Roadside Air Quality Simulation Model for Urban Main Roads in Japan Clean Air Program (II) Case Study; Effect of Traffic Volume Reduction and Idle Stop on Roadside Air Quality

• Published in: Journal of Japan Society for Atmospheric Environment / Taiki Kankyo Gakkaishi Vol. 38; no. 5; pp. 287 - 300
• Main Authors: YOSHIKAWA, Yasuo, HAYASHI, Seiji, HIRAI, Hiroshi, UEHARA, Kiyoshi
• Format: Journal Article
• Language: English; Japanese
• Published: Japan Society for Atmospheric Environment 10.09.2003
• Subjects: emission estimation; idle stop; roadside air quality; simulation model; street canyon; traffic volume reduction
• ISSN: 1341-4178; 2185-4335
• DOI: 10.11298/taiki1995.38.5_287

A case study to investigate the effect of traffic volume reduction and idle stop on NOx emission and concentration distribution along main roads was conducted using the Roadside Air Quality Simulation Model reported in the first paper. Vehicle speed profile and NOx emission distribution, averaged over all vehicles passing through the road links, were calculated by the traffic simulation model and the transient emission estimation model. In the Base Case, average speed shows a “V” shape whose bottom is locates at the stop line of the crossroads, and the emission rate increased toward the stop line along the road at the upstream side of the crossroads. NOx concentration, show high values at spots where stationary vortexes occur behind buildings or near corner of the crossroads. In the case of Traffic Volume Reduction, NOx emission was reduced at most locations of the road links due to reduction of vehicle number and resulting increase of travel speed. In the case of Idle Stop, NOx emission decreased largely at the upstream side of the crossroads where vehicles stop due to traffic signal. Also, quantitative estimation of concentration profile against wind direction and 1-day averaged concentration at a vehicular emission monitoring station was conducted. Through this case study, applicability of the Roadside Air Quality Simulation Model on the quantitative study of air quality was verified.