Particulate Matter Exposure at a Densely Populated Urban Traffic Intersection and Crosswalk

TL;DR

This study investigates particulate matter exposure for pedestrians at an urban traffic intersection, analyzing variations in PM levels and assessing exposure risks to inform pollution reduction policies.

Contribution

It provides detailed measurements of PM dispersion and pedestrian exposure at a busy intersection, highlighting the importance of targeted pollution mitigation strategies.

Findings

PM levels vary significantly across traffic signal cycles

Pedestrian exposure to PM is higher during certain journey segments

Weather conditions influence PM dispersion and pedestrian exposure

Abstract

Exposure to elevated particulate matter pollution is of great concern to both the general public and air quality management agencies. At urban traffic intersections, for example, pedestrians are often at a higher risk of exposure to near-source PM pollution from traffic while waiting on the roadside or while walking in the crosswalk. This study offers an in-depth investigation of pedestrian exposure to PM pollution at an urban traffic intersection. Fixed-site measurements near an urban intersection were conducted to examine the variations in particles of various sizes through traffic signal cycles. This process aids in the identification of major PM dispersion patterns on the roadside. In addition, mobile measurements of pedestrian exposure to PM were conducted across six time intervals that correspond to different segments of a pedestrian's journey when passing through the intersection. Measurement results are used to estimate and compare the cumulative deposited doses of PM by size categories and journey segments for pedestrians at an intersection. Furthermore, comparisons of pedestrian exposure to PM on a sunny day and a cloudy day were analyzed. The results indicate the importance of reducing PM pollution at intersections and provide policymakers with a foundation for possible measures to reduce pedestrian PM exposure at urban traffic intersections.