scholarly journals Modeling Investigation of Brown Carbon Aerosol and Its Light Absorption in China

Atmosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 892
Author(s):  
Yong Zhu ◽  
Qiaoqiao Wang ◽  
Xiajie Yang ◽  
Ning Yang ◽  
Xurong Wang
Keyword(s):  
Uv Radiation ◽  
Biomass Burning ◽  
Exhaust Emissions ◽  
Absorption Efficiency ◽  
Carbonaceous Aerosol ◽  
Potential Contribution ◽  
Vehicle Exhaust ◽  
Brown Carbon ◽  
Residential Combustion ◽  
Equal Importance

Brown carbon (BrC) is a type of organic carbon with light-absorbing abilities, especially in ultraviolet (UV) radiation, which could significantly contribute to global warming. Observations have shown high BrC concentrations and absorption in China, suggesting potentially large BrC emissions. The potential contribution of fossil fuel combustion to BrC emission has been ignored in most previous studies. Here, we use GEOS-Chem to simulate BrC distribution and absorption in China, accounting for three major primary BrC sources: residential coal and biofuel combustion, vehicle exhausts, and open biomass burning. Based on the literature and related energy consumption data, we estimate the specific emission ratio of BrC versus BC, and BrC mass absorption efficiency (MAE) for each source. Combined with BC emission, total BrC emission in China is then estimated to be 3.42 Tg yr−1 in 2018, of which 71% is from residential combustion, 14% is from vehicle exhaust, and 15% is from open biomass burning. Residential combustion is the main source of surface BrC in China, accounting for 60% on average, followed by open biomass burning (23%) and vehicle exhaust emissions (17%). There is a clear seasonality in surface BrC concentrations with the maximum in winter (5.1 µg m−3), followed by spring (2.8 µg m−3), autumn (2.3 µg m−3), and summer (1.3 µg m−3). BrC AAOD at 365 nm ranges from 0.0017 to 0.060 in China, mainly dominated by residential combustion (73%), followed by open biomass burning (16%), and vehicle exhaust emissions (11%). It is also estimated that BrC accounts for 45–67% (52% on average) of total carbonaceous aerosol AAOD at 365 nm, implying an equal importance of BrC and BC regarding the absorption in UV radiation.

Brown carbon aerosol in urban Beijing: Significant contributions from biomass burning and secondary formation

2020 ◽  
Author(s):  
Ting Wang ◽  
Rujin Huang ◽  
Lu Yang ◽  
Wei Yuan ◽  
Yuquan Gong
Keyword(s):  
Biomass Burning ◽  
Light Absorption ◽  
Coal Combustion ◽  
Absorption Efficiency ◽  
Traffic Emission ◽  
Brown Carbon ◽  
Factorization Model ◽  
Secondary Formation ◽  
Vis Spectroscopy ◽  
The Impact

<p>Atmospheric brown carbon (BrC) has significant impact on Earth’s radiative budget. However, due to our very limited knowledge about the relationship between BrC light absorption and the associated sources, the estimation for radiative effects of BrC is still largely constrained. In this study, we combine ultraviolet−visible (UV−vis) spectroscopy measurements and chemical analyses of BrC samples collected from January to December 2015 in urban Beijing, to investigated the sources of atmospheric BrC. The multiple liner regression model was applied to apportion the contributions of individual primary and secondary organic aerosol (OA) source components to light absorption of BrC. Our results indicated that biomass burning emission and secondary formation are highly absorbing up to 500 nm, and their contributions increased with the wavelengths. In contrast, the contribution of traffic emission and coal combustion to total absorption decreased with the wavelength and the large contributions were mostly found at shorter wavelengths. Then the mass absorption efficiency (MAE) of major light-absorbing components were estimated, which can provide a support to estimate the impact of BrC from these sources on the climate. The positive matrix factorization model were also used to verify the contributions of different source components of BrC absorption at 365 nm. The results consistently demonstrate that the biomass burning and secondary formation contributes significantly to the overall absorption, followed by coal combustion and traffic emission.</p>

The aging process of ambient black carbon and brown carbon from biomass burning emission during MOYA-2017 aircraft campaign

