Origin of anthropogenic hydrocarbons and halocarbons measured in the summertime European outflow (on Crete in 2001)
1Max Planck Institut for Chemistry, Air Chemistry Department, P.O. Box 3060, 55020 Mainz, Germany
2Institute for Marine and Atmospheric Research Utrecht (IMAU), Utrecht University, The Netherlands
3Deutscher Wetterdienst, Hohenpeissenberg, Germany
4Teledyne-API, 6565 Nancy Ridge Drive, San Diego, CA 92121, USA
5National Center for Atmospheric Research, Boulder, Colorado, USA
Abstract. During the Mediterranean Intensive Oxidant Study MINOS in August 2001, 87 air samples were collected at the ground-based station Finokalia (35° 19' N, 25° 40' E) on the north coast of Crete and subsequently analysed by GC-MS. The analysis includes various hydrocarbons, organo-halogens, HCFCs and CFCs. These compounds have a wide variety of sources and sinks and a large range of atmospheric lifetimes. By plotting the measured variability of these species against lifetime, we found that the compounds describe a linear relationship. It is shown, based on air mass origin analysis and chemical ratios, that several distinct anthropogenic sources influenced the atmospheric composition in Crete. Propane observations are compared to a global model to assess the fossil fuel related emission inventory. Although the model reproduces the general pattern of the propane variations, the model mixing ratios are systematically too low by a factor of 1.5 to 3, probably due to an underestimation of the propane emissions from east European countries in the underlying global database EDGAR. Another important finding was that methyl chloroform, a compound banned under the Montreal protocol, showed significant enhancements from background, which were well correlated with CFC-113. This suggests continued use and emission of methyl chloroform by one or more European countries. We also discuss the observed variations of bromomethane and suggest that the significant peak observed on 12 August 2001 reflects heavy agricultural use as a soil fumigant in Italy.