Atmospheric aerosol particles are commonly complex, aqueous organic-inorganic mixtures, and accurately predicting the properties of these particles is essential for air quality and climate projections. The prevailing assumption is that aqueous organic-inorganic aerosols exist predominately with liquid properties and that the hygroscopic inorganic fraction lowers aerosol viscosity relative to the organic fraction alone. Here, in contrast to those assumptions, we demonstrate that increasing inorganic fraction can increase aerosol viscosity (relative to predictions) and enable a humidity-dependent gel phase transition through cooperative ion-molecule interactions that give rise to long-range networks of atmospherically relevant low-mass oxygenated organic molecules (180 to 310 Da) and divalent inorganic ions. This supramolecular, ion-molecule effect can drastically influence the phase and physical properties of organic-inorganic aerosol and suggests that aerosol may be (semi)solid under more conditions than currently predicted. These observations, thus, have implications for air quality and climate that are not fully represented in atmospheric models.

大气气溶胶颗粒通常是复杂的有机无机混合水溶液，因此准确预测这些颗粒的性质对于空气质量和气候预测至关重要。普遍的假设是，水性有机-无机气溶胶主要以液体性质存在，并且吸湿性无机组分相对于单独的有机组分降低了气溶胶粘度。在这里，与这些假设相反，我们证明了增加的无机物含量可以增加气溶胶粘度（相对于预测），并通过协同的离子-分子相互作用实现湿度相关的凝胶相变，从而引起与大气相关的低浓度的长距离网络。 -氧化有机分子（180至310 Da）和二价无机离子。这个超分子的 离子分子效应可以极大地影响有机-无机气溶胶的相和物理性质，并表明在比目前预期的更多的条件下，气溶胶可能为（半）固体。因此，这些观察结果对空气质量和气候有影响，而在大气模型中并未完全体现出来。