Road Traffic Flow and Air Pollution Concentrations: Evidence from Japan

Author Name NISHITATENO Shuhei (Research Associate, RIETI) / Paul J. BURKE (Australian National University) / ARIMURA Toshi H. (Faculty Fellow, RIETI)
Creation Date/NO. April 2023 23-E-031
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Vehicular emissions, being a major global health concern, have gathered worldwide attention and necessitated extensive research to gain deeper insights. The aim of this study was to estimate the effects of road traffic flow on the local ambient concentrations of nitrogen oxides (NOx), carbon monoxide (CO), non-methane hydrocarbons (NMHC), and fine particulate matter (PM2.5) in Japan. We constructed an hourly panel dataset of nationwide samples of air pollution monitoring stations from 2010–2015. By estimating a dynamic panel model with station-hour panel data, short-run pollution-road traffic elasticities of 0.04–0.05 for NOx, CO, and NMHC, and long-run elasticities of 0.09–0.17 were observed; however, no significant evidence was found for PM2.5. We used these estimates to understand the potential effects of reducing road traffic flow to meet the World Health Organization’s new air quality guidelines.