An effective alerting strategy to facilitate occupants' perception of indoor air quality: By alarming concentration of indoor air pollution.

Previous studies have proven that it is hard for occupants to perceive concentration of indoor air pollution (IAP) and resulting indoor air quality (IAQ) on their own. Therefore, a method is needed to encourage them to turn their attention to actual IAP, in this context, alerting is thus suggested. However, previous studies pose limitations in that they failed to analyze the effects of alerting concentration of IAP on occupants' IAQ perception. To fill the research gap, this study sought to explore a proper strategy to help occupants have a clearer perception of IAQ. A one-month observational experiment was conducted on nine subjects under three scenarios with different alerting strategies. In addition, the visual distance estimation method was used to quantitatively analyze similar tendencies between the subject's perceived IAQ and concentration of IAP for each scenario. The experimental results confirmed that when an alerting notification was not sent, the occupants could not clearly perceive IAQ as the visual distance was the highest at 0.332. On the other hand, when the alerting notification whether the concentration of IAP exceeded the standard or not was sent, the occupants could perceive IAQ relatively clearly as the visual distance was reduced to 0.291 and 0.236. In conclusion, not only installing a monitoring device but also establishing proper alerting strategies on the concentration of IAP is essential to facilitate occupants' IAQ perception and protect occupants' health.

Analysis of ways to reduce potential health risk from ultrafine and fine particles emitted from 3D printers in the makerspace.

Due to the growing maker culture, maker spaces using multiple fused deposition modeling (FDM)-3D printers have spread around the world. However, the 3D printing process is known to cause the release of ultrafine and fine particles, which may have adverse health effects on occupants. Therefore, this experiment-based study was conducted on FDM-3D printers placed in an actual makerspace by the following three scenarios: the number of operating FDM-3D printers, ventilation, and measurement location to compare the concentrations of ultrafine and fine particles. In addition, the deposited dose in alveolar region for ultrafine and fine particles was predicted using a respiratory deposition model to analyze the potential health risk on occupants. As a result, the scenario-based comparison revealed that if the number of operating 3D printers is reduced by less than half, the potential health risk can be decreased by 34.1%, proper ventilation can reduce potential health risk by 55.5%, and working away from the 3D printer can also reduce potential health risk by up to 27.5%. This study analyzed the potential health risk of multiple FDM-3D printers on users in an actual makerspace, and proposed various improvement measures to reduce the potential health risk of ultrafine and fine particles.

Emotional impact, task performance and task load of green walls exposure in a virtual environment.

As the time spent indoors increases significantly due to the Coronavirus Disease 2019 (COVID-19) pandemic, creating an indoor environment to promote the health of occupants has become critical. Although green walls efficiently realize a healthy indoor environment, few studies have analyzed their impact on occupants based on the visual element of green walls. This study measures the emotional impact, task performance, and task load of the subjects according to four virtual experiments (a non-green wall, a freestanding green wall, two freestanding green walls, and a full-sized green wall). The results of the four experiments are as follows: (i) The visual elements of the green wall had an emotional impact on the occupants, which was verified through the Friedman test; (ii) the effect of the visual elements of the green wall on the task performance of the occupants was not verified by the one-way repeated measures analysis of variance (ANOVA); and (iii) the task load of the occupants influenced their task performance, which was verified by the repeated-measures ANOVA. This study can help determine the optimal type and area of green walls by considering their impact on the occupants as well as on the economic and constructional aspects of the indoor space.

Changes in energy consumption according to building use type under COVID-19 pandemic in South Korea.

An unprecedented global lockdown has been implemented for controlling the spread of COVID-19 in many countries. These actions are reducing the number of coronics, but with the prolonged COVID-19 outbreak, the restrictions on the activities of people are having a significant impact on all industries. Accordingly, this study aimed to statistically analyze changes in building energy consumption under the COVID-19 pandemic in South Korea, as well as identify the relationship between COVID-19 and building energy consumption according to the building use type. As a result, the average rate of changes in electricity and gas energy consumption decreased -4.46% and -10.35%, respectively, compared to the previous year. The energy consumption in most facilities has tended to decrease while energy consumption in residential facilities increased during COVID-19. The rate of change in building energy consumption had a significantly positive correlation with COVID-19 related factors in various facilities (e.g., neighborhood, religious, educational, and research facilities). Significant findings of this study that social distancing by the COVID-19 outbreak, has changed energy consumption according to building use type indicates the need for new energy systems to effectively manage the energy demand at the community level in the Post COVID-19 era.