Hochschule für Technik und Umwelt FHNW

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  • Kein Vorschaubild vorhanden
    Publikation
    A European aerosol phenomenology - 1. physical characteristics of particulate matter at kerbside, urban, rural and background sites in Europe
    (Elsevier, 05/2004) Van Dingenen, Rita; Raes, Frank; Putaud, Jean-Philippe; Baltensperger, Urs; Charron, Aurélie; Facchini, Maria Cristina; Decesari, Stefano; Fuzzi, Sandro; Gehrig, Robert; Hansson, Hans-Christen; Harrison, Roy M.; Hüglin, Cristoph; Jones, Alan M.; Laj, Paolo; Lorbeer, Gundi; Maenhaut, Willy; Palmgren, Finn; Querol, Xavier; Rodriguez, Sergio; Schneider, Jürgen; ten Brink, Harry; Tunved, Peter; Tørseth, Kjetil; Wehner, Birgit; Weingartner, Ernest; Wiedensohler, Alfred; Wåhlin, Peter
    This paper synthesizes data on aerosol (particulate matter, PM) physical characteristics, which were obtained in European aerosol research activities at free-troposphere, natural, rural, near-city, urban, and kerbside sites over the past decade. It covers only two sites in the semi-arid Mediterranean area, and lacks data from Eastern Europe. The data include PM10 and/or PM2.5 mass concentrations, and aerosol particle size distributions. Such data sets are more comprehensive than those currently provided by air quality monitoring networks (e.g. EMEP, EUROAIRNET). Data available from 31 sites in Europe (called “The Network”) were reviewed. They were processed and plotted to allow comparisons in spite of differences in the sampling and analytical techniques used in various studies. A number of conclusions are drawn as follows: Background annual average PM10 and PM2.5 mass concentrations for continental Europe are 7.0±4.1 and 4.8±2.4 μg mˉ³, respectively. The EU 2005 annual average PM10 standard of 40 μg mˉ³ is exceeded at a few sites in The Network. At all near city, urban and kerbside sites, the EU 2010 annual average PM10 standard of 20 μg mˉ³, as well as the US-EPA annual average PM2.5 standard of 15 μg mˉ³ are exceeded. In certain regions, PM10 and PM2.5 in cities are strongly affected by the regional aerosol background. There is no “universal” (i.e. valid for all sites) ratio between PM2.5 and PM10 mass concentrations, although fairly constant ratios do exist at individual sites. There is no universal correlation between PM mass concentration on the one hand, and total particle number concentration on the other hand, although a ‘baseline’ ratio between number and mass is found for sites not affected by local emissions. This paper is the first part of two companion papers of which the second part describes chemical characteristics.
    01A - Beitrag in wissenschaftlicher Zeitschrift
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    Publikation
    Predicting hygroscopic growth using single particle chemical composition estimates
    (Wiley, 2014) Healy, Robert M.; Evans, Greg J.; Murphy, Michael; Jurányi, Zsófia; Tritscher, Torsten; Laborde, Marie; Weingartner, Ernest; Gysel, Martin; Poulain, Laurent; Kamilli, Katharina A.; Wiedensohler, Alfred; O'Connor, Ian P.; McGillicuddy, Eoin; Sodeau, John R.; Wenger, John C.
    Single particle mass spectral data, collected in Paris, France, have been used to predict hygroscopic growth at the single particle level. The mass fractions of black carbon, organic aerosol, ammonium, nitrate, and sulphate present in each particle were estimated using a combination of single particle mass spectrometer and bulk aerosol chemical composition measurements. The Zdanovskii‐Stokes‐Robinson (ZSR) approach was then applied to predict hygroscopic growth factors based on these mass fraction estimates. Smaller particles with high black carbon mass fractions and low inorganic ion mass fractions exhibited the lowest predicted growth factors, while larger particles with high inorganic ion mass fractions exhibited the highest growth factors. Growth factors were calculated for subsaturated relative humidity (90%) to enable comparison with hygroscopic tandem differential mobility analyzer measurements. Mean predicted and measured hygroscopic growth factors for 110, 165, and 265 nm particles were found to agree within 6%. Single particle‐based ZSR hygroscopicity estimates offer an advantage over bulk aerosol composition‐based hygroscopicity estimates by providing additional chemical mixing state information. External mixing can be determined for particles of a given diameter through examination of the predicted hygroscopic growth factor distributions. Using this approach, 110 nm and 265 nm particles were found to be predominantly internally mixed; however, external mixing of 165 nm particles was observed periodically when thinly coated and thickly coated black carbon particles were simultaneously detected. Single particle‐resolved chemical information will be useful for modeling efforts aimed at constraining cloud condensation nuclei activity and hygroscopic growth.
    01A - Beitrag in wissenschaftlicher Zeitschrift