Bangkok port and coastal regions of Thailand under atmospheric PM2.5 pollution: A hypothetical nuclear power plant accident

Abstract

The atmospheric transport pathways of 1) a hypothetical accident of aerosol at Ninh Thuan Nuclear Power Plant (NPP) in Vietnam to the coastal area of Thailand and 2) the source of PM2.5 near the area of Bangkok port were selected for case studies. The overviews of atmospheric transport patterns were analyzed using the long-term mean wind and the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model for simulating the transport pathway. The results found that the possible pathway of aerosol from Ninh Thuan NPP to coastal regions of Thailand was present over the entire year, except for the southwest monsoon month. The percentage of aerosol transport reaching the coast of Thailand is highest in the southern coastal part, found in January-April and October-December, with a maximum in January (approximately 84 %). For PM2.5 pollutants on a poor day, strongly positive and negative significant relationships with relative humidity (RH) (r = 0.44, rs = 0.46) and wind speed (r = -0.46, rs = -0.47) were found, respectively. The concentration of PM2.5 is slightly negatively correlated with wind direction. In addition, the upper air transport may bring PM2.5 pollutants from neighboring provinces or Southeast Asia to Bangkok port, Thailand, which appeared in anticyclone form in the upper atmosphere before the day which exceeded the safety level of PM2.5. Highlights The possible pathway of aerosol from Ninh Thuan NPP to coastal regions of Thailand is present over the entire year The percentage of aerosol transport from Ninh Thuan NPP reaching the coast of Thailand is highest in the southern coastal part during the northeast monsoon The exceeding air pollution problem in Bangkok comes from unfavorable meteorological conditions The anticyclone center in the upper atmosphere of Vietnam, Laos, and Cambodia formed before the day, which exceeded the safety level at a poor level