Technical details on the apparatus and the CO2 program at Mt. Cimone are reported, together with information on the sampling site and on the regime. Hourly values of atmospheric CO2 are examined, and a preliminary interpretation is given, taking into account simultaneous observations of wind direction and wind speed at Mt. Cimone. In particular, a seasonal CO2 trend is clearly identified along with a CO2 dependence on synoptic situations, especially wind speed and direction.