Compositional and morphological characterization of urban particulate matter sampled with passive method in the Ferrara area (North-East Italy).

In the last decades atmospheric particulate materials have been widely studied, most of them with chemical scope (Bernabe´ et al., 2003; Bogo et al., 2003). Atmospheric aerosols are today a key issue in air pollution, mostly related to public health. In particular as far as urban aerosols concerns, the characterization in size and composition of their variety is difficult, due to lack of routine analytical techniques. This subsequently led to an insufficient epidemiological dataset on the effect of various components on human health. Today's legislation is limited to specify a certain mass of particles per cubic centimeter (Blacque Belair et al., 1991), irrespective of their size and composition. This is particularly unsatisfactory since smaller particles 1 m are believed to be more relevant to public health than bigger ones (Blacque Belair et al., 1991), and that certain types of aerosols are more chemically active than others (Imre and Xu, 1997). It is difficult to achieve spatial distribution of the aerosols, because in situ sampling techniques only provide spot measurements at the ground level. Two test areas in the medium industrial city of Ferrara were studied using SEM technique to identify the environmental impact of some potential pollutant sources. Samples were collected in June 2006 and the data compared with previous analyses (Besco et al., 2006). This was to verify if the difference in the particulate matter composition can be related to seasonal variation. Collection was by adhesive tapes applied on the surface of road signs, and situated at the same height in horizontal position. This non-conventional type of collection has been preferred because it allows to select the particulate matter, moving on air with diffusion movement, and to exclude the particles usually deposed following gravity rules. Dimensional characterization has shown that usually the smaller particles tend to aggregate themselves in bigger polycrystalline particles with geometric diameter of up to 10 m. The wide variety in the morphology of the particulate matter sampled made difficult to define a morphological classification of them. Particles derived from oil combustion have been clearly recognized by their cenospheric morphology. Pollens show rounded forms with microstructures covering the surface. As for micro-analytical data, despite that the particulate matter in this study has revealed a wide heterogeneous range of compositions, it has been possible to distinguish the follow particles' groups: more abundant with silicate and mixed (Si+C), with carbonate, with chlorine, with sulphate, with carbon, and organic (subordinate). This preliminary study has highlighted that Ferrara is affected by an environmental problem linked to the presence of particulate matter induced by industrial activities as some of the most polluted cities in the world. The observations and the analytical data have pointed out the need for further investigation to better define the features of the fine particulate matter. This will be useful not only to prevent human disease, but also to preserve the cultural heritage of this Medieval-Renaissance city. References: Bernabé J.M., Carretero, M.I., García Orellana, I., 2003. Abstracts Book of Air Pollution and Cultural Heritage. Seville, Spain, pp. 65-66. Bernabé, J.M., Carretero, M.I., 2003. Boletín de la Sociedad Espanõla de Mineralogía 26, 167-177. Besco L:, Caniatti F., Marrocchino E., Vaccaro C. 2006. Atti del XXII Congresso Nazionale della Società Chimica Italiana, Firenze. Blacque Belair, A., De Fossey, B. M. and Fourestier, N. 1991. 6th Edn. Maloine. Bogo, H., Otero, M., Castro, P., Ozafrán, M.J., Kreiner, A., Calvo, E.J., Martín Negri, R., 2003. Atmospheric Environment 37, 1135-1147. Imre, D. and Xu, J. 1997. Geophysical Research Letters 24, 69-72.