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

Abstract

Abstract. An intensive aerosol measurement and sample collection campaign was conducted in central Budapest in a mild winter for 2 weeks. The online instruments included an FDMS-TEOM, RT-OC/EC analyser, DMPS, gas pollutant analysers and meteorological sensors. The aerosol samples were collected on quartz fibre filters by a low-volume sampler using the tandem filter method. Elemental carbon (EC), organic carbon (OC), levoglucosan, mannosan, galactosan, arabitol and mannitol were determined, and radiocarbon analysis was performed on the aerosol samples. Median atmospheric concentrations of EC, OC and PM 2.5 mass were 0.97, 4.9 and 25 µg m −3 , respectively. The EC and organic matter (1.6 × OC) accounted for 4.8 and 37 %, respectively, of the PM 2.5 mass. Fossil fuel (FF) combustion represented 36 % of the total carbon (TC = EC + OC) in the PM 2.5 size fraction. Biomass burning (BB) was a major source (40 %) for the OC in the PM 2.5 size fraction, and a substantial source (11 %) for the PM 10 mass. We propose and apply here a novel, straightforward, coupled radiocarbon-levoglucosan marker method for source apportionment of the major carbonaceous chemical species. The contributions of EC and OC from FF combustion (EC FF and OC FF ) to the TC were 11.0 and 25 %, respectively, EC and OC from BB (EC BB and OC BB ) were responsible for 5.8 and 34 %, respectively, of the TC, while the OC from biogenic sources (OC BIO ) made up 24 % of the TC. The overall relative uncertainty of the OC BIO and OC BB contributions was assessed to be up to 30 %, while the relative uncertainty for the other apportioned species is expected to be below 20 %. Evaluation of the apportioned atmospheric concentrations revealed some of their important properties and relationships among them. EC FF and OC FF were associated with different FF combustion sources. Most EC FF was emitted by vehicular road traffic, while the contribution of non-vehicular sources such as domestic and industrial heating or cooking using gas, oil or coal to OC FF was substantial. The mean contribution of BB to EC particles was smaller by a factor of approximately 2 than that of road traffic. The main formation processes of OC FF , OC BB and OC BIO from volatile organic compounds were jointly influenced by a common factor, which is most likely the atmospheric photochemistry, 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 particular on the admissible fuel types, offer an important potential for improving the air quality in Budapest, and likely in other cities as well.

Intra-regional transport of black carbon between the south edge of the North China Plain and central China during winter haze episodes

“…BC efficiently absorbs the solar spectrum with a weak dependence on wavelength; the absorption Ångström exponent (AAE) is used to describe this spectral dependence on absorption . The AAE value varies significantly from one source to another, i.e., the AAE values for fossil fuel combustion and biomass burning-derived BC are 1.0 and 2.0, respectively (Sandradewi et al, 2008). The BC source apportionment method was established based on the AAE (Sandradewi et al, 2008) and was verified using the 14 C method (Zotter et al, 2017).…”

“…The AAE value varies significantly from one source to another, i.e., the AAE values for fossil fuel combustion and biomass burning-derived BC are 1.0 and 2.0, respectively (Sandradewi et al, 2008). The BC source apportionment method was established based on the AAE (Sandradewi et al, 2008) and was verified using the 14 C method (Zotter et al, 2017). Black carbon source apportionment using the Aethalometer model is based on the assumption that the aerosol absorption coefficient is different from fossil fuel combustionderived BC (BC ff ) and biomass burning-derived BC (BC bb ).…”

“…Because the absorption coefficients at different wavelengths are different and the absorption of BC ff and BC bb follow different spectral dependencies. The Ångström exponents, α ff and α bb , are used to describe the dependencies of fossil fuel and biomass burning, respectively; the following equations are used (Sandradewi et al, 2008)…”

“…The broadly reported BC sources can be grouped into stationary sources (e.g., industrial emission), area sources (e.g., residential coal/wood combustion, open burning) and mobile sources (e.g., diesel engines) (Chow et al, 2011;Bond et al, 2013). To identify BC sources, several methods including the Aethalometer model, diagnosis ratios and radioactive carbon isotope analysis have been developed (Sandradewi et al, 2008;Verma et al, 2010;Zotter et al, 2017). Chow et al (2011) summarized the ratios of elemental carbon to PM 2.5 (expressed as percentage, %) from various sources, and these ratios have since been used to qualitatively describe BC sources (Y. .…”

“…The Aethalometer model is an alternative method, which can attribute BC to fossil fuel combustion and biomass burning. The source apportionment can be conducted using multi-wavelength BC data (Sandradewi et al, 2008;, and the validity of this method has been proven by comparison to the 14 C method (Zotter et al, 2017). Compared with other methods, the Aethalometer model can provide the high time resolution variations of BC source contributions (Kalogridis et al, 2018;, which can help with understanding the atmospheric behavior of BC, especially regarding the temporal variation.…”