Studies of the land-sea-air interactions of aerosol are scarce considering their significant role in global environmental changes. Here, we investigated potential sources of sub-micron aerosols over the East Sea (Sea of Japan), which is strongly influenced by continental and marine aerosols. A high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) was used to measure the size-resolved chemical compositions of sub-micron aerosols during the period March 10–15, 2020. Concentrations of all AMS species, black carbon (BC), PM₁₀ (particulate matter <10 μm) and PM_2.5 (particulate matter <2.5 μm) were higher when cruising in industrialized coastal areas compared to the offshore region. A positive matrix factorization (PMF) model identified five distinct sources, i.e., hydrocarbon-like organic aerosol, semi-volatile and low-volatile oxygenated aerosols, methanesulfonic acid (MSA), and dimethyl sulfide (DMS; C₂H₆S) oxidation, which accounted for 5.98 %, 21.6 %, 28.3 %, 34.5 %, and 9.64 % of the total organic mass, respectively. The spatiotemporal variation of MSA, as well as the MSA to sulfate ratio (MSA:SO₄²⁻) over the East Sea, was determined for the first time. The mass concentrations of MSA displayed a similar time series distribution pattern to those of DMS. The time series distributions of the MSA:SO₄²⁻ ratio displayed distinct differences, with higher ratios downwind of the ocean (0.216 ± 0.083 μg·m⁻³) than land (0.089 ± 0.030 μg·m⁻³). The growth of ultrafine particles (10–35 nm) was observed during two of the elevated MSA:SO₄²⁻ ratio events, suggesting a potential role of MSA in new particle formation.

考虑到气溶胶在全球环境变化中的重要作用，对气溶胶的陆-海-气相互作用的研究很少。在这里，我们调查了受大陆和海洋气溶胶强烈影响的东海（日本海）上亚微米气溶胶的潜在来源。高分辨率飞行时间气溶胶质谱仪 (HR-ToF-AMS) 用于测量 2020 年 3 月 10 日至 15 日期间亚微米气溶胶的尺寸分辨化学成分。所有 AMS 物种的浓度，黑碳 (BC)、PM ₁₀（颗粒物 <10 μm）和 PM _2.5与近海地区相比，在工业化沿海地区巡航时（颗粒物 <2.5 μm）更高。正矩阵分解 (PMF) 模型确定了五个不同的来源，即类烃有机气溶胶、半挥发性和低挥发性含氧气溶胶、甲磺酸 (MSA) 和二甲基硫醚 (DMS；C ₂ H ₆ S) 氧化, 分别占总有机质量的 5.98%、21.6%、28.3%、34.5% 和 9.64%。首次确定了东海MSA 的时空变化以及 MSA 与硫酸盐的比率 (MSA:SO ₄ ^{2− )。}MSA 的质量浓度显示出与 DMS 相似的时间序列分布模式。MSA:SO 的时间序列分布₄ ²⁻比值表现出明显差异，海洋下风向（0.216 ± 0.083 μg·m ^－3）高于陆地（0.089 ± 0.030 μg·m ^－3）。在两个升高的 MSA:SO ₄ ²⁻比率事件中观察到超细颗粒 (10–35 nm) 的生长，表明 MSA 在新颗粒形成中的潜在作用。