Remote sensing measurements for evaluation of air quality in an urban area.

The Differential Optical Absorption Spectrometry (DOAS) is a remote-sensing technique finding greater consents in these last years. The analytical principle of the DOAS system is based on the light absorption in the near-UV and Vis regions of those pollutants with fine vibrational structures such as SO2, NO2, O3, nitrous acid, formaldehyde, benzene, toluene, etc.. The relationship among the adsorbed light intensity and the xompound concentrations is ruled by the Lambert-Beer's law. The DOAS analysis allows to study and to interpretate the complex mechanisms of the formation and transformation of the pollutants and particularly of those of secondary origin. In this paper we have reported and discussed the behaviors of NO2, O3, HNO2, formaldehyde, benzene and toluene measured by this system during the 2000--2003 period in the Rome area (an area highly influenced by anthropogenic sources) and in Pietracupa (Molise) area (considered as remote site). The results show how the DOAS system highlight very well the secondary pollution evolution; this, described by the profiles of NO2 and O3 being at the same time products and precursors of the photochemical smog, is not influenced by the emission flow intensity and consequently assumes homogeneous values in the whole urban area.

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).

The atmospheric monitoring in a protected area.

A multi-annual research program was carried out to study the environmental quality of Castelporziano Presidential Estate (Rome, Italy). Within this program, in the field of air quality, a methodological approach was defined and applied, even by means of proper Environmental Indicators for the identification of anthropogenic contribution and the quantification of degradation. By means of mobile laboratories, macro and micro-pollutant concentrations were assessed in order to define Indexes of Atmosphere Quality and Diffuse Contamination, by relating them to possible short or long-range emission sources. Wet and dry atmospheric depositions were collected and analysed for the determination of heavy metal and acid species fluxes. Critical Load and relative Exceedance maps were elaborated, for the purpose of better underline the areas characterized by a higher environmental vulnerability.

[Organic and elemental carbon in atmospheric particles]. / Carbonio organico e carbonio elementare nelle particelle atmosferiche.

The carbonaceous material, present especially in the respirable atmospheric particulate, is emitted directly from the combustion processes and it is composed of an organic fraction, organic carbon (OC) and of a fraction which is resistant to oxidation at temperatures below approximately 400 degrees C, elemental carbon (EC). In this paper OC and EC concentrations are reported measured in downtown Rome and in a park, Villa Ada, by means of an analyzer which utilizes the thermal properties of the particles. The temporal trends of EC and OC in Rome are in good agreement during the entire period investigated (correlation coefficient between 0.86-0.90). On the other hand the comparison with Villa Ada shows a different contribution from secondary origin pollutants. The carbonaceous fraction in the total particulate mass, measured by means of a TEOM analyzer, varies between 30-40% in downtown and 20-25% in the park, respectively.

Carbonaceous components in atmospheric aerosol: measurement procedures and characterization.

Carbonaceous material in the particulate matter was measured in Rome urban area. The carbonaceous material constitutes a significant component of total aerosol mass (30-40%) and it is composed by two main fractions, elemental carbon (EC) and organic carbon (OC). EC is essentially a primary pollutant emitted directly from incomplete combustion processes whereas OC has both primary and secondary origin. A chemical OC investigation has been carried out in order to determine the nalkanes, the n-alkanoic acids, the polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs by means an HRGC-MS procedure. A different seasonal distribution of these compound classes attributed to photochemical radical activity (n-alkanes and PAH decrease in spring- and summertime) and to biogenic plant emission (n-alkanoic acid increase in summertime) has been evidenced.