Size distributions of ambient organic and elemental carbon

A microorifice uniform deposit impactor (MOUDI) was used to measure size distributions of organic and elemental carbon in ambient aerosols in remote and polluted atmospheres. The most striking observation resulting from these measurements was the consistently large proportion of the organic carbon (40%-70%) on the Pallflex quartz (QAO and QAST) afterfilters. A variety of possible explanations for the high organic carbon loadings on the quartz afterfilters is discussed. It is concluded that these high afterfilter loadings are attributable, at least in part, to the adsorption of carbon-containing vapors on the quartz afterfilters.