NORTHERN FOEHN AND GROUND-LEVEL OZONE AT ISPRA

High ozone concentrations in tropospheric air are usually related to photochemical processes caused by anthropogenic emission on local or regional scales. In the prealpine region, comparable levels may be reached during foehn events as a result of injections of air masses from the free troposphere. From the analysis of meteorological parameters of the foehn episodes which occurred in 1988 at Ispra and the corresponding ozone levels recorded at the nearby EMEP station, a classification of different events has been attempted. In particular, a correlation between wind speed and ozone level is demonstrated. © 1990 Società Italiana di Fisica.