2011

@article{Ferrero2011145,
title = {Mixing height determination by tethered balloon-based particle soundings and modeling simulations},
author = {L. Ferrero and A. Riccio and M.G. Perrone and G. Sangiorgi and B.S. Ferrini and E. Bolzacchini},
url = {http://www.sciencedirect.com/science/article/pii/S0169809511002079},
issn = {0169-8095},
year = {2011},
date = {2011-01-01},
journal = {Atmospheric Research},
volume = {102},
number = {1–2},
pages = {145 - 156},
abstract = {Vertical profiles of particle number concentration, potential temperature and relative humidity were measured in the Po Valley using an optical particle counter and a portable meteorological station attached to a tethered balloon. The field campaign covered the period 2006–2008, providing an extended dataset of vertical profiles in both stable and convective boundary-layer conditions. These vertical profiles were used to estimate an experimentally retrieved mixing height (MH). The MM5 meteorological model was also used to simulate the atmospheric dispersion characteristics for the same period, using a variety of different boundary-layer and land surface parameterization schemes (Medium-Range Forecast; high-resolution Blackadar; Gayno–Seaman; and Pleim–Chang). The model simulated MHs were compared among themselves, and then with that measured from balloon soundings. MRF parameterization represented the best compromise solution to simulate increasing MHs in the Po Valley. The MM5 simulations showed the regional character of meteorological forcing on PM ground-concentrations in the Po Valley.},
keywords = {}
}

@article{Belis20117266,
title = {Sources for PM air pollution in the Po Plain, Italy: I. Critical comparison of methods for estimating biomass burning contributions to benzo(a)pyrene},
author = {C.A. Belis and J. Cancelinha and M. Duane and V. Forcina and V. Pedroni and R. Passarella and G. Tanet and K. Douglas and A. Piazzalunga and E. Bolzacchini and G. Sangiorgi and M.-G. Perrone and L. Ferrero and P. Fermo and B.R. Larsen},
url = {http://www.sciencedirect.com/science/article/pii/S1352231011008983},
issn = {1352-2310},
year = {2011},
date = {2011-01-01},
journal = {Atmospheric Environment},
volume = {45},
number = {39},
pages = {7266 - 7275},
abstract = {Particle-bound benzo(a)pyrene (B(a)P) constitutes an air pollution problem in many areas of Europe and has been linked to biomass burning (BB). The present study, conducted in 2007 and 2009 at ten stations in the North Italian Po Plain and Valtelline Valley, examines four methods for the quantification of BB contributions to particle-bound B(a)P using data for 61 predictor compounds in more than 700 ambient PM10 and PM2.5 samples. The study was carried out during the heating season – a period of the year with minimal volatilization and atmospheric degradation of B(a)P, which favour source apportionment by receptor modelling. The lowest estimates of the source contribution (SCE) from BB were obtained with the levoglucosan tracer method and multi-linear regression analysis of daily variations in B(a)P concentrations using levoglucosan as the main predictor in combination with a few other predictors including gaseous pollutants and meteorological data. The standard uncertainty of these methods was driven by the uncertainty in the BB emission factor for levoglucosan and mounted to 90% (1 σ). Positive matrix factorization (PMF), using only PAH congeners as predictors, did not produce factors interpretable as emission sources. However, PMF utilizing a broad range of predictor compounds afforded five factors with compositions similar to emission sources. The yielded B(a)P SCEs for BB agreed well with results of chemical mass balance modelling (CMB). Both receptor models gave good predictions (p) of the observed (o) B(a)P concentrations (PMF: p/o = 89 ± 9%, CMB: p/o = 114 ± 17%) with lower uncertainties than the tracer methods (CMB 60%; PMF 54%; 1 σ). The average BB SCEs (mean ± 95% confidence interval) from these models were: 1.0 ± 0.4 ng m−3 at a kerbside in Milan, 1.0 ± 0.2 ng m−3 at six urban background stations in the Po Plain, 0.7 ± 0.3 ng m−3 at two rural background stations in the Po Plain, and 2.1 ± 1.1 ng m−3 at an urban background station in the Valtelline Valley representing 74 ± 32%, 79 ± 18%, 85 ± 33%, and 84 ± 46% of all modelled B(a)P sources, respectively.},
keywords = {}
}

