Interpretation of atmospheric pollution phenomena in relationship with the vertical atmospheric remixing by means of natural radioactivity measurements (radon) of particulate matter.

In this paper the results of seasonal monitoring campaign for primary (benzene and carbon monoxide) and secondary (nitrogen dioxide and ozone) pollutants and for the natural radioactivity of the particulate matter in the urban area of Rome, are reported to investigate acute atmospheric pollution episodes. Comparing the daily concentration trends of primary and secondary pollutants with those of the natural radioactivity, considered as index of the vertical diffusion in the low boundary layer, it has been evidenced that the acute pollution episodes in Rome occur in the winter period for the high atmospheric stability (primary pollution) and in the summer period for the strong diurnal atmospheric remixing (secondary pollution).

Description of the carbonaceous particulate matter evolution in an urban area.

The ground concentrations of particulate matter, total carbon, elemental carbon and organic carbon were measured in a monitoring station located inner a park in downtown Rome. The description of the evolution of the boundary layer is given by radon concentration measurements. The results show that the particulate matter of Rome contains about 30% of carbonaceous matter. The elemental and organic carbon behaviours show that elemental carbon is essentially a primary pollutant emitted directly from vehicular traffic and organic carbon behaviour instead can be primary (combustion and biogenic emission) and secondary. A chemical fine particulate matter mass balance is given; an organic carbon investigation has been carried out in order to determine n-alkanes, n-alkanoic acids and polycyclic aromatic hydrocarbons.