open6We introduce a new instrument for sampling the airborne particulate matter (PM) while
monitoring the black carbon (BC) atmospheric concentration. The concentration of PM and BC are
usually measured by separate instruments with possible systematics differences even in the collecting
inlets. The new equipment is based on a low-volume sequential PM sampler, fully compliant
with the EU-CEN and US-EPA regulatory standards, with a built-in optical BC monitor. The BC
concentration is continuously measured during the sampling in the PM accumulated on the filter
while the PM concentration can be obtained off-line by a standard gravimetric analysis. The optical
set-up, upstream the collecting filter, is composed by a single wavelength light source (λ = 635 nm)
and a photodiode, placed in way to receive the light backscattered by the filter surface at a fixed angle.
The mechanical arrangement does not introduce any perturbation to the PM sampling. Thanks to an
original calibration curve, the sample absorbance is deduced from the output signal of the photodiode.
Finally, the BC concentration is obtained through the Mass Absorption Coefficient (MAC). After the
sampling and the PM gravimetric determination, the same filter can be sent to other compositional
analyses. Thermo-optical quantification of the Elemental and Organic Carbon (EC and OC) in the
filter sample can thus be exploited to tune the MAC value to the PM composition of a particular site.
The main features of the new instrument and the set of validation tests against other PM samplers
and BC monitors of widespread use (i.e.,: Multi Angle Absorption Photometer and aethalometer) are
detailed and discussedopenLorenzo Caponi,Gianluca Cazzuli,Giulio Gargioni,Dario Massabò,Paolo Brotto, Paolo PratiCaponi, Lorenzo; Cazzuli, Gianluca; Gargioni, Giulio; Massabo', Dario; Brotto, Paolo; Prati, Paol
