The hygroscopic properties of the organic fraction of aerosols are poorly understood. The ability of organic aerosols to absorb water as a function of relative humidity (RH) was examined using data collected during the 1999 Big Bend Regional Aerosol and Visibility Observational Study (BRAVO). (On average, organics accounted for 22% of fine particulate matter with an aerodynamic diameter less th...

Effects of highly hygroscopic sorbitol, citric acid, sodium carboxymethyl cellulose or polyvinylpolypyrrolidone, on the hydrolysis of simvastatin in tablets at 25°/90% RH were studied. The simvastatin tablets were prepared by direct powder compression. Simvastatin and its hydrolyte, simvastatin acid, were quantitatively analysed by high performance liquid chromotography. The hygroscopicity, wat...

The hygroscopic behavior of atmospheric aerosols has a significant effect on the global climate change. In this study, a physisorption analyzer was used to measure the water adsorption capacity of Al(2)O(3), NaCl, NH(4)NO(3), and (NH(4))(2)SO(4) particles at 273.6 K. Qualitative and quantitative information about water adsorption on these particles was obtained with changing the temperature and...

A series of experiments has been conducted in the Caltech indoor smog chamber facility to investigate the water uptake properties of aerosol formed by oxidation of various organic precursors. Secondary organic aerosol (SOA) from simple and substituted cycloalkenes (C5-C8) is produced in dark ozonolysis experiments in a dry chamber (RH∼5%). Biogenic SOA from monoterpenes, sesquiterpenes, and oxy...

The volatile and hygroscopic properties of ammonium sulphate seeded and unseeded secondary organic aerosol (SOA) derived from the photo-oxidation of atmospherically relevant concentrations of α-pinene were studied. The seed particles were electrospray generated ammonium sulphate ((NH4)2SO4) having diameters of approximately 33 nm with a quasi-mono-disperse size distribution (geometric standard ...

Airborne mineral dust particles serve as cloud condensation nuclei (CCN), thereby influencing the formation and properties of warm clouds. It is therefore of atmospheric interest how dust aerosols with different mineralogy behave when exposed to high relative humidity (RH) or supersaturation (SS) with respect to liquid water. In this study the subsaturated hygroscopic growth and the supersatura...

In this study, the influence of pH on moisture-absorbing swelling cracks red mudstone in southwest China was studied and its microscopic mechanism revealed. A self-designed water absorption device combined with digital speckle correlation (DSCM), scanning electron microscope, XRD diffraction experiment, mercury injection experiment other means were used. The results indicated that compared an a...