A procedure for the evaluation of the historical trend of atmospheric pollution in an urban area

Air pollution in large urban areas is still a sanitary emergency even though significant improvements have been reached in fuel quality and vehicular emissions. Many air pollutants when inhaled are toxic to humans and can cause threats to the respiratory system and chest congestion and other health problems. The correlation between concentration of atmospheric pollutants and health impact is not straightforward due to the complexity of atmospheric mixtures and antagonistic or synergic effects of pollutants. At the same time public authorities needs tools for the evaluation of their policies for the mitigation of air pollution. A possible approach to both these problems is the evaluation of historical trends of air pollution in urban areas to be compared with sanitary data or for the evaluation of the effectiveness of environmental policies. In this paper a procedure to evaluate historical trends of air pollution has been developed using air pollution indexes. Data collected by the air monitoring quality network in the urban area of Naples from 2001 to 2007 have been analysed to evaluate three different daily air quality indexes. The different indexes were compared to check the correlation among them. Some correlation exists among the indexes considered but distribution in defined risk classes was different. Therefore, the three indexes considered can not be assumed as equivalent. Only correlation with sanitary data can help to select which index is the most apt. A statistical analysis was then developed to obtain an historical trend of air pollution in Naples. Even though with some differences, all indexes show that from 2001 to 2007 the air quality in Naples is, on the average, improved.