Dry Particulate Nitrate Deposition in China

A limited number of ground measurements of dry particulate nitrate deposition (NO3-) makes it difficult and challenging to fully know the status of the spatial and temporal variations of dry NO3- depositions over China. This study tries to expand the ground measurements of NO3- concentrations at monitoring sites to a national scale, based on the Ozone Monitoring Instrument (OMI) NO2 columns, NO2 profiles from an atmospheric chemistry transport model (Model for Ozone and Related chemical Tracers, version 4, MOZART-4) and monitor-based sources, and then estimates the NO3- depositions on a regional scale based on an inferred model. The ground NO2 concentrations were first derived from NO2 columns and the NO2 profiles, and then the ground NO3- concentrations were derived from the ground NO2 concentrations and the relationship between NO2 and NO3- based on Chinese Nationwide Nitrogen Deposition Monitoring Network (NNDMN). This estimated dry NO3- depositions over China will be helpful in determining the magnitude and pollution status in regions without ground measurements, supporting the construction plan of environmental monitoring in future.