Shrinkage of Newly Formed Particles in an Urban Environment

摘要: New particle formation (NPF) significantly influences the number concentrations and size distributions of an atmospheric aerosol is often followed by rapid growth newly formed particles. Recently a reversal process leading to shrinkage was reported found occur under specific conditions, which are unfavourable for nucleated In this study we present analysis events following prior NPF at urban background station in Prague, Czech Republic. The based on two-year measurements using Scanning Mobility Particle Size (SMPS). A total 22 were identified vast majority observed spring summer seasons. determined rates span range from -2.5 -12.5nm/h. During most intensive events, grown particles shrank back smallest measurable 10nm. attributed evaporation previously condensed volatile semi-volatile species particulate phase gas phase. When analysing dependence meteorological peak global radiance intensity, gradually decreasing, or sharp drop intensity. also related high ambient temperature low relative humidity. occurrence mixing promote very effectively, because decrease vapour concentration due changing conditions more than caused lower photochemical activity solar radiation