Shipping particle number emission is important as it can influence cloud condensation nuclei abundance and thus indirectly affect clouds and perturb the Earth's radiation budget. Here, we integrate a size-resolved Advanced Particle Microphysics module with a photochemical BOX MOdeling eXtension to the Kinetic PreProcessor and employ the resulting model to understand the microphysical and chemical characteristics of ship plumes. Simulated concentrations of key gaseous species and particle numbers are in good agreement compared with measurements from the NOAA Intercontinental Transport and Chemical Transformation (ITCT) 2K2 field study off the California coast. Further analysis reveals that significant new particle formation can occur in the plume and the growth of these secondary particles to 5–20 nm generally dominates the total particle numbers. We show that wind speed, emission rates of SO₂ and NO_x, solar irradiation, ambient temperature, and background [NH₃] have strong nonlinear effects on the ship particle number emission index (EIPN). Depending on the ambient air and meteorological conditions, the model simulations show that EIPN can range from ∼2.5 × 10¹⁴ no. kg⁻¹ fuel (dominated by primary particles) to ∼3.0 × 10¹⁸ no. kg⁻¹ fuel (dominated by secondary particles). In consideration of the current worldwide expansion of Emission Control Areas, we systematically study how the EIPN decreases with reduction of fuel sulfur content to 0.1%. Our study highlights the necessity of accounting for the nonlinear dependence of secondary particle formation on key controlling parameters in calculating shipping particle number emissions, which is important for determining aerosol indirect climate effects.

中文翻译：

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关于船舶粒子数排放指数：尺寸分辨微物理和关键控制参数

运输粒子数发射很重要，因为它可以影响云凝结核的丰度，从而间接影响云并扰乱地球的辐射收支。在这里，我们将尺寸分辨的高级粒子微物理模块与光化学 BOX 建模扩展集成到动力学预处理器中，并利用生成的模型来了解船舶羽流的微物理和化学特性。与 NOAA 洲际传输和化学转化 (ITCT) 2K2 加利福尼亚海岸外场研究的测量结果相比，关键气体物质和粒子数的模拟浓度非常一致。进一步的分析表明，羽流中可能会出现大量的新粒子形成，这些次级粒子增长到 5-20 nm 通常在总粒子数中占主导地位。我们表明风速，SO 的排放率₂和 NO _x、太阳辐射、环境温度和背景 [NH ₃ ] 对船舶粒子数排放指数 (EIPN) 具有很强的非线性影响。根据环境空气和气象条件，模型模拟表明 EIPN 的范围可以从 ∼2.5 × 10 ¹⁴ no. kg ^-1燃料（以初级粒子为主）到~3.0 × 10 ¹⁸ no. 公斤^-1燃料（以次级粒子为主）。考虑到目前世界范围内排放控制区的扩张，我们系统地研究了 EIPN 如何随着燃料硫含量降低到 0.1% 而降低。我们的研究强调了在计算运输粒子数排放时考虑二次粒子形成对关键控制参数的非线性依赖性的必要性，这对于确定气溶胶间接气候影响很重要。