University of California Transportation Center

This paper provides preliminary evidence that the placement of buildings influences the concentration of fine particulates by altering wind flow. The authors collected measurements of fine particulate concentration, wind speed, wind direction, and traffic levels around five Southern California arterials selected to represent a range of building densities. In some cases the difference in average concentrations between opposite sides of the street was on the order of 10 μg/m3. In most cases the concentration was higher on the upwind side of the street, where the wind wakes of buildings limit the dispersion of particulates. Although this work is exploratory in nature, it reveals that fine particulate concentrations can vary even within a single city block, a scale finer than those used in current policy models. Given the trend towards infill development and densification in many places, this is an important topic that warrants further research to more fully understand the influence of the built environment on air quality.