New particle formation and ultrafine charged aerosol climatology at a high altitude site in the Alps (Jungfraujoch, 3580 m a.s.l., Switzerland)

Abstract

Aerosol nucleation is an important source of atmospheric particles which have an effect both on the climatic system and on human health. The new particle formation (NPF) process is an ubiquitous phenomenon, yet poorly understood despite the many studies performed on this topic using various approaches (observation, experimentation in smog chambers and modeling). In this work, we investigate the formation of secondary charged aerosols and its climatology at Jungfraujoch, a high altitude site in Swiss Alps (3580 m a.s.l.). Charged particles and clusters (0.5–1.8 nm) were measured within the EUCAARI program from April 2008 to April 2009 and allowed the detection of nucleation events. We found that the aerosol concentration, which is dominated by cluster size class, shows a strong diurnal pattern and that the aerosol size distribution and concentration are strongly influenced by the presence of clouds either during daytime or nighttime conditions. New particle formation events have been investigated and it appears that new particle formation occurs 17.5% of measured days and that the nucleation frequency is strongly linked to air mass origin and path and negatively influenced by cloud presence. In fact, we show that NPF events depend on the occurrence of high concentration VOCs air masses which allowed clusters growing by condensation of organic vapors rather than nucleation of new clusters. Furthermore, the contribution of ions to nucleation process was studied and we found that ion-mediated nucleation (IMN) contribute to 26% of the total nucleation so that ions play an important role in the new particle formation and growth at Jungfraujoch

A long-term study of new particle formation in a coastal environment: Meteorology, gas phase and solar radiation implications

“…This could indicate that under sea-land breeze patterns, a simultaneous accumulation of particles (within the accumulation size fraction) and gas, creates condensing vapour that is most likely coupled with high CS values. Similar behaviour has also been observed at Jungfraujoch station (Boulon et al, 2010). If the atmospheric recirculation is not observed, as during Class NB events, there is not an accumulation of particles and gas and the correlation between GR 14-30 and CS is not observed.…”

Atmospheric ions and new particle formation events at a tropical location, Pune, India

“…The depression between these two maxima can be associated with the time interval between occurrence of PECIA and NPF events. The peak at 0100 and the depression between 0200 and 0400 LT are most likely to be associated with variability in the nocturnal process of particle formation and growth (Lee et al , ; Boulon et al , ; Ortega et al , ; Kecorius et al , ). It is notable in Figure that enhancement in values of N / N ± corresponds to relatively bigger ions and particles (∼16–25 nm) during PECIA and smaller ions and particles (∼4.6–12 nm) during the NPF period.…”

“…Recently, NPF events have been reported to occur at night‐time and at high altitude sites (Venzac et al , ; Lee et al , ; Boulon et al , ; Ortega et al , ; Gonser et al , ; Kecorius et al , ). It has been reported that transportation of air masses in valleys and the variations in radon concentration and the ionization produced by it can influence the formation and growth of new particles.…”

Different characteristics of new particle formation between urban and deciduous forest sites in Northern Japan during the summers of 2010–2011

“…NPF also has been observed at remote high elevation sites (Nishita et al, 2008;Venzac et al, 2008;Boulon et al, 2010Boulon et al, , 2011Hallar et al, 2011). Nucleation frequency varied depending on geographical locations: 17 % of measurement days at Mount Norikura (2770 m a.s.l.)…”