world suffer from claustrophobia (Rachman and Taylor, 1993). Claustrophobia and other anxiety disorders have been shown to affect work performance, reducing productivity and concentration, and increasing mistakes (Wald, 2011). Similarly, Paul (2009) showed that a combination of job dissatisfaction and negative attitudes about an underground workspace can be a predictor of workplace injury in . Paul found a higher than double incidence of injury in workers that were highly negatively affected by their work. Another possible cause of negative attitudes to underground spaces is lack of perceived control over the environment (Ringstad, 1994). Lack of direct access to outdoors and expected difficulty in wayfinding can cause a lack of confidence, resulting in reduced perceived control, in turn resulting in an impression that the underground environment is dangerous and unsafe (Carmody, 1993; Ringstad, 1994). Reduced perceived control has been shown to cause disengagement from work and a lack of attention (Pekrun et al., 2010). This also interacts with anxiety, where the degree to which a stimulus or environment increases anxiety depends on the level of perceived control (Beck et al., 1985). It has been shown that increasing environmental control over a worker's physical environment can improve performance and wellbeing (Becker, 1985; Langer and Rodin, 1976), suggesting that simple interventions, such as user-controllable lighting or air conditioning, may increase worker comfort and acceptance of an underground workplace. In a preliminary study by Lee, Christopoulos, Liew, & Roberts (2016), negative attitudes to work environments were seen to be greatly affected by the level of perceived control of a worker. Here, a higher level of perceived control mediated the effect of claustrophobia on a person's willingness to work.

2.4. Health

An examination of underground workers by Wada & Sakugawa (1990) showed that subjective reports of the workplace focused on perceived impacts on health. However, studies of actual health outcomes from underground working tend to identify other factors as probable causes, such as inadequate lighting and ventilation (Holister, 1968). For example, high levels of carbon monoxide in the breath of underground workers (Wallace, 1983), were traced to the neighboring parking garage and resolved by simple mechanical interventions. Holister (1968) describes initially worrying negative health effects when underground factories were first opened in Sweden, including complaints of headaches, fatigue and insomnia. However, blood tests showed no differences from an aboveground workplace. When these tests were repeated eight years later, these negative complaints had practically disappeared. No changes were seen in the blood tests of those who had been working underground all that time. Studies that compared pupils in an underground school to those aboveground showed no evidence of physical or mental health problems (Cooper & Ivey, 1964; Lutz & Lutz, 1964; Lutz, Lynch & Lutz, 1972). And while Wada & Sakugawa (1990) showed increases in self-reported fatigue in underground workers, these increases were not seen in any physiological measures of fatigue. One possible aspect of underground work that may affect health is lack of exposure to natural sunlight. Sunlight is vital in the synthesis of vitamin D, required for prevention of rickets, diabetes, and other medical conditions (Björn, 2008). However, synthesis of vitamin D requires exposure to UV-B radiation (Glerup et al., 2000), which is blocked by normal window glass. As many people spend the vast majority of their time indoors (for example, Dirani et al., 2009 found that Singaporean children spent more than 85% of any 24 hour period indoors), it is unclear whether this would be a significant factor for underground workers, who would only be underground during working hours. Compare this to submarine workers, who spend prolonged periods in dim artificial lighting and have shown deficits in vitamin D production (Baker et al., 2014). 246 Chee-Kiong Soh et al. / Procedia Engineering 165 ( 2016 ) 242 – 250

An alternative issue with a lack of exposure to natural sunlight is the possible effect on the circadian rhythm. The circadian rhythm is a daily cycle, controlling hormonal and neurochemical releases and sleep-wake patterns (see Figure 2). The circadian rhythm is controlled by the cycle of light and dark in a worker's environment ( et al., 2003). Two major hormones that are regulated by the circadian rhythm are melatonin and cortisol. Melatonin controls the sleep response (Arendt, 1995), being low during the day, increasing in the evening, and peaking at night. Melatonin not only affects sleep, but plays a role in enzyme regulation, retinal physiology, immune modulation and blood pressure modulation (Reiter et al., 2014). Therefore any changes in melatonin release related to underground work would need to be carefully studied. Underground workers have shown higher diurnal melatonin variation than aboveground workers, causing them to sleep longer and fall asleep more easily (Küller and Wetterberg, 1996). However, this may have been caused by generally dimmer artificial lighting in the underground environment than the aboveground environment, and brighter artificial lighting may counter this effect. Kuller & Wetterberg also showed an effect of underground work on cortisol levels, where they were more stable over the year than for aboveground workers. Cortisol levels vary both with the circadian rhythm and with work demands and stress. Cortisol levels are highest in the morning, reducing over the course of the day. Changes in work demands can momentarily increase the level of cortisol. In Kuller & Wetterberg's study, underground workers showed lower cortisol levels in the afternoon than aboveground workers, but it is not clear if this was caused by lighting, a more stable working environment, or reduced environmental stimulation. There is much agreement on the effect of bright light on health. Walch et al. (2005) found that patients in rooms lit by bright natural light required less analgesic medication and had greater decreases in stress compared to patients in dim rooms. Beauchemin & Hays (1998) found that bright natural light reduces recovery time for clinical depression. A review of the recent literature by (Boubekri et al., 2014), shows that both natural and artificial bright light in the morning improve circadian rhythms and reduce incidences of depression. Therefore any underground workplace must consider carefully the type of lighting installed.

