ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-10-3915-2010 Vertically-resolved particle size distribution within and above the mixing layer over the Milan metropolitan area Ferrero L. 1 Perrone M. G. 1 Petraccone S. 1 Sangiorgi G. 1 Ferrini B. S. 1 Lo Porto C. 1 Lazzati Z. 1 Cocchi D. 2 Bruno F. 2 Greco F. 2 Riccio A. 3 Bolzacchini E. 1 POLARIS research centre, Department of Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza 1, 20126, Milano, Italy Department of Statistics "P. Fortunati", University of Bologna, Via delle Belle Arti 41, 40126, Bologna, Italy Department of Applied Science, University "Parthenope", Centro Direzionale, Isola C4, 80143, Napoli, Italy 27 04 2010 10 8 3915 3932 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys.net/10/3915/2010/acp-10-3915-2010.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/10/3915/2010/acp-10-3915-2010.pdf

Vertical aerosol profiles were directly measured over the city of Milan during three years (2005–2008) of field campaigns. An optical particle counter, a portable meteorological station and a miniaturized cascade impactor were deployed on a tethered balloon. More than 300 vertical profiles were measured, both in winter and summer, mainly in conditions of clear, dry skies. <br><br> The mixing height was determined from the observed vertical aerosol concentration gradient, and from potential temperature and relative humidity profiles. Results show that inter-consistent mixing heights can be retrieved highlighting good correlations between particle dispersion in the atmosphere and meteorological parameters. Mixing height growth speed was calculated for both winter and summer showing the low potential atmospheric dispersion in winter. <br><br> Aerosol number size distribution and chemical composition profiles allowed us to investigate particle behaviour along height. Aerosol measurements showed changes in size distribution according to mixing height. Coarse particle profiles (<i>d</i><sub><i>p</i></sub>>1.6 &mu;m) were distributed differently than the fine ones (<i>d</i><sub><i>p</i></sub><1.6 &mu;m) were, at different heights of the mixing layer. The sedimentation process influenced the coarse particle profiles, and led to a reduction in mean particle diameter for those particles observed by comparing data above the mixing height with ground data (&minus;14.9&plusmn;0.6% in winter and &minus;10.7&plusmn;1.0% in summer). Conversely, the mean particle diameter of fine particles increased above the mixing height under stable atmospheric conditions; the average increase, observed by comparing data above the mixing height with ground data, was +2.1&plusmn;0.1% in winter and +3.9&plusmn;0.3% in summer. A hierarchical statistical model was created to describe the changes in the size distribution of fine particles along height. The proposed model can be used to estimate the typical vertical profile characterising launches within pre-specified groups starting from: aerosol size and meteorological conditions measured at ground-level, and a mixing height estimation. The average increase of fine particle diameter, estimated on the basis of the model, was +1.9&plusmn;0.5% in winter and +6.1&plusmn;1.2% in summer, in keeping with experimental findings.

