A spatial analysis of ozone and PM2.5 distribution for assessing design factors of healthy buildings

Indoor air quality (IAQ) represents one of the significant challenges in healthy building design, with thermal comfort and daylighting being primary design objectives. This study aims to demonstrate the potential of energy-independent building infrastructure as a passive design solution to mitigate the impact of outdoor air pollution. This paper presents experimental and numerical investigations to establish the relationship between design factors (e.g., building orientation, geometry, and window opening location) and the spatial distribution of ozone and fine particulate matter (PM2.5) in residential houses. Our case study involves experimentally validated computational fluid dynamics (CFD) simulations for typical rowhouse archetypes in one of the United States' most polluted cities. Our findings indicate that higher ozone levels are observed on upper floors, posing a significant exposure risk at a breathing zone height of 1.7 m. In contrast, PM2.5 levels are most concerning at a height of 1 m, directly impacting children's health. Alarmingly, future trends of ozone pollution suggest that these risks could be almost three times higher compared to current conditions. Given the distinctive diurnal patterns of outdoor air pollution, the study also finds that the strategic placement of windows for nighttime air flushing, specifically in the upper two-thirds of the building, can improve IAQ. Our analysis of the spatial placement of the air purifier reveals that the optimal location is at the middle center of the windward wall. Our work underscores the potential of building design features in mitigating pollution exposure in indoor environments, emphasizing the importance of architectural solutions in public health.