Structural Causality Between Road Traffic and Particulate Matter Concentrations in Urban Areas

Abstract

Road traffic makes a major contribution to air pollution by emitting solid and liquid particles, also known as particulate matter, into the air. However, the causal relationship between road traffic and particulate matter emissions has not been adequately explored, primarily because traffic is the result of dynamic interactions involving many real-time variables, such as volume and speed. This study used structural equation modeling to quantify this complex causal relationship. A one-year survey using a mobile laboratory was conducted to collect data on particulate matter concentrations and traffic, which were then combined with weather statistics provided by the Korea Meteorological Administration. The key finding of this study suggests that greater attention in research and policy should be directed toward non-exhaust particulate matter emissions from road traffic.