To reveal the relationship between nitrogen deposition and carbon sink capacity in coastal wetlands of East Asia, the atmospheric chemical transport models were used in this study. We found that mangroves gained the most, capturing about 6.5 g C m^-2 in summer but less than 0.1 g C m^-2 in winter. The study shows pollution management must follow seasonal and local needs to keep wetlands working as strong natural carbon stores and guide better coastal protection in East Asia.