Decadal Response of Atmospheric Inorganic Nitrogen Dry Deposition into Offshore Areas to Policy Controls and Environmental Significance

Accurately assessing the dry deposition
fluxes of inorganic nitrogen
aerosol (aerosol-IN) is crucial for mitigating the ecological damage
caused by excessive nitrogen in oceanic equilibria. We developed a
dry deposition model to assess the dry deposition fluxes of aerosol-IN
into Chinese offshore areas over a decade, with the range of 2.81
× 106–1.89 × 107 g N km–2 year–1. Our findings showed a clear
decline in the dry deposition fluxes of aerosol-IN following the implementation
of environmental laws and policies. Promoting cleaner production,
using new energy vehicles, the rational use of nitrogenous fertilizers,
and standardized straw burning will all reduce pollution caused by
excessive nitrogen deposition. High ratios of dry deposit to river
transport nitrogen (0.48–17.89) indicate aerosol-IN is a significant
source of inorganic nitrogen in Chinese offshore areas. The implementation
of the policy has significantly reduced aerosol-IN deposition into
the ocean, but its contribution remained substantial and should be
considered when protecting the Chinese marine ecological environment.