Fig. 2. Circadian variation of melatonin and cortisol. From Roberts et al. (2016).

3. Looking to the future

As future underground spaces are being planned and built, human centric research should be considered and incorporated. Already we can start to see possible suggestions based on previous research in psychology and health, although considering the age of some of the studies, these areas should be reexamined more closely. Previous interventions to improve worker comfort in underground spaces have already been attempted, with varying degrees of success (c.f. Carmody & Sterling, 1987; Fuhlrott, 1986; Scuri & Skene, 1990) and while certain aspects have been successful, there have been few follow ups to determine the efficacy of these interventions. A comprehensive analysis of possible interventions is required to determine what aspects are effective. One possible method of study is virtual reality, which allows for rapid prototyping and simulation of different environments (Flø and Jenssen, 2007). This allows a much more controlled environment than the real world, but with greater ecological validity Chee-Kiong Soh et al. / Procedia Engineering 165 ( 2016 ) 242 – 250 247 than laboratory tasks. Virtual reality environments have been used to replicate both underground and aboveground spaces with similar psychological effects as real environments (e.g. Knez & Niedenthal, 2008; Mühlberger, Herrmann, Wiedemann, Ellgring, & Pauli, 2001). This can be used in association with modern cognitive neuroscience techniques, such as fMRI, EEG and eye tracking to identify the exact mechanisms underlying effects seen in underground work (Roberts et al., 2016). In situations where chronic exposure to underground work is investigated, wearable technology can be used to monitor activity and physiology over the course of several weeks. Lee et al. (2016) outlines a conceptual framework for studying the impact of underground workplaces on social factors. This framework makes predictions on behavior of occupants of underground spaces, both good and bad (see Figure 3). We intend to test specific aspects of this framework to identify future interventions that could be employed to improve the design of underground spaces.

Fig. 3. A conceptual framework of the social impact of underground work. Adapted from Lee, et al. (2016).

As underground workspaces lack connection to the outside world, future designs should attempt to mitigate this. One method suggested by Carmody & Sterling (1987) is to use elevators from ground level to enter the underground space. In this way, the entry is seen as similar to entry to a high-rise building. We would suggest that increasing the number of elevators beyond that normally used in aboveground buildings could reduce the perceived effort workers would feel in relation to leaving the space. In addition, light and skylights could be used to increase feelings of connection to the outdoors as well as allowing natural light inside (Figure 4). Another way of increasing feelings of connection to the outdoors would be to place plants in the workplace. It has already been shown that workers in underground and windowless spaces tend to decorate their workplace with plants and pictures of natural scenes (Bringslimark et al., 2011), and Sato & Inui (1994) demonstrated that introducing plants to a windowless room improved task performance more than other decorations. In deeper underground structures, natural light can be brought inside using light pipes (Gil-Martín et al., 2014). If this is not possible, workers should be encouraged to venture aboveground to expose them to sufficient natural sunlight during the day. This could be done through modification of shift patterns or through setting rest areas and canteens aboveground.

248 Chee-Kiong Soh et al. / Procedia Engineering 165 ( 2016 ) 242 – 250

Fig. 4. Example light well (“sun valley”) in the Expo Axis, Shanghai, China.

4. General conclusions

Previous studies of underground workspaces have not given enough evidence to make conclusions about the impact on worker health, productivity or long term wellbeing. While subjective reports and questionnaires indicate negative attitudes to underground work, it is unclear whether these are caused by something intrinsic to underground work, or rather pre-existing cultural and societal norms. We propose that there is a need for a deeper understanding of the mechanisms relating to human health and wellbeing in underground spaces, and this can only come about through the combined efforts of researchers spanning multiple disciplines.

Acknowledgments

This material is based on research/work supported by the Land and Liveability National Innovation Challenge (L2 NIC) Award No. L2NICCFP1-2013-2 (PI: Chee-Kiong Soh).

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