2020 ◽  
Author(s):  
HuiHui Wu ◽  
Jonathan Taylor ◽  
Justin Langridge ◽  
Chenjie Yu ◽  
Paul Williams ◽  
...  
Keyword(s):  
Black Carbon ◽  
Biomass Burning ◽  
Aging Process ◽  
Atmospheric Dispersion ◽  
Chemical Properties ◽  
Carbonaceous Aerosol ◽  
Brown Carbon ◽  
Research Aircraft ◽  
Flaming Combustion ◽  
The Uk

<p>The biomass burning over West Africa during the dry season (December – February) is a globally significant source of trace gases and carbonaceous aerosol particles in the atmosphere. The MOYA-2017 (Methane Observations Yearly Assessments 2017) campaign were conducted using the UK FAAM Bae-146 airborne research aircraft, to investigate biomass burning emissions in this region. Research sorties were flown out of Senegal, with some flights directly over terrestrial fires and others sampling transported smokes over the Atlantic ocean.</p><p>The aircraft was equipped with a variety of aerosol-related instruments to measure submicron aerosol chemical properties (aerosol mass spectrometer, AMS and single-particle soot photometer, SP2) and absorption at different wavelengths (Photoacoustic spectrometer, PAS, measure at 405, 514 and 658 nm). In this study, we focus on the aging process of ambient black carbon (BC) and brown carbon (BrC) from biomass burning, in time scale from (<0.5) h to (9 – 15) h. The transport age of smokes was estimated using Met Office's Numerical Atmospheric-dispersion Modelling Environment (NAME).</p><p>The sampled smokes during MOYA-2017 were controlled by flaming-phase combustion. The enhancement ratios of BC with respect to CO ranged from 14 to 26 (ng m<sup>–3</sup> / ppbv) at sources. Our measurements show that count and mass median diameters of BC core size were relatively stable, which were around 106 and 190 nm respectively. Average BC coating thickness increased from (1.16 ± 0.03) to (1.71 ± 0.06) after approximately half-day transport. Average absorption angstrom exponents (AAE<sub>405-658</sub>) increased from (1.1 ± 0.1) to (1.8 ± 0.3), suggesting that BrC contributed little in the very freshly emitted aerosols (<0.5 h) and were formed during aging process. In order to investigate the importance of BrC in this area, we also attributed the measured aerosol absorption into BC and BrC separately. By linking AAE<sub>405-658</sub> with organic (OA) composition measured by the AMS, we found that the increasing AAE<sub>405-658</sub> is positively correlated with O/C ratio (oxygenation) of the OA. These data indicate that BrC in smokes controlled by flaming combustion is likely to be from the condensation of semi-volatile OA during cooling stage of smokes, and from the aged primary OA or secondary OA formation.</p>

scholarly journals Brown carbon absorption linked to organic mass tracers in biomass burning particles

2013 ◽  
Vol 13 (5) ◽  
pp. 2415-2422 ◽  
Author(s):  
D. A. Lack ◽  
R. Bahreini ◽  
J. M. Langridge ◽  
J. B. Gilman ◽  
A. M. Middlebrook
Keyword(s):  
Organic Matter ◽  
Black Carbon ◽  
Biomass Burning ◽  
Absorption Efficiency ◽  
Brown Carbon ◽  
Internal Mixing ◽  
Carbon Absorption ◽  
Mass Fractions ◽  
Biomass Burning Particles ◽  
532 Nm

Abstract. Traditional gas and particle phase chemical markers used to identify the presence of biomass burning (BB) emissions were measured for a large forest fire near Boulder, Colorado. Correlation of the organic matter mass spectroscopic m/z 60 with measured particle light absorption properties found no link at 532 nm, and a strong correlation at 404 nm. Non-black carbon absorption at 404 nm was well correlated to the ratio of the mass fractions of particulate organic matter (POM) that was m/z 60 (f60) to m/z 44 (f44). The f60 to f44 ratio did not fully explain the variability in non-BC absorption, due to contributions of brown carbon (BrC) absorption and absorption due to internal mixing of POM with black carbon (BC). The absorption Ångstrom exponent (ÅAbs) showed a good correlation to f60/f44; however the best correlation resulted from the mass absorption efficiency (MAE) of BrC at 404 nm (MAEPOM-404 nm) and f60/f44. This result indicates that the absorption of POM at low visible and UV wavelengths is linked to emissions of organic matter that contribute to the m/z 60 mass fragment, although they do not contribute to 532 nm absorption. m/z 60 is often attributed to levoglucosan and related compounds. The linear relationship between MAEPOM-404 nm and f60/f44 suggests that the strength of BrC absorption for this fire can be predicted by emissions of f60-related organic matter.

