0000000000049555
AUTHOR
Harald Stark
Estimating the contribution of organic acids to northern hemispheric continental organic aerosol
Using chemical ionization mass spectrometry to detect particle-phase acids (acid-CIMS) and aerosol mass spectrometry (AMS) measurements from Colorado, USA, and two studies in Hyytiala, Finland, we quantify the fraction of organic aerosol (OA) mass that is composed of molecules with acid functional groups (facid). Molecules containing one or more carboxylic acid functionality contributed approximately 29% (45-51%) of the OA mass in Colorado (Finland). Organic acid mass concentration correlates well with AMS m/z 44 (primarily CO2+), a commonly used marker for highly oxidized aerosol. Using the average empirical relationship between AMS m/z 44 and organic acids in these three studies, together…
A new method to retrieve the aerosol layer absorption coefficient from airborne flux density and actinic radiation measurements
A new method is presented to derive the mean value of the spectral absorption coefficient of an aerosol layer from combined airborne measurements of spectral net irradiance and actinic flux density. While the method is based on a theoretical relationship of radiative transfer theory, it is applied to atmospheric radiation measurements for the first time. The data have been collected with the Spectral Modular Airborne Radiation Measurement System (SMARTA¢ÂÂAlbedometer), the Solar Spectral Flux Radiometer (SSFR), and the Actinic Flux Spectroradiometer (AFSR) during four field campaigns between 2002 and 2008 (the Saharan Mineral Dust Experiment (SAMUM), the Influence of Clouds on the Spectra…