 References Aitchison, J.: The Statistical Analysis of Compositional Data, New York, USA, Chapman & Hall, 416 pp., 1986. Amiridis, V., Melas, D., Balis, D. S., Papayannis, A., Founda, D., Katragkou, E., Giannakaki, E., Mamouri, R. E., Gerasopoulos, E., and Zerefos, C.: Aerosol Lidar observations and model calculations of the Planetary Boundary Layer evolution over Greece, during the March 2006 Total Solar Eclipse, Atmos. Chem. Phys., 7, 6181–6189, 2007. Angelini F., Barnaba F., Landi T.C., Caporaso L., and Gobbi G.P.: Study of atmospheric aerosols and mixing layer by lidar. Radiat. Prot. Dosim., 137, No 3-4, 275-279, 2009. Baars H., Ansmann A., Engelmann R., and Althausen D.: Continuous monitoring of the boundary-layer top with lidar. Atmos. Chem. Phys., 8, 7281–7296, 2008. Billheimer, D., Guttorp, P., Fagan, W. (2001). Statistical Interpretation of Species Composition. J. Am. Stat. Assoc., 96, 1205-1214. Bruno F. and Greco F.: Clustering compositional data trajectories, in: Proceedings of CODAWORK'08, edited by: Daunis-i-Estadella, J. and Martín-Fernández, J. A.,The 3rd Compositional Data Analysis Workshop, 27–30 May, University of Girona, Girona (Spain), CD-ROM (ISBN: 978-84-8458-272-4), 11 pp., 2008. Campanelli, M., Delle Monache, L., Malvestuto, V., and Olivieri, B.: On the correlation between the depth of the boundary layer and the columnar aerosol size distribution, Atmos. Environ., 37, 4483–4492, 2003. Corrigan, C. E., Roberts, G. C., Ramana, M. V., Kim D., and Ramanathan, V.: Capturing vertical profiles of aerosols and black carbon over the Indian Ocean using autonomous unmanned aerial vehicles, Atmos. Chem. Phys., 8, 737–747, 2008. Di Nicolantonio, W., Cacciari, A., Bolzacchini, E., Ferrero, L., Volta, M., and Pisoni, E.: MODIS aerosol optical properties over north Italy for estimating surface-level PM$_2.5$, Proc. Envisat Symposium 2007, Montreux, Switzerland, 23–27 April 2007 (ESA SP-636, July 2007), http://envisat.esa.int/envisatsymposium/proceedings/posters/3P5/464392wd.pdf, 2007. Di Nicolantonio, W., Cacciari, A., Petritoli, A., Carnevale, C., Pisoni, E., Volta, M. L., Stocchi, P., Curci, G., Bolzacchini, E., Ferrero, L., Ananasso, C., and Tomasi, C.: MODIS and OMI satellite observations supporting air quality monitoring, Radiat. Prot. Dosim., 137(3–4), 280–287, 2009. Doherty, S. J., Anderson, T. L., and Charlson, R. J.: Measurement of the lidar ratio for atmospheric aerosols with a 180&deg; backscatter nephelometer, Appl. Opt., 38(9), 1823–1832, 1999. Dubovik, O., Smirnov, A., Holben, B. N., King, M. D., Kaufman, Y. J., Eck, T. F., and Slutsker, I.: Accuracy assessments of aerosol optical properties retrieved from Aerosol Robotic Network (AERONET): Sun and sky radiance measurements, J. Geophys. Res. 105, 9791–9806, 2000. Engel-Cox, J. A., Hoff, R. M., Rogers, R., Dimmick, F., Rush, A. C., Szykman, J. J., Al-Saadi, J., Chu, D. A., Erica, R. Z.: Integrating lidar and satellite optical depth with ambient monitoring for 3-dimensional particulate characterization, Atmos. Environ., 40, 8056–8067, 2006. Eresmaa, N., Karpinnen, A., Joffre, S. M., Räsänen, J., and Talvitie, H.: Mixing height determination by ceilometer, Atmos. Chem. Phys., 6, 1485–1493, 2006. Ferrero, L., Bolzacchini, E., Petraccone S., Perrone, M. G., Sangiorgi, G., Lo Porto, C., Lazzati, Z., and Ferrini, B.: Vertical profiles of particulate matter over Milan during winter 2005/2006, Fresen. Envion. Bull., 16(6), 697–700, 2007. % %Ferrero, L., Bolzacchini, E., Perrone, M. G., Petraccone, S., %Sangiorgi, G., Lo Porto, C., Ferrini, B. S., Lazzati, Z., Riccio, A., %Previtali, E., Clemenza, M., Bruno, F., Cocchi, D., and Greco, F.: %Influence of the Mixing Layer on the concentration and size-distribution of %Particulate Matter over Milan, EAC2007, Salzburg, http://www.gaef.de/EAC2007/, 2007b. Ferrero, L., Bolzacchini, E., Perrone, M. G., Sangiorgi, G., Lo Porto, C., Ferrini, B. S., Lazzati, Z., and Petraccone, S.: Strumentazione