Carbonaceous Aerosols in the Atmosphere

Contini, Daniele; Vecchi, R.; Viana, Mar

doi:10.3390/atmos9050181

Cited by 64 publications

(33 citation statements)

References 46 publications

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“…Carbonaceous aerosols (organic carbon, OC; organic matter, OM; elemental or black carbon, EC or BC, respectively) constitute the dominant component of aerosols in the urban environment and are mainly classified in the fine-mode fraction. They include toxic compounds and induce adverse impacts on the human respiratory and circulatory systems [1][2][3][4]. EC is emitted from the incomplete combustion of fossil fuels and any kind of biomass and, being chemically inert, it can be sustained in the atmosphere for several days, contributing to a large degree in atmospheric warming [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Carbonaceous Aerosols in Contrasting Atmospheric Environments in Greek Cities: Evaluation of the EC-tracer Methods for Secondary Organic Carbon Estimation

et al. 2020

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This study examines the carbonaceous-aerosol characteristics at three contrasting urban environments in Greece (Ioannina, Athens, and Heraklion), on the basis of 12 h sampling during winter (January to February 2013), aiming to explore the inter-site differences in atmospheric composition and carbonaceous-aerosol characteristics and sources. The winter-average organic carbon (OC) and elemental carbon (EC) concentrations in Ioannina were found to be 28.50 and 4.33 µg m−3, respectively, much higher than those in Heraklion (3.86 µg m−3 for OC and 2.29 µg m−3 for EC) and Athens (7.63 µg m−3 for OC and 2.44 µg m−3 for EC). The winter OC/EC ratio in Ioannina (6.53) was found to be almost three times that in Heraklion (2.03), indicating a larger impact of wood combustion, especially during the night, whereas in Heraklion, emissions from biomass burning were found to be less intense. Estimations of primary and secondary organic carbon (POC and SOC) using the EC-tracer method, and specifically its minimum R-squared (MRS) variant, revealed large differences between the sites, with a prevalence of POC (67–80%) in Ioannina and Athens and with a larger SOC fraction (53%) in Heraklion. SOC estimates were also obtained using the 5% and 25% percentiles of the OC/EC data to determine the (OC/EC)pri, leading to results contrasting to the MRS approach in Ioannina (70–74% for SOC). Although the MRS method provides generally more robust results, it may significantly underestimate SOC levels in environments highly burdened by biomass burning, as the fast-oxidized semi-volatile OC associated with combustion sources is classified in POC. Further analysis in Athens revealed that the difference in SOC estimates between the 5% percentile and MRS methods coincided with the semi-volatile oxygenated organic aerosol as quantified by aerosol mass spectrometry. Finally, the OC/Kbb+ ratio was used as tracer for decomposition of the POC into fossil-fuel and biomass-burning components, indicating the prevalence of biomass-burning POC, especially in Ioannina (77%).

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Section: Introductionmentioning

confidence: 99%

Carbonaceous Aerosols in Contrasting Atmospheric Environments in Greek Cities: Evaluation of the EC-tracer Methods for Secondary Organic Carbon Estimation

et al. 2020

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“…The carbonaceous composition of PM 2.5 has been studied at different sites in Italy [42][43][44][45][46][47]. However, the Mediterranean basin, especially the southern part of the Italian peninsula, still suffers from a lack of observations [48], despite the growing number of new studies [49][50][51][52]. Furthermore, only a few 14 C source apportionment studies have been conducted in Italy, all of them at northern continental sites [26,53,54], whereas none, to our knowledge, focused on the southern part.…”

