Simulation of PM2.5 Concentrations around the Proposed Yangon Outer Ring Road (Eastern Section) in Myanmar Using CALINE 4 Model

An increase in traffic volume has resulted in the deterioration of environmental quality and human health in Yangon as well as in the surrounding areas that are connected to the city via several road links. The Yangon Outer Ring Road Construction (YORR) (Eastern Section) is a priority project for solving traffic-related problems. This study aimed to simulate the current levels of PM2.5 concentration around the proposed YORR (Eastern Section) area using the CALINE 4 model and to evaluate the model’s performance. Air quality measurements of PM2.5 were carried out in five townships around the proposed road construction area-for one week at each monitoring location-from January 24th to March 2nd, 2021 using the Haz-Scanner Environmental Perimeter Air Station. When compared to the ambient air quality guidelines of Myanmar, the International Finance Corporation, and the World Health Organization, the observed PM2.5 concentrations were found to be usually high at all locations, except in Kyauktan township. Statistical analysis indicated that the CALINE 4 model performed satisfactorily with a coefficient of determination of 0.85-0.90, fractional bias of 0.03-0.50, and normalized mean square error of 0.001-0.100. It is crucial that mitigation measures, including policies regarding the use of low PM emission vehicles and road-side barriers, be implemented by regulatory authorities during and after the YORR construction.