Behavior of Primary and Secondary Pollutants in Ambient Air of Rome

The hydrocarbons are a significant component in urban air because of combustion, solvent and fuel evaporation and tank leakage and most of aromatic compounds are considered as toxic air contaminants (e.g. benzene) or potential toxic air contaminants (e.g. toluene, xylenes). The no-methane hydrocarbons are considered as precursors for ozone production at the ground level when the sunlight and nitrogen oxides are present. This ozone is usually considered as “bad ozone” which can seriously damage our environment and human health. In fact, no-methane hydrocarbons and aromatic hydrocarbons participate in the formation of urban and suburban photochemical smog with their concentrations influencing greatly the total ozone in different percentage. In this paper, we report the results obtained during ten-years of measurements. The air quality determinations were conducted by automatic analyzers and Differential Optical Absorption Spectrometry investigating traditional atmospheric pollutants like ozone, nitrogen dioxide, nitrous acid, carbon monoxide, formaldehyde, benzene and toluene at the ISPESL Pilot Station located in downtown Rome. The trends of benzene, toluene, CO, NO and IPA are decreased, expecially because of introduction of both the green fuel and the autovehicular catalytic pot. Even if the pollutant levels are decreasing, the sources are still the same and, in particular, the emission from the incomplete combustion of LPG is the most important source of pollution in Rome.