Relating Saharan Dust to Particulate Matter Amounts in the City of Rome (Italy), a Four-Year Study

A record of Saharan dust advection events for the period 2001-2004 is cross- correlated to concentration of PM10, PM2.5, and ultra fine particles measured at a multi- parameter monitoring station in the city of Rome (Italy) to infer the impact of these natural conditions on the local air quality. Saharan events are either detected by lidar (laser radar) observations carried out at CNR-ISAC Rome or forecasted by operational models. Particle observations are carried out at the ISS Rome, heavy traffic site, together with CO measurements employed to provide a proxy for combustion sources of particles. Meteorological data are exploited to evaluate the relevant modulation on particulate matter levels. Saharan advection over Rome occurred on ~27% of the time. The analysis shows that Saharan dust events have a meaningful impact on the PM10 (but also on PM2.5) levels observed in the city. However, combustion-related, meteorological and Saharan sources of PM explain less than 50% of the PM10 and PM2.5 variance