Analysis of Long-term Trends in Asian Aerosol Optical Depth Using Ground-based Observational Data

Aerosols play a crucial role in affecting air quality, climate change, and public health. They show significant differences in concentration across regions and fluctuate over time. Therefore, it's essential to examine long-term changes in aerosol levels and analyze the associated patterns to improve air quality and advance climate change research. This study specifically looks at the long-term trends of Aerosol Optical Depths (AODs) in Asia and compares the trends of Fine-mode Aerosol Optical Depths (FAODs) and Coarse-mode Aerosol Optical Depths (CAODs). AOD indicates how much solar radiation is blocked by aerosols in the atmosphere, serving as an important measure of aerosol quantity. The Aerosol Robotic Network (AERONET) is a ground-based observation network providing detailed information on aerosol properties globally. AERONET has extensive long-term data and ensures continuous observations through daily measurements. Consequently, we analyzed the prolonged trends of AOD using AERONET data. To understand changes in aerosol quantity from human-made sources and natural events like yellow dust, we examined trends in Coarse-mode Aerosol Optical Depths (CAODs) and Fine-mode Aerosol Optical Depths (FAODs), categorizing aerosols by size. By comparing CAODs and FAODs, we identified consistent trends in the analysis across countries or sub-regions. This analysis highlights significant regional differences in aerosol concentrations, influenced by factors such as the local environment and air quality policies of each country.