Section: Introductionmentioning

confidence: 99%

High Contribution of Biomass Combustion to PM2.5 in the City Centre of Naples (Italy)

et al. 2019

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A better knowledge of the local and regional sources of the atmospheric particulate matter provides policy makers with the proper awareness when acting to improve air quality, in order to protect public health. A source apportionment study of the carbonaceous aerosol in Naples (Italy) is presented here, in order to improve this understanding in a vulnerable urban area. The aim of this study is quantifying directly fossil and non-fossil contributions to carbonaceous aerosol, by means of radiocarbon measurements. This is the first time that such an approach is implemented in this area. Fine particles with diameter ≤ 2.5 µm (PM2.5) were collected daily on top of a building in the city center, from November 2016 until January 2017. The carbonaceous aerosol was separated into organic carbon (OC) and elemental carbon (EC), by a two-step thermal desorption method. Subsequent radiocarbon analysis enabled the partitioning of the major sources of carbonaceous aerosol into fossil and non-fossil ones by applying radiocarbon isotopic mass balance. The PM2.5 concentration was on average 29 ± 3 µg⁄m3 (mean ± standard error; n = 18), with a maximum of 68.6 ± 0.7 µg⁄m3 on a day when air masses back-trajectories suggest a local origin and stagnant airflow conditions in the region. The carbonaceous component accounts for roughly half of the PM2.5 mass. Fossil fuel emissions are a minor source of OC (23%), but the dominant source of EC (66%), which is directly emitted during combustion processes. However, overall only 30% of the total carbon is of fossil origin, accounting for 14% of PM2.5 mass. Surprisingly, a comparable contribution is due to primary biomass burning carbon, which accounts in total for 15% of PM2.5 mass. Traffic pollution, the main cause of fossil fuel emissions in urban areas, is a significant, but not the predominant source of carbonaceous particle concentration. These findings support the conclusion of a predominant contribution from non-fossil sources to the carbon in airborne particulate matter, which policy makers should take into account when planning mitigation strategies to improve urban air quality.

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“…Carbonaceous aerosols are composed of organic aerosols and refractory light-absorbing components, generally referred to as elemental carbon or black carbon [1]. Organic aerosols contain thousands of organic compounds and account for 20-50% of the total fine aerosol mass at mid-latitudes [2,3].…”

Section: Introductionmentioning

confidence: 99%

Source-Based Size-Resolved Optical Properties of Carbonaceous Aerosols

et al. 2021

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In this study, the source-based optical properties of polydisperse carbonaceous aerosols were determined from PM2.5 concentrations measured at a Global Atmospheric Watch station in South Korea. The extinction and absorption coefficients of carbonaceous aerosols were calculated using the Mie theory and assuming a lognormal size distribution. Based on the mass concentration from the EPA’s Positive Matrix Factorization (PMF) receptor model, which considers five source identification and apportionment factors (biogenic source, local biomass burning, secondary organic aerosol, transported biomass burning, and mixed sources), the source-based size-resolved mass extinction and absorption efficiencies were estimated for each source using a multilinear regression model. The results show that the source-based optical properties depend on the aerosol size and physicochemical characteristics of the chemical compounds. The long-range transport of biomass burning (LBB) aerosol, which has a mass concentration of 20%, holds a 12.1–23.1% total extinction efficiency—depending on the size and refractive index—in the range of 0.1–0.5 μm in geometric mean diameter and humic-like substances (HULIS) imaginary refractive index of 0.006–0.3. Biogenic sources of aerosols with small diameters have higher mass absorption efficiencies (MAE) than other sources, depending on the size and refractive index.

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Carbonaceous Aerosols in the Atmosphere

Abstract: Scientific understanding of the processes involving carbonaceous aerosols in atmosphere is extremely important for both the climate and human health. This explains the increasing scientiﬁc interest in characterising these chemical species [1,2].[...]

Cited by 64 publications

References 46 publications

Carbonaceous Aerosols in Contrasting Atmospheric Environments in Greek Cities: Evaluation of the EC-tracer Methods for Secondary Organic Carbon Estimation

Carbonaceous Aerosols in Contrasting Atmospheric Environments in Greek Cities: Evaluation of the EC-tracer Methods for Secondary Organic Carbon Estimation

High Contribution of Biomass Combustion to PM2.5 in the City Centre of Naples (Italy)

Source-Based Size-Resolved Optical Properties of Carbonaceous Aerosols

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