AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Microcharacterization and Identification of Non-exhaust Particles from On-road Driving and Laboratory Measurements using SEM-EDX Analysis
SEOKHWAN LEE, Sunyoup Lee, Hongsuk Kim, Korea Institute of Machinery and Materials
Abstract Number: 546 Working Group: Urban Aerosols
Abstract In recent years, growing concern about climate change and air pollution has resulted in stringent legislative actions, such as limits for particulate matter (PM). To date, substantial reductions in traffic-related pollution have focused on exhaust emissions, but recent studies have reported that non-exhaust sources such as road dust, re-suspension of materials from the pavement surface, and wear of vehicular parts (tires, brakes, etc.) contribute as much as exhaust emissions to traffic related pollution.
Tire wear particles (TWPs) are a significant pollutant, especially as a source of zinc in the urban environment. Several studies have been conducted to investigate the characteristics of TWPs. They identified rubber particles from tire wear experiments in the laboratory and found Zn using SEM-EDX (Scanning Electron Microscope-Energy Dispersive X-ray Spectroscopy) analysis. They also determined the chemical composition of TWPs and reported that the coarser fractions generated by studded tires were dominated by Si, Ca, K, and Fe.
In addition to investigating tire-related particles, several authors have characterized brake wear particles (BWPs) emitted from the brake lining during vehicle deceleration in the laboratory. They determined mass size distributions and conducted a chemical analysis of BWPs in a closed chamber. They reported that the mode diameters of BWPs were <0.1 μm and >10 μm (bimodal), and Fe, Cu, Sb, and Ba were the most abundant elements.
This study characterizes the morphology and chemical composition of traffic-related non-exhaust particles from on-road driving (roadway particles) and laboratory measurements (TWPs and BWPs) using SEM-EDX analysis. The results show that coarser fractions generated by tires had multi angular morphology, and was dominated by Zn, S, Si, Al, Fe, and Mg. The BWPs consisted mainly particulates Cu, Ba, Sb, Fe, Zr, and mineral elements (Al, Ca, and K), and had round-edged morphology.