EVALUATING NO₂ COLUMN VARIATIONS OVER UPPER NORTHERN THAILAND AND PARTICULARLY LAMPANG PROVINCE TO ASSESS THE IMPACT OF AIR QUALITY USING SATELLITE AND GROUND DATA

Abstract

This study assesses NO₂ column variations over upper northern Thailand using satellite data. The study examined seasonal variable and spatial distribution, both horizontally and vertically, by tracking satellite-based nitrogen dioxide (NO2) and particular matter (PM2.5) and ground-level data. Since the ground-based NO₂ monitoring stations are limited across the region, satellite-based observations serve as a valuable alternative. This approach helps clarify relevant vertical air quality issues, identify regions that are the most vulnerable to poor air quality, and clarifies the main source of air pollution in different seasons.

The findings show that air pollution in the region is mainly influenced by anthropogenic activities such as industrial emission, transportation, and agricultural waste burning. Additionally, forest fires and agricultural burning during the dry season represented a significant natural hazard contributing to poor air quality. In addition, geographical and meteorological factors also affect the persistence and dispersion of pollutants. Seasonal analysis indicated that NO2 column amount peaked during the hot season, coinciding with the second maize harvesting period and the forest fire season. In contrast, pollutant levels declined significantly during the rainy season due to wet deposition, while moderate concentrations persisted around urban and industrial zones, including the Mae Moh power plant. During the cold season, stagnant air led to pollutant accumulation in low-lying valleys.

Finding potential sources or contributing factors is essential for supporting more effective air pollution control strategies, apart from simply focusing on controlling burning. A more comprehensive approach to industrial emission control is needed, one that is not only large industries but also small and medium-scale factories. In addition, an integrated strategy that includes increasing law enforcement, public awareness, promoting ground-based monitoring stations near industrial area, enhances continued assessment of NO2 to improve understanding of related pollutants such as PM2.5 and ground-level ozone (O3).

This scientific evaluation of different pollutants underscores the necessity of proactive risk management strategies to support sustainable environmental management and enhance public well-being.