The evolution of sulfur oxides and suspended particles (smoke and settleable materials) in the atmosphere of the Spanish Mediterranean city of Valencia, corresponding to the period 1979-1989, were determined. The contamination levels in industrial versus residential areas of the city were contrasted, as were the relative contributions of each zone to the mean total of each contaminant. Also determined were the mean annual concentrations of each contaminant in order to investigate long-term risks and the 98 percentile value in the case of short-term risk. Finally, a simple regression analysis was performed to find the inter-associations of these atmospheric contaminants and their relation to traffic density in each area. A decrease was observed in the emission levels of sulfur oxides and settleable materials in this period. On the other hand, the smoke levels were found to increase. A positive correlation was found between sulfur oxide concentration and traffic density. Likewise, no effectively reliable association was seen between smoke and traffic density.

A retrospective study of 143 patients histologically diagnosed with non-melanoma skin cancer (NMSC) was carried out in order to evaluate the influence of ultraviolet (UV) radiation on the appearance of more than one NMSC in the same person. Descriptive statistical and logistic regression analyses were carried out for each variable and its possible interaction, in order to determine the potential appearance of multiple NMSC. The results obtained were in agreement with those of earlier studies. A significant relationship was observed between occupational UV exposure and individuals with more than one NMSC. Those patients tended to be blue-eyed and were chronically exposed to UV radiation as a result of occupational activities (although not always in leisure activities); most did not take protective measures such as the use of hats or creams.