A preliminary evaluation of unexpected ozone levels measured in Falconara, Italy

Ozone is a secondary pollutant that forms in the atmosphere through complex chemical reactions mainly between Nitrogen Oxides ( NOx ) and Volatile Organic Compounds (VOC ); such reactions are triggered by the presence of solar radiation. In this paper the Ozone formation in Falconara area, an industrialized area located on the central Adriatic coast of Italy, has been examined during a period of high ozone concentrations that occurred on August 2000 to understand spike phenomena registered in some ozone time series. The selected data set consists of concentration hourly averages and related elementary values, both provided by the monitoring network of Ancona Province, Italy. We have analysed hourly averages to investigate long-term and medium-term behaviour of pollutants, while elementary values have been used to study scattering phenomena (low frequency and high frequency fluctuations in concentration levels) registered in some ozone time series. Spectral analysis has been performed over air pollutant time series; the focus has been set on photochemical pollutants traced by ozone concentrations, considering potential correlations with chemical precursors, and atmospheric parameters such as solar radiation, wind velocity and air temperature. Analyses conducted led to the hypothesis that the processes that generate ozone in Falconara are more rapid and efficient than in other urban areas, and that ozone production varies significantly over shorter spatial scales than in other urban areas. Results have yielded to possible explanations regarding the origins of oscillations.