Montelupo Fiorentino is a little town about 20 km west of Florence, characterised by the presence of

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Particulate matter composition in an industrial
district near to Florence Massimo Chiaria, Piero
Del Carminea, Franco Lucarellia, Graziella
Marcazzanb, Silvia Navac,Leonardo Paperettia,
Paolo Pratic, Gianluigi Vallib, Roberta Vecchib,
Alessandro Zucchiattic a Physic Dept. and INFN -
Firenze, b Istituto di Fisica Generale Applicata
- Milano, c Physic Dept. and INFN - Genova
Introduction Montelupo Fiorentino is a little
town about 20 km west of Florence, characterised
by the presence of a large number of ceramic and
glass factories. Since the PM10 mean value in the
area is higher than the new Air Quality Directive
(1999/39/EC) recommended value and potentially
harmful elements can be emitted by the local
industrial activities, we decided to start a
deep investigation to determine the mass
concentrations and the elemental composition of
the PM10, PM2.5 and PM1 fractions of the aerosol.
Sampling PM10, PM2.5 and PM1 samples were
collected, on a daily basis, on 47 mm diameter
Teflon filters, by three single-mode sequential
samplers (one PARTISOL 2025 and twoIND PNS15D),
located 4 m above ground level, on the roof of an
air quality monitoring station. Mass
concentrations were obtained using an analytical
balance. The sampling campaign lasted from the
24th of September 2002 to the 2nd of July 2003
during certain periods we mounted the same inlet
on all the instruments to carry on a systematic
comparison between the three devices (about ten
days for each fraction) during 3 weeks we put a
different inlet on each instrument to measure the
granulometric fraction ratios (i.e. PM2.5/PM10
and PM1/PM10). Starting from the 21st of December
we continued the sampling with only one IND
sampler with PM10 inlet.
Ion Beam Analysis at the Van de Graaff
accelerator in Florence The concentrations of
the elements with Z gt 10 were measured by
Particle Induced X-ray Emission (PIXE) at the
external beam facility. PIXE measurements were
performed at2.2 MeV proton energy to reduce the
Compton g-ray background produced by the fluorine
in the Teflon filters. The X-ray spectra have
been fitted for 28 elements (Na, Mg, Al, Si, P,
S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn,
As, Se, Br, Sr, Zr, Pb, Mo, Cd, Sb, Sn) using the
GUPIX software package. To obtain a complete
reconstruction of the aerosol mass, we
implemented the detection of H, C, N and O by
in-vacuum Particle Elastic Scattering Analysis
(PESA). Assuming a constant C/F ratio in Teflon,
the contribution due to the carbon content of the
filter to be subtracted to the total C signal is
proportional to the local filter thickness and
to its F content, which can be measured by
Particle Induced g-ray Emission (PIGE) analysis
(simultaneously with PESA) exploiting the
19F(p,pg)19F reaction (Eg 110 keV).
Quantitative results were obtained by direct
comparison with thin standards (supplied by
Micromatter Inc.) for PIXE and with a thin
Upilex-S foil (H10C22N2O4) for PESA. Typical
MDLs were 0.1 mg/m3 for H, 1 mg/m3 for C, 0.5
mg/m3 for both N and O, and1-10 ng/m3 for all
the other elements. The absolute concentration of
all the elements could be measured with an error
ranging from 5 to 30 with the bigger errors
affecting concentration values approaching MDLs.
PIXE SET-UP
PESA SET-UP
surface-barrier detectorsq 150 ? C, N, O q
30 ? H
HPGe detector
Si(Li) detectors
aerosol sample
Faraday cup
aerosol sample
Faraday cup
proton beam 2.2 MeV, 10 nA (3 mC per sample)
proton beam 3 MeV, 5 nA (3 mC per sample )
Results The comparison between the three
samplers showed generally a very good agreement
both for mass and for elemental concentrations.
As regards the results from the analysis of
the samples collected simultaneously in the three
fractions, PM2.5 and PM1 turned out to be a
substantial part of PM10 excluding four days in
which there was an anomalous increase in PM10
concentrations respect to PM2.5 and PM1 (Saharan
dust episode), the PM2.5/PM10 and PM1/PM10 ratios
are(0.63 0.09) and (0.46 0.08)
respectively. Al, Si, Ca, Fe, Sr and other
typical crustal elements, and also Zr (produced
by the manufacturing of tiles), are more
concentrated in the PM2.510 fraction, while
elements like H, C, N, O, S, K, Zn, As (mean
concentration 50 ng/m3, with peaks up to 100
ng/m3, related to emissions from artistic glass
manufactures), and Pb are mainly present in the
PM2.5 and PM1 fractions. C, N and O are the
main aerosol components, with carbon giving the
most important contribution to the total mass in
all the fractions (about 40 in PM10 and 50 in
PM2.5 and PM1).
PM10, PM2.5 and PM1 mass concentrations during
the simultaneous sampling of the three fractions.
Percentage contributions of the eight most
abundant elements detected by PIXE and PESA to
the total gravimetric mass. Other PIXE is the
sum of the other elements detected by PIXE. The
values are averaged over the 3 weeks of
simultaneous sampling of the three fractions.
Percentage decomposition of the elemental
concentrations in the three granulometric
fractions. The values are averaged over the 3
weeks of simultaneous sampling of the three
fractions.