Sub-micron atmospheric aerosols in the surroundings of Marseille and Athens: physical characterization and new particle formation

摘要

The properties of atmospheric aerosol particles in Marseille and Athenswere investigated. The studies were performed in Marseille, France,during July 2002 and in Athens, Greece, during June 2003. The aerosolsize distribution and the formation and growth rates of newly formedparticles were characterized using Differential Mobility ParticleSizers. Hygroscopic properties were observed using a Hygroscopic TandemDifferential Mobility Analyzer setup. During both campaigns, theobservations were performed at suburban, almost rural sites, and thesites can be considered to show general regional background behaviordepending on the wind direction. At both sites there were clear patternfor both aerosol number concentration and hygroscopic properties.Nucleation mode number concentration increased during the morning hoursindicating new particle formation, which was observed during more than30% of the days. The observed formation rate was typically more than1 cm−3 s−1, and the growth rate was between1.2–9.9 nm h−1. Based on hygroscopicity measurements in Athens,the nucleation mode size increase was due to condensation of both waterinsoluble and water soluble material. However, during a period of lessanthropogenic influence, the growth was to a larger extent due to waterinsoluble components. When urban pollution was more pronounced, growthdue to condensation of water soluble material dominated.