ad ultrasuoni per la caratterizzazione chimica del particolato atmosferico, LAB, Anno XIII, Ottobre 2008, in Italian, 2008. Fischer, B., Kukkonen, J., Piringer, M., Rotach, M. W., and Schatzmann, M.: Meteorology applied to urban air pollution problems: concepts from COST 715, Atmos. Chem. Phys., 6, 555–564, 2006. Gobbi, G., Barnaba, F., and Ammanato, L.: The vertical distribution of aerosols, Saharan dust and cirrus clouds in Rome (Italy) in the year 2001, Atmos. Chem. Phys., 4, 351–359, 2004. Hayasaka, T., Meguro, Y., Sasano, Y., and Takamura, T.: Stratification and size distribution of aerosols from simultaneous measurements with a lidar, a sunphotometer, and an aureolameter. Appl. Optics, 37, 961–970, 1998. Hinds, W. C.: Aerosol Technology, Wiley-Interscience edition, 1999. Holtslag, A. A. M., De Bruin, E. I. F., and Pan, H.-L.: A high resolution air mass transformation model for short range weather forecasting, Mon. Weather Rev., 118, 1561–1575, 1990. Holzworth, C. G.: Mixing depths, wind speeds and air pollution potential for selected locations in the United States, J. Appl. Meteorol. 6, 1039–1044, 1967. IPCC: Climate Change 2007, http://www.ipcc.ch/publications_and_data/ar4/wg1/en/contents.html, 2007. Kaufman, Y. J., and Fraser, R. S.: Light Extinction by Aerosols During Summer Air Pollution, J. Appl. Meteorol., 22, 1694–1706, 1983. Kaufman, Y. J., Tanré, D., and Boucher, O.: A satellite view of aerosols in the climate system, Nature, 419, 215–223, 2002. Kim, S. W., Yoon, S. C., Won, J. G., and Choi, S. C.: Ground-based remote sensing measurements of aerosol and ozone in an urban area: A case study of mixing height evolution and its effect on ground-level ozone concentrations, Atmos. Environ., 41, 7069–7081, 2007. Koren, I., Kaufman, Y. J., Remer, L. A., and Martins, J. V.: Measurments of the effect of amazon smoke on inhibition of cloud formation, Scienze, 303, 1342–1345, 2004. Kulmala, M., Laakso, L., Lehtinen, K. E. J., Riipinen, I., Dal Maso, M., Anttila, T., Kerminen, V. M., Hõrrak, U., Vana, M., and Tammet, H.: Initial steps of aerosol growth, Atmos. Chem. Phys., 4, 2553–2560, 2004. Laakso, L., Grönholm, T., Kulmala, L., Haapanala, S., Hirsikko, A., Lovejoy, E. R., Kazil, J., Kurtén, T., Boy, M., Nilsson, E. D., Sogachev, A., Riipinen, I., Stratmann, F., and Kulmala, M.: Hot-air balloon as a platform for boundary layer profile measurements during particle formation, Boreal Environ. Res., 12, 279–294, 2007. Levy, R. C., Remer, L. A., and Kaufman, Y. J.: Effects of neglecting polarization on the MODIS aerosol retrieval over land, IEEE T. Geosci. Remote Sens., 42(11), 2576–2583, 2004. Levy, R. C., Remer, L. A., Mattoo, S., Vermote, E. F., and Kaufman, Y. J.: Second generation operational algorithm: Retrieval of aerosol properties over land from inversion of Moderate Resolution Imaging Spectroradiometer spectral reflectance, J. Geophys. Res., 112, D13211, doi:10.1029/2006JD007811, 2007. Liu, Y., Sarnat, J. A., Kilaru, V., Jacob, D. J., and Koutrakis, P.: Estimating ground-level PM$_2.5$ in the Eastern United States using satellite remote sensing. Environ. Sci. Technol., 39, 3269–3278, 2005. Liu Y., Franklin M., Kahn R., Koutrakis P.: Using aerosol optical thickness to predict ground-level PM$_2.5$ concentrations in the St. Louis area: A comparison between MISR and MODIS. Remote Sens. Environ., 107, 33–44, 2007. Maletto A., McKendry, I. G., and Strawbridge, K. B.: Profiles of particulate matter size distributions using a balloon-borne lightweight aerosol spectrometer in the planetary boundary layer, Atmos. Environ., 37, 661–670, 2003. Matzuki, A., Iwasaka, Y., Shi, G.