Comparative Analyses of Urban Air Quality Monitoring Systems: Passive Sampling and Continuous Monitoring Stations

Indicative methods of measurement are an economical and efficient way of preliminarily evaluating urban air quality. In November and December 2012, there was a campaign to measure NO2, C6H6 and O3 around the city of Catania (Italy) using diffusive samplers (Passam model). Placing the samplers at the fixed sampling sites of the city's monitoring network allowed for a comparison of the concentration values measured by continuous samplers (reference method) with those obtained from passive samplers. For the comparison, the time data of the continuous samplers were mediated as a function of the number of hours of diffusive sampler exposure. With the help of meteorological data from the Sicilian Information Agrometeorological Service (SIAS), it was possible to verify and evaluate any uncertainties associated with the passive samples, since the sample amounts are a function of meteorological variables given they are collected by diffusion. Finally, a statistical analysis based on linear regression highlighted a good correlation between the passive samplers and the fixed monitoring stations.