The nucleation mechanism involving amines is crucial for wintertime new particle formation in China. This study incorporated the gaseous sulfuric acid (SA)–dimethylamine (DMA) nucleation mechanism and amine physicochemical parameterization into the WRF-Chem model, developing a gridded amine emission inventory covering terrestrial anthropogenic and marine biological emissions (MBE) via multisource data (sea surface temperature, chlorophyll-a, sea surface salinity, NH3 column concentration, and wind speed) and 4-dimensional ensemble variational data assimilation algorithm. At the Gucheng site in the Beijing-Tianjin-Hebei region, sensitivity experiments showed the inventory improved particle number size distribution simulation, with nucleation rate correlation increasing from 0.69 to 0.81. Although the impact of MBE is limited by prevailing land-to-sea winds, a slight increase in amine concentrations (monomethylamine, 0.21%; DMA, 0.75%; trimethylamine, 1.7%) still led to a maximum 9.3% increase in particle number concentration, indicating that amines are efficient nucleation precursors and the role of MBE should not be neglected. The SA-DMA nucleation pathway significantly enhanced the mass concentration of submicron particles by promoting the gas-to-particle conversion of SA. However, its influence diminished with increasing particle size, as the subsequent growth of particles was likely driven by more complex organic compounds such as aromatic hydrocarbons.
Zhang et al. (Thu,) studied this question.