-Y., Chen, H.-B., Osada, K., Zhang, D., Kido, M., Inomata, Y., Kim, Y.-S., Trochkine, D., Nishita, C., Yamada, M., Nagatani, T., and Nakata, H.: Heterogeneous Sulphate formation on dust surface and its dependence on mineralogy: balloon-borne observations from balloon-borne measurements in the surface atmosphere of Beijing, China. Water Air Soil Poll., 5, 101–132, 2005. McKendry, I. G. and Lundgren J.: Tropospheric layering of ozone in regions of urbanized comple x and/or coastal terrain: a review, Prog. Phys. Geog., 24, 359–384, 2000. McKendry, I. G., Sturman, A. P., and Vergeiner, J.: Vertical profiles of particulate matter size distributions during winter domestic burning in Christchurch, New Zealand, Atmos. Environ., 38, 4805–4813, 2004. Menut, L., Flamant, C., Pelon, J., and Flamant, P. H.: Urban boundary-layer height determination from lidar measurements over the Paris area, Appl. Opt., 38, 945–954, 1999. Morgan, W. T., Allan, J. D., Bower, K. N., Capes, G., Crosier, J., Williams, P. I., and Coe, H.: Vertical distribution of sub-micron aerosol chemical composition from North-Western Europe and the North-East Atlantic, Atmos. Chem. Phys., 9, 5389–5401, 2009. Penner, J. E., Andreae, M., Annegarn, H., Barrie, L., Feichter, J., Hegg, D., Jayaraman, A., Leaitch, R., Murphy, D., Nganga, J., and Pitari, G.: Aerosols, their Direct and Indirect Effects, In Climate Change 2001: The Scientific Basis, Cambridge University Press, Cambridge, UK, 291–348, 2001. Palchetti, L., Bianchini, G., Carli, B., Cortesi, U., and Del Bianco, S.: Measurement of the water vapour vertical profile and of the Earth's outgoing far infrared flux, Atmos. Chem. Phys., 8, 2885–2894, 2008. Perrone, M. G., Gualtieri, M., Ferrero, L., Lo Porto, C., Udisti, R., Bolzacchini, E., and Camatini, M.: Seasonal variations in chemical composition and \textitin- vitro biological effects of fine PM from Milan, Chemosphere, 78, 1368–1377, 2010. Pope, C. and Dockery, D.: Chapter 31. Epidemiology of particle effects, edited by: Holgate, S. T., Koren, H. S., Samet, J. M., and Maynard, R. L., in: Air pollution and health, San Diego, USA, Academic Press, 673–705, 1999. Raes, F., Van Dingenen, R., Vignati, E., Wilson, J., et al.: Formation and cycling of aerosols in the global troposphere, Atmos. Environ., 34, 4215–4240, 2000. Rodriguez, S., Van Dingenen, R., Putaud, J. P., Dell'Acqua, A., Pey, J., Querol, X., Alastuey, A., Chenery, S., Ho, K. F., Harrison, R., Tardivo, R., Scarnato, B., and Gemelli, V.: A study on the relationship between mass concentration, chemistry and number size distribution of urban fine aerosol in Milan, Barcelona and London, Atmos. Chem. Phys., 7, 2217–2232, 2007. Rojas-Bracho, L., Suh, H., and Koutrakis, P.: Relationships among personal, indoor, and outdoor fine and coarse particle concentrations for individuals with COPD, J. Expo. Anal. Env. Epid., 10(3), 294–306, 2000. Sarigiannis, D. A., Soulakellis, N. A., and Sifakis, N. I.: Information fusion for computational assessment of air quality and health effects, Photogramm. Eng. Remote Sens., 70(2) 235–245, 2004. Schneider, J., Hings, S. S., Hock, B. N., Weimer, S., Borrmann, S., Fiebig, M., Petzold, A., Busen, R., and Kärcher, B.: Aircraft-based operation of an aerosol mass spectrometer: Measurements of tropospheric aerosol composition, J. Aerosol Sci., 37, 839–857, 2006. Schwartz, J., Dockery, D., and Neas, L.: Is daily mortality associated specifically with fine particles?, J. Air Waste Manage., 46(10), 927–939, 1996. Seibert, P, Beyrich, F., Gryning, S. E., Joffre, S., Rasmussen, A., and Tercier, P.: