Long period benzene measurements in urban atmosphere

Periodogram analysis has been used as an interpretative tool of long period measurements of benzene concentration in urban atmosphere. By removing the request of evenly sampled data, the periodogram allows to extend spectral analysis to this kind of data, which usually suffer the "missing data" prob lem due to instrument vacancies. In this way it is possible to identify the periodic behaviour of data concentration and then reproduce it by means of harmonic functions even for very incomplete experimental information allow ing a good evaluation of some important statistical properties of data.