@article{Sangiorgi20113545,
title = {Vertical distribution of hydrocarbons in the low troposphere below and above the mixing height: Tethered balloon measurements in Milan, Italy},
author = {G. Sangiorgi and L. Ferrero and M.G. Perrone and E. Bolzacchini and M. Duane and B.R. Larsen},
url = {http://www.sciencedirect.com/science/article/pii/S0269749111004453},
issn = {0269-7491},
year = {2011},
date = {2011-01-01},
journal = {Environmental Pollution},
volume = {159},
number = {12},
pages = {3545 - 3552},
abstract = {A novel approach for measuring vertical profiles of HCs and particle number concentrations was described and applied in the low troposphere over Milan (Italy) during typical spring and summer days. Particle profiles yielded nearly homogeneous concentrations below the mixing height, with level-to-ground concentration ratios of 92–97%, while HCs showed a more pronounced decrease (74–95%). Vertical mixing and photochemical loss of HCs were demonstrated to cause these gradients. Much lower concentrations were observed for the profiles above the mixing height, where the HC mixtures showed also a different composition, which was partially explained by the horizontal advection of air with HC sources different to those prevailing at the site. The application of pseudo-first order kinetics for reactions between HCs and the hydroxyl radical allowed for the estimation of the vertical mixing time scale in the order of 100 ± 20 min.},
keywords = {}
}

@article{Ferrero20112824,
title = {Vertical profiles of aerosol absorption coefficient from micro-Aethalometer data and Mie calculation over Milan},
author = {L. Ferrero and G. Mocnik and B.S. Ferrini and M.G. Perrone and G. Sangiorgi and E. Bolzacchini},
url = {http://www.sciencedirect.com/science/article/pii/S0048969711003792},
issn = {0048-9697},
year = {2011},
date = {2011-01-01},
journal = {Science of The Total Environment},
volume = {409},
number = {14},
pages = {2824 - 2837},
abstract = {Vertical profiles of aerosol number–size distribution and black carbon (BC) concentration were measured between ground-level and 500 m AGL over Milan. A tethered balloon was fitted with an instrumentation package consisting of the newly-developed micro-Aethalometer (microAeth® Model AE51, Magee Scientific, USA), an optical particle counter, and a portable meteorological station. At the same time, PM2.5 samples were collected both at ground-level and at a high altitude sampling site, enabling particle chemical composition to be determined. Vertical profiles and PM2.5 data were collected both within and above the mixing layer. Absorption coefficient (babs) profiles were calculated from the Aethalometer data: in order to do so, an optical enhancement factor (C), accounting for multiple light-scattering within the filter of the new microAeth® Model AE51, was determined for the first time. The value of this parameter C (2.05 ± 0.03 at λ = 880 nm) was calculated by comparing the Aethalometer attenuation coefficient and aerosol optical properties determined from OPC data along vertical profiles. Mie calculations were applied to the OPC number–size distribution data, and the aerosol refractive index was calculated using the effective medium approximation applied to aerosol chemical composition. The results compare well with AERONET data. The BC and babs profiles showed a sharp decrease at the mixing height (MH), and fairly constant values of babs and BC were found above the MH, representing 17 ± 2% of those values measured within the mixing layer. The BC fraction of aerosol volume was found to be lower above the MH: 48 ± 8% of the corresponding ground-level values. A statistical mean profile was calculated, both for BC and babs, to better describe their behaviour; the model enabled us to compute their average behaviour as a function of height, thus laying the foundations for valid parametrizations of vertical profile data which can be useful in both remote sensing and climatic studies.},
keywords = {}
}