Review and intercomparison of operational methods for the determination of the mixing height, Atmos. Environ., 34, 1001–1027, 2000. Seinfeld, J. H. and Pandis, S. N.: Atmospheric chemistry and physics – From air pollution to climate change, Wiley-Interscience edition, 1998. Schaap, M., Apituley, A., Timmermans, R. M. A., Koelemeijer, R. B. A., and De Leeuw, G.: Exploring the relation between aerosol optical depth and PM$_2.5 $at Cabauw, The Netherlands, Atmos. Chem. Phys., 9, 909–925, 2009. Sjogren, S., Gysel, M., Weingartner, E., Alfarra, M. R., Duplissy J., Cozic J., Crosier, J., Coe, H., and Baltensperger, U.: Hygrosopicity of the submicrometer aerosol at the high-alpine site Junfrajoch, 3580 m a.s.l., Switzerland, Atmos. Chem. Phys., 8, 5715–5729, 2008. Spiegelhalter, D. J., Best, N., Carlin, B. P., and Van der Linde, A.: Bayesian measures of model complexity and fit (with discussion), J. R. Stat. Soc., Series B, 64, 583–639 2002. Spiegelhalter, D., Thomas, A., and Best, N.: WinBugs: Bayesian inference using Gibbs sampler, Manual Version 1.2. Imperial College, London and Medical Research Council Biostatistics Unit, Cambridge, 1998. Stratmann, F., Siebert, H., Spindler, G., Wehner, B., Althausen, D., Heintzenberg, J., Hellmuth, O., Rinke, R., Schmieder, U., Seidel, C., Tuch, T., Uhrner, U., Wiedensohler, A., Wandinger, U., Wendisch, M., Schell, D., and Stohl, A.: New-particle formation events in a continental boundary layer: first results from the SATURN experiment, Atmos. Chem. Phys., 3, 1445–1459, 2003. Taubman, B. F., Hains, J. C., Thompson, A. M., Marufu, L. T., Doddrige, B. G., Stehr, J. W., Piety, C. A., and Dickerson, R. R..: Aircraft vertical profiles of trace gas and aerosol pollution over the mid-Atlantic United States: statistics and meteorological cluster analysis, J. Geophys. Res., 111, D10S07, doi:10.1029/2005JD006196, 2006. Troen, I. and Mahrt, L.: A simple model of the atmospheric boundary layer model; sensitivity to surface evaporation. Bound.-Lay. Meteorol., 37, 129–148, 1986. Van Dingenen, R., Raes, F., Putaud, J. P., Baltensperger, U., et al.: A European aerosol phenomenology-1: physical characteristics of particulate matter at kerbside, urban, rural and background sites in Europe, Atmos. Environ., 38, 2561–2577, 2004. Velasco, E., Márquez, C., Bueno, E., Bernabé, R. M., Sánchez, A., Fentanes, O., Wöhrnschimmel, H., C'ardenas, B., Kamilla, A., Wakamatsu, S., and Molina, L. T.: Vertical distribution of ozone and VOCs in the low boundary layer of Mexico City, Atmos. Chem. Phys., 8, 3061–3079, 2008. Vecchi, R., Marcazzan, G., Valli, G., Cerini, M., and Antoniazzi, C.: The role of atmospheric dispersion in the seasonal variation of PM$_1$ and PM$_2.5$ concentration and composition in the urban area of Milan (Italy), Atmos. Environ., 38, 4437–4446, 2004. Wang, J. and Christofer, S. A.: Intercomparison between satellite-derived aerosol optical thickness and PM$_2.5$ mass: Implications for air quality studies, Geophys. Res. Lett., 30(21), 2095, doi:10.1029/2003GL018174, 2003. Weingartner, E., Burtscher, H., and Baltensperger, U.: Hygroscopic properties of carbon and diesel soot particles, Atmos. Environ., 31(15), 2311–2327, 1997. Wiegner, M., Emeis, S., Freudenthaler, V., Heese, B., Junkermann, W., Münkel, C., Schäfer, K., Seefeldner, M., and Vogt, S.: Mixing layer height over Munich, Germany: Variability and comparisons of different methodologies, J. Geophys. Res., 111, D13201, doi:10.1029/2005JD006593, 2006. Wikle, C. K., Berliner, L. M., and Cressie, N.: Hierarchical Bayesian space-time models, Environ. Eco. Stati., 5, 117–154, 1998.