Carbonaceous aerosols in Norwegian urban areas

Abstract

Abstract. Little is known regarding levels and source strength of carbonaceous aerosols in Scandinavia. In the present study, ambient aerosol (PM 10 and PM 2.5 ) concentrations of elemental carbon (EC), organic carbon (OC), waterinsoluble organic carbon (WINSOC), and water-soluble organic carbon (WSOC) are reported for a curbside site, an urban background site, and a suburban site in Norway in order to investigate their spatial and seasonal variations. Aerosol filter samples were collected using tandem filter sampling to correct for the positive sampling artefact introduced by volatile and semivolatile OC. Analyses were performed using the thermal optical transmission (TOT) instrument from Sunset Lab Inc., which corrects for charring during analysis. Finally, we estimated the relative contribution of OC from wood burning based on the samples content of levoglucosan.Levels of EC varied by more than one order of magnitude between sites, likely due to the higher impact of vehicular traffic at the curbside and the urban background sites. In winter, the level of particulate organic carbon (OC p ) at the suburban site was equal to (for PM 10 ) or even higher (for PM 2.5 ) than the levels observed at the curbside and the urban background sites. This finding was attributed to the impact of residential wood burning at the suburban site in winter, which was confirmed by a high mean concentration of levoglucosan (407 ng m −3 ). This finding indicates that exposure to primary combustion derived OC p could be equally high in residential areas as in a city center. It is demonstrated that OC p from wood burning (OC wood ) accounted for almost all OC p at the suburban site in winter, allowing a new estimate of the ratio TC p /levoglucosan for both PM 10 and PM 2.5 . Particulate carbonaceous material (PCM=Organic matter+Elemental matter) accounted for 46-83% of PM 10 at the sites studied, thus being the major fraction.

Quantifying black carbon from biomass burning by means of levoglucosan – a one-year time series at the Arctic observatory Zeppelin

“…wood type, type of appliance and flaming versus smoldering combustion, and consequently between geographical regions, we have allowed for a rather wide range in our calculations and adopted the range and approach reported by Yttri et al (2011a) (Tables 1 and 2). Consequently, the analytical method used to determine levoglucosan is self-consistent, as the method by Dye and Yttri (2005) was applied both in the present study as well as in that of Yttri et al (2009), from which the emission ratio range listed in Yttri et al (2011a) was derived.…”

Technical Note: On the effect of water-soluble compounds removal on EC quantification by TOT analysis in urban aerosol samples

“…Water soluble compounds were removed washing portions of the high volume sampled filters using MilliQ (Millipore) water. Each portion of the filter was placed in a filtration assembly -similar to the one reported by Yttri et al (2009) suitably designed for this application. The washed area was 37 mm diameter wide (i.e.…”

Inter-comparison of source apportionment models for the estimation of wood burning aerosols during wintertime in an Alpine city (Grenoble, France)

“…For urban environments, Zdráhal et al (2002) estimated that wood burning emissions accounted for ∼35% of organic carbon (OC) in Ghent, Belgium, during a winter episode. Caseiro et al (2009), Yttri et al (2009) and Szidat et al (2006) also reported high contributions of wood burning organics to OC in Vienna (Austria), Oslo (Norway) and Zürich (Switzerland), i.e., ∼20%, ∼30% and ∼40% respectively for winter time at urban background sites. Finally, Favez et al (2009) suggested that residential wood burning emissions account for about 20±10% of total PM 2.5 in such a large city as Paris, France, during wintertime.…”