Particulate matter mass concentrations measured in the city of Rome (Italy) in the period 2001–2004 have been cross-analysed with concurrent Saharan dust advection events to infer the impact these natural episodes bear on the standard air quality parameter PM10 observed at two city stations and at one regional background station. Natural events such as Saharan dust advections are associated with a definite health risk. At the same time, the Directive 2008/50/EC allows subtraction of PM exceedances caused by natural contributions from statistics used to determine air quality of EU sites. In this respect, it is important to detect and characterise such advections by means of reliable, operational techniques. To assess the PM10 increase we used both the “regionalbackground method” suggested by EC Guidelines and a “local background” method, demonstrated to be most suited to this central Mediterranean region. In terms of exceedances, the two approaches provided results within 20% of each other at background sites, and at 50% of each other in traffic conditions.