Members from the APCG group served as authors for a newly published article in Atmospheric research. This is the first time, to our knowledge, that long-term size distribution measurements are analyzed for new particle formation (NPF) events, in a comparative way, between an urban and a regional background site in this region. The study uses concurrent measurements at at the urban background (UB) site of the National Observatory of Athens (NOA) at Thissio, and at the regional background (RB) site of Finokalia in Crete, from August 2015 to August 2016, and from February 2017 to February 2018. The results show that the formation rates during NPF were higher at the urban environment, however lower growth rates were evidenced in comparison to regional background conditions. The concurrent events measured at both sites were associated with air mass trajectories from the Northern sector.