Perceived Environmental Qualities and Occupants’ Mental Health, Cognitive Performance, and Satisfaction at Workplaces in China: Survey and Experiment

The World Health Organization (WHO) has reported that over half the world’s population is currently in work, and that 15% of working-age adults live with a mental disorder. Mental disorders and other mental health problems can not only affect a person’s capacity to work productively, but also influence families, colleagues, communities and society at large. The indoor physical environment at a workplace has been recognized as one of the most important factors that can affect mental health and wellbeing. However, evidence clarifying the relationship between the perceived environment of workplaces and occupants’ mental and work performance is limited, especially in Chinese office buildings. This PhD thesis aimed to identify key perceived environmental characteristics in Chinese offices and explore their effects on office workers’ mental wellbeing, cognition, mood, affective response and satisfaction. This PhD project adopted a systematic literature review, a cross-sectional survey, and psychological experiments as its main methods. First, the systematic review applied the PRISMA method and retrieved 55 key studies from 14173 articles that were identified using six frequently accessed databases. The main research hypotheses were thus developed. Second, a cross-sectional survey was implemented in 108 office buildings in China’s four main urban agglomerations. The physical environments of these offices were assessed by trained surveyors, and subjective feedback on perceived environmental qualities, mental well-being and satisfaction was collected from 1131 occupants. Third, psychological experiments were conducted in two offices (private and open-plan), testing the effects of several critical environmental interventions (indoor plants, wall posters, window view and window proximity) on participants’ physiological and cognitive performance, mood, affective response and satisfaction. A total of 636 participants (female: 52.5%) and 488 participants (female: 54.5%) were recruited for the private and open-plan office experiments, respectively. The apparatus and instruments used were bio-monitoring sensors for physiological indices (heart rate variability and electrodermal activity), psychomotor vigilance tasks and Stroop tests for cognitive performance, Positive and Negative Affect Schedule for mood, and a self-developed questionnaire for affective response and satisfaction. Key findings: 1) Cross-sectional survey: Occupants’ mental wellbeing was significantly affected by four physical factors (naturalness of interior finish material, finish colour, workstation area, HVAC system) and three perceived factors (privacy, indoor climate, cleanliness and maintenance), while clear effects on satisfaction were found for nine physical factors (number of business events centre, number of amenity space, naturalness of interior finish material, finish colour, naturalness of finish pattern, window to wall ratio, workstation area, number of equipment and supplies, HVAC system) and four perceived factors (decoration, privacy, indoor climate, cleanliness and maintenance). However, the effects of these environmental factors could be fully or partially mediated by the psychosocial factor. 2) Psychological experiment 1 (private office): The presence of indoor plants significantly affected mood, affective response and satisfaction, while small and medium amounts of plants clearly influenced physiological performance. Nature content posters significantly impacted physiological performance, affective response and satisfaction; only affective response was significantly affected by urban content posters. Both natural and urban window views significantly affected physiological performance, mood, affective response and satisfaction. However, the four environmental interventions did not significantly impact cognitive performance. 3) Psychological experiment 2 (open-plan office): The presence of indoor plants significantly affected only physiological performance and affective response. Clear effects of natural (but not of urban) window views were found on physiological performance, and mood, while both natural and urban window views can affect affective response and satisfaction. Proximity to a natural window view could significantly influence physiological and cognitive performance, affective quality and satisfaction, while no significant impact on the three outcomes was found for proximity to an urban window view. As in the private office, no clear relationship was found between these environmental interventions (except for window proximity) and cognition in the open-plan office.