In:
Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 23, No. 3 ( 2023-02-13), p. 2167-2181
Abstract:
Abstract. In this work, new particle formation events (NPFs)
occurring at two locations in southern Italy, the urban background site of
Lecce (ECO station) and the coastal site of Lamezia Terme (LMT station), are
identified and analyzed. The study aims to compare the properties of NPF
events at the two sites, located 225 km away from each other and
characterized by marked differences in terms of emission sources and local
weather dynamics. Continuous measurements of particle number size
distributions, in the size range from 10 to 800 m, were performed at
both sites by a mobility particle size spectrometer (MPSS). The occurrence
of NPF events, observed throughout the study period that lasted 5 years,
produced different results in terms of frequency of occurrence: 25 % of
the days at ECO and 9 % at LMT. NPF events showed seasonal patterns:
higher frequency during spring and summer at the urban background site and the autumn–winter period at the coastal site. Some of these
events happened simultaneously at both sites, indicating the occurrence of
the nucleation process on a large spatial scale. Cluster analysis of 72 h
back trajectories showed that during the NPF events the two stations were
influenced by similar air masses, most of which originated from the
north-western direction. Local meteorological conditions characterized by
high pressure, with a prevalence of clear skies, low levels of relative
humidity (RH 〈 52 %), and moderate winds (3–4 m s−1)
dominated the NPF events at both sites. Notable differences were observed in
SO2 and PM2.5 concentrations and H2SO4 proxy levels,
resulting in ∼65 %, ∼80 %, and 50 %
lower levels at LMT compared to ECO, respectively. It is likely that the lower
level of that which is recognized as one of the main gas precursors involved in the
nucleation process could be responsible for the smaller NPF frequency of
occurrence (∼60 % less than ECO) observed in LMT.
Type of Medium:
Online Resource
ISSN:
1680-7324
DOI:
10.5194/acp-23-2167-2023
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2023
detail.hit.zdb_id:
2069847-1
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