Source apportionment of carbonaceous chemical species to fossil fuel combustion, biomass burning and biogenic emissions by a coupled radiocarbon–levoglucosan marker method

摘要

An intensive aerosol measurement and sample collectioncampaign was conducted in central Budapest in a mild winter for 2 weeks.The online instruments included an FDMS-TEOM, RT-OC/EC analyser, DMPS, gaspollutant analysers and meteorological sensors. The aerosol samples werecollected on quartz fibre filters by a low-volume sampler using the tandemfilter method. Elemental carbon (EC), organic carbon (OC), levoglucosan,mannosan, galactosan, arabitol and mannitol were determined, and radiocarbonanalysis was performed on the aerosol samples. Median atmosphericconcentrations of EC, OC and PM mass were 0.97, 4.9 and 25 µg m, respectively. The EC and organic matter (1.6  ×  OC)accounted for 4.8 and 37 %, respectively, of the PM mass.Fossil fuel (FF) combustion represented 36 % of the total carbon(TC  =  EC + OC) in the PM size fraction. Biomass burning (BB) was amajor source (40 %) for the OC in the PM size fraction, and asubstantial source (11 %) for the PM mass. We propose and applyhere a novel, straightforward, coupled radiocarbon–levoglucosan markermethod for source apportionment of the major carbonaceous chemical species.The contributions of EC and OC from FF combustion (EC and OC)to the TC were 11.0 and 25 %, respectively, EC and OC from BB(EC and OC) were responsible for 5.8 and 34 %,respectively, of the TC, while the OC from biogenic sources (OC)made up 24 % of the TC. The overall relative uncertainty of theOC and OC contributions was assessed to be up to 30 %,while the relative uncertainty for the other apportioned species is expectedto be below 20 %. Evaluation of the apportioned atmospheric concentrationsrevealed some of their important properties and relationships among them.EC and OC were associated with different FF combustionsources. Most EC was emitted by vehicular road traffic, while thecontribution of non-vehicular sources such as domestic and industrialheating or cooking using gas, oil or coal to OC was substantial. Themean contribution of BB to EC particles was smaller by a factor ofapproximately 2 than that of road traffic. The main formation processes ofOC, OC and OC from volatile organic compounds werejointly influenced by a common factor, which is most likely the atmosphericphotochemistry, while primary organic emissions can also be important.Technological improvements and control measures for various BB appliances,together with efficient education and training of their users, in particularon the admissible fuel types, offer an important potential for improving theair quality in Budapest, and likely in other cities as well.