The effects of meteorology and biomass burning on urban air quality: The case of Bangkok

Abstract

Bangkok, one of the biggest metropolitan cities in Asia, has been experiencing poor (PM10 > 50 μg/m3 annual average) air quality for decades. Major sources of air pollution are traffic emissions, biomass burning, and non-combustible sources. In this study, the impact of meteorology and biomass burning on the concentration of particulate matter was assessed. Data from three monitoring stations and remotely sensed fire count between 2017 and 2020 was used to investigate the association. Moreover, the spatiotemporal pattern of aerosol optical depth (AOD) and fire count derived from remotely sensed data were investigated to observe their association. This study found that temperature, relative humidity, rainfall, wind speed, and wind direction have a significant negative relationship with particulate matter concentration. In contrast, atmospheric pressure and fire count have a significant positive correlation with particulate matter concentration. Moreover, the pollution rose diagram for particulate matter indicated that the northeasterly wind is the prevailing wind direction that carries the most pollutants. Furthermore, the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model and AOD indicated that biomass burning in neighboring regions significantly (p < 0.05) affected the particulate matter concentration in Bangkok. Multiple linear regression (MLR) analysis established that atmospheric pressure has the highest negative impact on the city air quality, followed by biomass burning, while heavy rainstorms were the most substantial parameter that reduced particulate matter concentration. Taken together, these findings highlight the importance of meteorological factors in understanding air pollution mechanisms in Bangkok. Equally important, the insights gained from this study may assist in addressing the long-range transport of air pollutants from biomass burning, which requires a coordinated engagement with neighboring countries.