Effects of Meteorology, Emissions, and Regional Transport on Atmospheric Nr Deposition in Lake Taihu, China

Here, we applied WRF-CMAQ and its source apportionment module to investigate the interannual change and main drivers of atmospheric Nr deposition by species and form over Lake Taihu during 2017–2020. The annual average of Nr deposition was estimated at 6.55 ± 0.18 Gg N yr^–1, and reduced nitrogen (RDN) accounted for 70% resulting from abundant NH₃ emissions from agricultural activities and continuous NO_<i>x</i> controls in the Basin.

Meteorological factors played a greater role than emission abatement in driving the interannual variability of Nr deposition for both summer and winter. Long-range transport from outside of the basin became an increasingly important contributor to oxidized nitrogen (OXN) deposition, partly offsetting the benefits of local NO_<i>x</i> controls. Upwind cities were identified with greater contributions to Nr deposition in winter, whereas the circulation pattern strongly affected the contributions of cities in summer.