How May Building Morphology Influence Pedestrians’ Exposure to PM2.5?

Abstract

Due to their sparse distribution and placement in open areas, fixed air-quality-monitoring stations fail to characterize the effect of contextual factors such as buildings on the dispersion of PM2.5. This study evaluated the effects of building morphology on PM2.5 dispersion in a pedestrian-friendly area on the University of Texas at Dallas campus, spanning approximately 0.5 km2. The study collected PM2.5 data along five distinct paths exhibiting varying building morphological characteristics in terms of size, height, density, and spacing at a high spatial resolution. The interquartile range of PM2.5 levels across nine data-collection runs varied from 0.3 µg/m3 to 1.7 µg/m3, indicating relatively uniform PM2.5 levels within the study area. Furthermore, weather-related variables played a dominant role in PM2.5 distribution as temporal variation over-powered spatial variation in the PM2.5 data. The study employed a fixed-effects model to assess the effect of time-invariant morphological characteristics of buildings on PM2.5 and found that the buildings’ morphological characteristics explained 33.22% variation in the fixed effects in the model. Furthermore, openness in the direction of wind elevated the PM2.5 concentration.