Molecular state of sulfate aerosols in the remote Everest highlands

For the selective detection of the sulfuric acid component in individual submicron atmosphericaerosol particles, a new in situ approach using a vapor-deposited calcium thin film as a reactiveaerosol-collecting surface has been tested in field observations carried out in the remote Everesthighlands.It is found that in the remote Everest highlands, atmospheric aerosol particles in thesubmicron size range are mostly sulfate-contai&g particles in-the form of a hydrated sulfuricacid droplet and/or in the form of a supersaturated acidic sulfate solution droplet at ambientrelative humidity less than 15%. While the results to date are preliminary and indicative innature, it would appear that there is a vertical stratification in the acidity of sulfate-containingaerosols in the troposphere. DOI: 10.1111/j.1600-0889.1983.tb00024.x