Inhibition of efflorescence in mixed organic-inorganic particles at temperatures less than 250 K studied with optical microscopy

Field measurements have shown that mixed organic-inorganic particles are abundant in the atmosphere. Understanding the deliquescence and efflorescence properties of these particles is important for predicting the role these particles play in climate and atmospheric chemistry. Recently the deliquescence and efflorescence properties of several types of mixed organic-inorganic particles have been studied at room temperature, but there have been very few studies at lower temperatures. This work examines the efflorescence trends of mixed organic-inorganic particles at temperatures ranging from 233 K and 298 K. The experimental approach involves an optical microscope coupled to a relative humidity controlled flow cell. The initial studies, which focused on citric acid-ammonium sulfate particles, suggest that efflorescence of some types of mixed organic-inorganic particles is inhibited at temperatures less than 250 K.