Decadal\nResponse of Atmospheric Inorganic Nitrogen\nDry Deposition into Offshore Areas to Policy Controls and Environmental\nSignificance

Accurately assessing the dry deposition\nfluxes of inorganic nitrogen\naerosol (aerosol-IN) is crucial for mitigating the ecological damage\ncaused by excessive nitrogen in oceanic equilibria. We developed a\ndry deposition model to assess the dry deposition fluxes of aerosol-IN\ninto Chinese offshore areas over a decade, with the range of 2.81\n× 10<sup>6</sup>–1.89 × 10<sup>7</sup> g N km<sup>–2</sup> year<sup>–1</sup>. Our findings showed a clear\ndecline in the dry deposition fluxes of aerosol-IN following the implementation\nof environmental laws and policies. Promoting cleaner production,\nusing new energy vehicles, the rational use of nitrogenous fertilizers,\nand standardized straw burning will all reduce pollution caused by\nexcessive nitrogen deposition. High ratios of dry deposit to river\ntransport nitrogen (0.48–17.89) indicate aerosol-IN is a significant\nsource of inorganic nitrogen in Chinese offshore areas. The implementation\nof the policy has significantly reduced aerosol-IN deposition into\nthe ocean, but its contribution remained substantial and should be\nconsidered when protecting the Chinese marine ecological environment.