ACPD Atmospheric Chemistry and Physics Discussions ACPD 1680-7375 Copernicus GmbH Göttingen, Germany 10.5194/acpd-2-1509-2002 Ozone production and trace gas correlations during the June 2000 MINATROC intensive measurement campaign at Mt. Cimone Fischer H. 1 Kormann R. 1 Klüpfel T. 1 Gurk Ch. 1 Königstedt R. 1 Parchatka U. 1 Mühle J. 1 Rhee T. S. 1 Brenninkmeijer C. A. M. 1 Bonasoni P. 2 Stohl A. 3 Max Planck Institute for Chemistry, POB 3060, 55020 Mainz, Germany National Research Council, Institue of Atmospheric Sciences and Climate, via Gobetti 101, 40129 Bologna, Italy Technical University of Munich, Chair of Bioclimatology and Air Pollution Research, Am Hochanger 13, 85354 Freising-Weihenstephan, Germany 07 10 2002 2 5 1509 1543 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys-discuss.net/2/1509/2002/acpd-2-1509-2002.html The full text article is available as a PDF file from http://www.atmos-chem-phys-discuss.net/2/1509/2002/acpd-2-1509-2002.pdf

An intensive measurement campaign was performed in June 2000 at the Mt. Cimone station (44°11' N -- 10°42' E, 2165 m asl, the highest mountain in the northern Italian Apennines) to study photochemical ozone production in the lower free troposphere. In general, average mixing ratios of important trace gases were not very high (121 ± 20 ppbv CO, 0.284 ± 0.220 ppbv NO<sub>x</sub>, 1.15 ± 0.8 ppbv NO<sub>y</sub>, 58 ± 9 ppbv O<sub>3</sub>), which indicates a small contribution by local pollution. This is supported by the analysis of volatile organic compounds (VOCs), that exhibit mean levels typical for background continental air (e.g. 905 ± 200\,pptv C<sub>2</sub>H<sub>6</sub> 268 ± 110\,pptv C<sub>3</sub>H<sub>8</sub>, 201 ±102 pptv C<sub>2</sub>H<sub>2,</sub> 111 ± 124 pptv isoprene, 65 ± 33 pptv benzene). Furthermore, significant diurnal variations for a number of trace gases (O<sub>3</sub>, CO, NO<sub>x</sub>, NO<sub>y</sub>, HCHO) indicate the presence of free tropospheric airmasses at nighttime as a consequence of local catabatic winds. Average mid-day peroxy radical concentrations at Mt. Cimone are of the order of 30 pptv. At mean NO concentrations of the order of 40 pptv this gives rise to significant in situ net O<sub>3</sub> production of 0.1--0.3 ppbv/hr. The importance of O<sub>3</sub> production is supported by correlations between O<sub>3</sub>, CO, NO<sub>z</sub>, and HCHO, and between HCHO, CO and NO<sub>y</sub>.