Evaluation of Spatial and Temporal Air Quality Variation in Southern Vietnam Using Multivariate Statistical Approaches

The study aims to assess the air quality and identify polluting sources in the southern Vietnam using eight air variables of temperature, humidity, wind speed, pressure, noise, total suspended particulates (TSP), sulfur dioxide (SO2), nitrogen dioxide (NO2) at 30 stations in eight monitoring periods (April–December) in 2020. Correlation and principal components and cluster analyses were applied in the study. Air quality in traffic and urban areas were identified with the highest pollutant concentrations. Concentrations of air pollutants were dependent on sources of impact but not the seasons. Noise was positively correlated with vehicle density and exceeded the permissible limit of QCVN 26:2010/BTNMT. TSP was found high in urban areas. Air contaminants were positively mutual correlation, while it was negatively correlated with meteorological factors. PCA (Principal Component Analysis) could explain respectively 81.2% and 83.4% of the total variance of spatial and temporal variation of air quality. The main sources of air pollutant could be from transportation, residential areas, industrial production and solid waste treatment plants. Cluster Analysis (CA) has formed five clusters of monitoring stations with similar air quality from 30 original stations. At the same time, the initial 8 observation periods were also grouped into four clusters. Thereby, the monitoring program in this study area could be reduced to four times/year with 25 monitoring locations.