摘要：Summary. The main objective of this study was to asses the temporal variation (1999 trough 2008)
of air quality in Rome, focusing on airborn concentration of selected pollutants (PM10 and PM2.5
mass concentration and particle number concentration, PNC, carbon monoxide, CO, nitrogen
oxides, NO and NO2) used for health effects assessment in epidemiological analyses. Time series
analysis using Seasonal Kendall test has been applied. A statistically significant decreasing trend
was found for primary gaseous pollutants and total particle number concentrations. Moreover a
decreasing trend was assessed for PM10, PM2.5 and NO2 measured at traffic oriented sites even if the
estimated reduction was lower compared with NO, CO and PNC. The urban background PM10 and
NO2 concentrations seem to be practically unchanged since 1999 as no statistically significant trends
were found. All the pollutants show higher slope of the estimated trend line at traffic oriented sites
compared with those observed at the urban background. Thus a reduction of the intra-city concentration
variability throughout the years occurred
关键词：Key words: trends, particulate matter, air pollution
