Significant Spatial Gradients in New Particle Formation Frequency in Greece during Summer
ANDREAS AKTYPIS, David Patoulias, Christos Kaltsonoudis, Angeliki Matrali, Christina Vasilakopoulou, Nikolaos Mihalopoulos, Panagiotis Kalkavouras, Aikaterini Bougiatioti, Nikos Kalivitis, Konstantinos Eleftheriadis, Stergios Vratolis, Maria Gini, Athanassios Kouras, Mihalis Lazaridis, Sofia-Eirini Chatoutsidou, Athanasios Nenes, Spyros Pandis,
University of Patras, Greece Abstract Number: 281
Working Group: Aerosols, Clouds and Climate
AbstractHomogeneous nucleation is an important source of new particles in the atmosphere. The resulting newly formed stable nuclei can grow to larger sizes and affect air and climate. Unexpected significant spatial variability of the nucleation frequency has been observed in Greece in the only previous study; high frequency in Thessaloniki, intermediate in Eastern Crete and low in Patras (Patoulias et al., 2018). Our hypothesis is that Greece may be an excellent natural laboratory to investigate the factors affecting nucleation and to understand the reasons behind this surprising variability.
Extensive continuous aerosol size distribution measurements took place during two summers (2020 and 2021) in the frame of the PANACEA project in 11 different locations all over Greece. The instrumentation used included several scanning mobility particle sizers (SMPS) and a suite of gas (SO
2, NOx, NH
3 and CO) monitors. A particle size magnifier (PSM) was deployed in Patras during the 2021 campaign providing valuable information regarding nanoparticles with diameter down to 1 nm.
The observations suggest that indeed the nucleation frequency during summer in Greece varies from close to zero in the southwestern part of the country to more than 80% in the northern central and eastern regions. The detailed analysis of the measurements in Patras suggests that nucleation was infrequent in this location, but particles that were formed a few hours earlier over central Greece are often transported to this area after they have grown to sizes of 20-30 nm. Analysis of the backward air trajectories arriving in Patras was performed to locate the areas in which new particles are formed. The corresponding measurements in Patras were also used to estimate the corresponding particle growth rates. The analysis of the measurements in the various sites shows that the proximity to coal-fired power plants is a major factor affecting the nucleation frequency.