Indoor air quality investigation before and after relocation to WELL-certified office buildings

Air pollutant exposure in workplace environments has been associated with health and cognitive outcomes of workers. While green building certification programs have been instrumental in promoting indoor air quality (IAQ), the present literature indicates inconsistent evidence. Recent emergence and proliferation of WELL certification program that prioritizes human health has evoked new questions about its effectiveness in relation to IAQ. To investigate the effectiveness of the WELL certification, we have quantitatively compared IAQ results before and after relocation to two WELL-certified office buildings using the same cohort of occupants. Physical measures included integrated samples of TVOC, individual VOC, formaldehyde and acetaldehyde, NO2, SO2, O3 and longitudinal records of CO2 and size-resolved particles. Complementary survey responses about satisfaction with IAQ and thermal comfort were collected from ~250 employees. For the majority of air pollutants, there was no significant concentration difference between non-WELL and WELL buildings, but not always. The WELL-certified buildings had substantially higher levels of TVOC and individual VOC associated with paints, especially shortly after the relocation. However, there was statistically significant improvement in IAQ satisfaction after relocation into WELL buildings regardless of the air pollution levels, possibly confounded by thermal environment, awareness of the WELL certification or other non-measurable factors.

Daylight and temperature in buildings: interaction effects on human responses

Giorgia Chinazzo

Over the past years, increasing efforts have been devoted to understand how people perceive the indoor environment with the goal to improve building design and operation. Studies have separately addressed the effects of the four main aspects that influence the perception of the indoor environment, i.e., visual appearance, thermal condition, acoustic ambiance, and air quality. However, building occupants are simultaneously exposed to multiple indoor stimuli and their perception of the indoor environment depends on the mutual combination and interaction of such stimuli. Despite the increasing interest in the topic, few studies on the interactions between indoor factors are available. Most of them have focused on interactions between thermal and visual factors due to their large implications for energy consumption and building design. In this context, electric lighting has been primarily used as visual stimulus, leaving a knowledge gap on interaction effects in daylit environments. To address this challenge, this doctoral thesis focuses on the effects of visual and thermal interactions on human responses, with the use of daylight as the sole source of light. Two types of visual-thermal combinations are investigated: temperature and "daylight color" (i.e., daylight transmitted through colored glazing) and temperature and daylight quantity (i.e., illuminance levels). The aim of this work is threefold: (i) understand the effect of daylight color and quantity on thermal perceptual and physiological responses; (ii) investigate the influence of indoor temperature on visual perception of daylight; and (iii) explore the effect of daylight and temperature combination on the overall comfort perception. To address the previous aspects, four experiments were conducted. Two of them were carried out in an office-like test room to investigate both visual-thermal combinations. One field study was performed to further explore temperature and daylight quantity interactions. One experiment was conducted in a test room with the use of virtual reality to further investigate temperature and "daylight color" interactions. The results of this thesis show that daylight and temperature do interact, influencing human responses in a perceptual rather than in a physiological way. The interaction effects are bi-directional, as temperature influences visual perception, and daylight color and quantity affects thermal perception. Daylight conditions and indoor temperatures simultaneously and equally contribute to the overall comfort perception, but only after a relatively long exposure to the visual stimulus. The findings of this research suggest that indoor factors should not be considered separately but in combination. The integration in both research and practice of interaction effects between indoor factors will ultimately contribute to the improvement of comfort conditions inside buildings. Potentially, this integration will also allow to reduce the energy consumed in buildings to guarantee occupants' comfort due to the extension of the comfort ranges that currently neglect interaction effects between indoor environmental factors. Disentangling for the first time the complex relationship between daylight and indoor temperature, this research constitutes an additional step towards understanding interactions of indoor factors and contributes to the establishment of a comfortable and energy-efficient built environment.

EPFL2019

Occupant satisfaction with indoor environmental quality, sick building syndrome (SBS) symptoms and self-reported productivity before and after relocation into WELL-certified office buildings

Dusan Licina, Serra Yildirim

Recent green building certification programs have put a strong emphasis on occupant health and well-being. For recently emerged WELL certification, we lack evidence about its effectiveness in relation to occupant satisfaction, productivity and health. Here, we compared the results of occupant satisfaction with the indoor environmental quality (IEQ) obtained from the same cohort of employees who transitioned from three non-WELL (two BREEAM and one conventional) to three WELL-certified office buildings. For two out of three building pairs, we found a statistically significant increase in building and workspace satisfaction after relocation to WELL buildings. However, for 55 % of compared cases, there was insignificant difference as the result of relocation. The positive effect of WELL certification was evident for parameters such as building cleanliness and furniture, but there was no difference in satisfaction with noise and visual comfort. Relocation from BREEAM to WELL buildings had insignificant effect on satisfaction with IEQ, except for air quality in one case. Regardless of the certification label, buildings usually did not attain the 80 % standard satisfaction threshold. The satisfaction scores did not alter during the first year of working in WELL buildings. We also observed that the level of certification did not scale with the overall building satisfaction scores. Comparisons between the occurrence of Sick Building Syndrome (SBS) symptoms and self-reported productivity scores revealed insignificant differences between WELL and non-WELL buildings, except for symptom of tiredness that was lower in WELL buildings. The effect of Covid-19 measures interfered with the self-reported work abilities of 78 % of occupants.

2021

Daylight and temperature in buildings: interaction effects on human responses

Giorgia Chinazzo

EPFL2019