Hygroscopic growth of common organic aerosol solutes, including humic substances, as derived from water activity measurements

摘要: [1] Studies have shown that organic matter often constitutes up to 50% by mass of tropospheric aerosols. These organics may considerably affect the water uptake properties these aerosols, impacting Earth's climate and atmosphere. However, considerable uncertainties still exist about hygroscopic carbon (OC) in particles. In this study, we assembled an apparatus measure equilibrium vapor pressure over bulk solutions. We used results calculate growth curve deliquescence relative humidity (DRH) representative compounds three OC categories: saccharides, mono/dicarboxylic acids, HULIS (Humic-Like Substances). To our knowledge, is first study examine means a method on such as fulvic humic acids. also explored temperature effect within 0°C–30°C range found no effect. The DRH obtained were excellent agreement with published tandem differential mobility analyzer (TDMA), electrodynamic balance, data for sodium chloride, ammonium sulfate, d-glucose, levoglucosan, succinic acid, glutaric acid. factor 1.0 at 90% phthalic, oxalic, humic, two acids; disagree various TDMA studies. widely particles but can be affected particle microstructural arrangements before inability fully dry Thus, future it will important confirm nondeliquescent alternate methods.