Continuous CO and H2 measurements at Mt. Cimone (Italy): Preliminary results

Continuous measurements of atmospheric CO and H2 were carried out in situ at Mt. Cimone, northern Italy (44°12′N, 10°42′E, 2165 m a.s.l.), from May 1994 to date. The preliminary results (1994) are given in this article. Owing to the infrequent exposure to the influence of urban and industrial pollution and in spite of the continental location of the station, low CO and H2 concentrations (means of 164 for CO and of 582 ppbv for H2) were observed over most of the time. Their order of magnitude is comparable to what was found in other similar locations of the northern hemisphere, at similar latitudes. A few examples of different conditions, like pollution from the Po valley (CO increase) or transportation of air masses from the Sahara (CO decrease), are given. CO and H2 concentrations show different types of correlation with other chemical species (CO2, O3, used also as tracers) measured routinely at Mt. Cimone, as well as with meteorological and physical parameters.