Assessing the Spatial Distribution of Traffic-Related Lung Deposited Surface Area in an Urban Micro-Environment Using Computational Fluid Dynamics
PO-KAI CHANG, Li-Ti Chou, Ta-Chih Hsiao,
National Taiwan University, Taiwan Abstract Number: 350
Working Group: Urban Aerosols
AbstractIn urban areas, traffic emission is a major contributor to particulate matter (PM), especially ultrafine particles (UFPs). The health impact of UFPs (particle size smaller than 100 nm) has been increasingly recognized because of their large number concentration and total surface area. Lung deposited surface area (LDSA) is defined as the total surface area of the particles deposited in the lung (a function of particle size) that has been argued to more accurately predict health effects from PM exposure. This study investigated the LDSA emitted from traffic sources in a Taiwan urban area and its potential health impacts, with a focus on UFPs. Field measurements revealed that traffic-related LDSA accounted for 63.5% of total LDSA, with a concentration of 28.1 (μm
2/cm
3). The study employed computational fluid dynamic (CFD) simulations to assess particle transmission and their health impacts. The gradient of LDSA concentration in the surrounding microenvironment was evaluated based on the simulation results, which showed that the spatial distribution of concentration was strongly affected by urban geometric structure. The high concentration were found in major traffic roads and the flow vortex positions. Generally, when the distance from the pollution source increased, the concentration would gradually decrease. Additionally, the study assessed the excess lifetime cancer risk (ELCR) associated with exposure to UFPs. This study provides important insights into the impacts of traffic-related air pollution on human health, and highlights the importance of addressing this issue through evidence-based policy interventions and sustainable urban planning.