Estimations of the contribution of nitrate emissions to the total burden of aerosols in major cities of Asia from the Pandora Asia Network

Since the 21st century, the importance of fine-mode particles associated with NO₂ has become increasingly prominent on a global scale, driven by reductions in SO₂ emissions. NO₂, sharing emission sources with aerosols, acts as a precursor for secondary aerosol formation through atmospheric chemical reactions. Ground-based remote sensing measurements provide high temporal resolution of total burden air pollutants. This study analyzed the relationship between aerosol optical depth (AOD) and total column nitrogen dioxide (NO₂) from the Pandora instruments operated by the Pandonia Global Network (PGN) and Pandora Asia Network (PAN) to assess the contribution of the nitrate emissions to the aerosols. The daily coefficient of determination (DDC) between NO₂ vertical column density (VCD) and AOD was analyzed across various Asian cities. By incorporating water vapor (H₂O) VCD as a meteorological adjustment, a significant relationship between NO₂ VCD and adjusted DDC was observed, suggesting that in sites with high NO₂ loading, NO₂ is highly correlated with the AOD. Pandora’s simultaneous direct sunlight measurements of AOD, H₂O VCD, and NO₂ VCD provide valuable information on the relationship between atmospheric aerosols and trace gases, contributing to global air quality research.

 

Acknowledgements
This research was supported by Particulate Matter Management Specialized Graduate Program through the Korea Environmental Industry & Technology Institute(KEITI) funded by the Ministry of Environment (MOE).