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JOURNAL OF GEOPHYSICAL RESEARCH,
VOL. 107, NO. D22,
8193,
doi:10.1029/2001JD001292,
2002
Urban and rural aerosol characterization of summer smog events during the PIPAPO field campaign in Milan, Italy
U. Baltensperger
Paul Scherrer Institute,
Villigen,
Switzerland
N. Streit
Paul Scherrer Institute,
Villigen,
Switzerland
E. Weingartner
Paul Scherrer Institute,
Villigen,
Switzerland
S. Nyeki
Paul Scherrer Institute,
Villigen,
Switzerland
A. S. H. Prévôt
Paul Scherrer Institute,
Villigen,
Switzerland
R. Van Dingenen
Joint Research Centre,
Environmental Institute,
Ispra,
Italy
A. Virkkula
Joint Research Centre,
Environmental Institute,
Ispra,
Italy
J.-P. Putaud
Joint Research Centre,
Environmental Institute,
Ispra,
Italy
A. Even
ECN,
Netherlands Energy Research Foundation (ECN),
Petten,
Netherlands
H. ten Brink
ECN,
Netherlands Energy Research Foundation (ECN),
Petten,
Netherlands
A. Blatter
Swiss Federal Research Station for Agro-Ecology and Agriculture,
Institute of Environmental Protection and Agriculture,
Bern,
Switzerland
A. Neftel
Swiss Federal Research Station for Agro-Ecology and Agriculture,
Institute of Environmental Protection and Agriculture,
Bern,
Switzerland
H. W. Gäggeler
Paul Scherrer Institute,
Villigen,
Switzerland
Department of Chemistry and Biochemistry,
University of Bern,
Bern,
Switzerland
Abstract
A comprehensive range of aerosol parameters was measured at an urban and a rural site in the Milan, Italy metropolitan region
during summer smog events in summer 1998. Measurements were performed as part of the Pianura Padana Produzione di Ozono (PIPAPO)
field campaign to determine the sensitivity of O3 production to NOX and volatile organic carbon concentrations at several ground stations. Primary aerosol parameters (i.e., direct emissions)
such as aerosol black carbon showed a distinct diurnal variation with maxima at about 0000 and 0800 central European summer
time (CEST), in contrast to secondary aerosol parameters such as sulfate and nitrate. Aerosol number size distributions were
measured under ambient conditions as well as after conditioning with volatility and hygroscopicity systems. A mode at d = 20–30 nm in the number concentration was found at 0800 CEST and exhibited high volatility at 110°C (∼80% volume lost upon
heating) but no hygroscopic behavior. Based on these measurements, small particles (d < 40 nm) are thought to consist mainly of hydrophobic particulate organic matter, rather than soot or H2SO4 aerosols. Two distinct hygroscopic modes with average growth factors d/d0 ∼ 1.02 and 1.21–1.28 were found for particles with dry (relative humidity of <30%) diameters d0 = 50–200 nm. Submicrometer aerosols exhibited lower volatility at the rural than at the urban site, which is attributed to
additional particulate mass produced by secondary particle formation.
Published 24
October
2002.
Index Terms: 0305 Atmospheric Composition and Structure: Aerosols and particles (0345, 4801); 0345 Atmospheric Composition and Structure: Pollution—urban and regional (0305); 0365 Atmospheric Composition and Structure: Troposphere—composition and chemistry; 0322 Atmospheric Composition and Structure: Constituent sources and sinks.
Read Full Article (file size: 558256 bytes) Cited by
Citation: Baltensperger, U., et al.
(2002),
Urban and rural aerosol characterization of summer smog events during the PIPAPO field campaign in Milan, Italy,
J. Geophys. Res.,
107(D22),
8193,
doi:10.1029/2001JD001292.
Copyright 2002 by the American Geophysical Union.
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