Analysis of the spatiotemporal variability of SO2 and NO2 in ambient air in Quang Ninh Province using statistical and GIS-based methods

Abstract

This study aims to analyze the spatiotemporal distribution of SO₂ and NO₂ in ambient air in Quang Ninh Province using statistical methods and GIS. The dataset consists of measurements collected from 62 monitoring sites across the province in February, April, June, August, October, and December of 2024. The results show that annual mean SO₂ concentrations ranged from 28.1 to 32.8 µg/Nm³, with an overall average of 31.1 µg/Nm³, while annual mean NO₂ concentrations ranged from 19.4 to 25.2 µg/Nm³, with an overall average of 22.4 µg/Nm³. No monitoring site exceeded the annual limits specified in QCVN 05:2023/BTNMT for either pollutant. Temporally, both SO₂ and NO₂ showed a slight increase toward the end of the year, particularly in December. Spatially, SO₂ concentrations were relatively higher in the western and southwestern parts of the province, where industrial activities, coal mining, and thermal power plants are concentrated, whereas NO₂ was more strongly associated with urbanized and traffic-intensive areas. The Trend Analysis results suggest weak spatial trends, especially for SO₂. These findings provide a scientific basis for air quality monitoring and environmental management in Quang Ninh Province.