Guglielmo A., Carati G., Carlini E., Marzi C., Donati D.

The Italian policy concerning the environmental noise measurement and management, pursuant to the Framework Law on noise pollution. No.447 of 1995 and Its concerning decrees, sets the LAeq value (A-weighted equivalent continuous sound pressure level) as indicator for environmental noise evaluation. In particular, the Italian decree DPCM (Decree of the President of the Republic) No.280 of 14.11.1997 sets daytime and night-time noise emission limits (limits set at the source of noise) and immission limits (set at the receiver), for each type of land use, in accordance with law n° 447/95. According to the Legislative Decree No.194 of 19.08.2005, the appropriated environmental descriptor for noise pollution determination and management will be in a near future the day-evening-night level (Lden), calculation based on noise levels measured in these three different reference periods: (day - evening - night). The present paper outlines the methodology for converting the equivalent continuous sound level into the new European indicator Lden, from numerous long-term sound level measurements carried out within the administrative area of Rome's municipality. The main objective of this paper is to develop a chart, which reading makes possible to identify the values of the 'new' noise levels values (Lden, Lday, Lnight and Levening) from 'old' (day and night) noise levels (LAeqD, LAeqN) and from statistical distribution of levels measured on such periods. Subsequently, the analysis has been extended to the determination of limit values afferent to each type of land use