scholarly journals Characterization and source apportionment of atmospheric organic and elemental carbon during fall and winter of 2003 in Xi'an, China

2005 ◽  
Vol 5 (3) ◽  
pp. 3561-3593 ◽  
Author(s):  
J. J. Cao ◽  
J. C. Chow ◽  
S. C. Lee ◽  
Y. Li ◽  
S. W. Chen ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Diesel Exhaust ◽  
Coal Combustion ◽  
Elemental Carbon ◽  
Motor Vehicle ◽  
Principal Component ◽  
Total Carbon ◽  
Carbonaceous Aerosol ◽  
Vehicle Exhaust ◽  
Carbon Fraction

Abstract. Continuous observation of atmospheric organic and elemental carbon (OC, EC) were conducted at Xi'an during high pollution seasons from September 2003 to February 2004. PM2.5 samples were collected on pre-fired quartz-fiber filters with battery-powered mini-volume samplers every day and PM10 samples were collected every third days. Three types of source samples (i.e., coal-combustion, motor vehicle exhaust, and biomass burning) were also collected during ambient sampling period. Ambient and source samples were analyzed for OC and EC by thermal/optical reflectance (TOR) following the Interagency Monitoring of Protected Visual Environments (IMPROVE) protocol. The average PM2.5 OC concentrations in fall and winter were 34.1±18.0 µg m-3 and 61.9±33.2 µg m-3, respectively, while EC were 11.3±6.9 µg m-3 and 12.3±5.3 µg m-3, respectively. Most of OC and EC were associated with fine particle (PM2.5) mode. The OC and EC levels at Xi'an are higher than most urban cities in Asia. The OC and EC in fall were found to be strongly correlated (R2>0.9), with moderate correlation in winter (R2=0.66). The carbonaceous aerosol accounted for 48.8±10.1% of the PM2.5 during fall and 45.9±7.5% during winter. Average OC/EC ratio was 3.3 in fall and 5.1 in winter with individual OC/EC ratios constantly exceeding 2.0. Elevated OC/EC ratios were found during heating seasons with increased coal combustion. The contribution of secondary organic carbon was not significant during winter. The time series of OC and EC showed periodic variability. Traffic contributes 5 and 7 day peaks in the spectrum, precipitation appears as a 10 day periodicity and biomass burning can be identified as a 24 day periodicity. Total carbon (TC) was apportioned by absolute principal component analysis (APCA) using the 8 carbon fraction data (OC1, OC2, OC3, OC4, EC1, EC2, EC3, and OP [a pyrolyzed carbon fraction]). TC attributes 73% to gasoline exhaust, 23% to diesel exhaust, and 4% to biomass burning during fall. However, TC attributes 44% each to gasoline exhaust and coal burning, 9% to biomass burning, and 3% to diesel exhaust during winter.

Optical properties of atmospheric brown carbon (BrC) for photochemical and biomass burning-dominated aerosol regimes in India.

2020 ◽  
Author(s):  
Archita Rana ◽  
Supriya Dey ◽  
Sayantan Sarkar
Keyword(s):  
Optical Properties ◽  
Biomass Burning ◽  
Global Climate ◽  
Strong Association ◽  
Absorption Efficiency ◽  
Water Soluble ◽  
Tropospheric Chemistry ◽  
Gangetic Plain ◽  
Brown Carbon ◽  
Fluorescence Measurements

<p>Black and brown carbon (BC and BrC) are potent climate forcing agents with pronounced effects on global climate and tropospheric chemistry. Given the large heterogeneities in BC emission inventories from India and the paucity of studies on BrC characteristics, field-based measurements of BC and BrC sources and optical properties are essential to understand their impacts on regional climate. To address this issue, we report the first ground-based measurements of BC and BrC from a rural location in the highly polluted eastern Indo-Gangetic Plain (IGP) during May-November 2018 encompassing the photochemistry-dominated summer (May-June) and regional biomass burning (BB)-dominated post-monsoon (October-November) periods. A 7-wavelength Aethalometer was used for time-resolved measurements of BC mass and was supplemented by UV-Vis and fluorescence measurements of time-integrated (24 h) aqueous and organic BrC fractions, and measurements of OC, EC, WSOC, and ionic species.<br>The daily averaged BC increased 4 times during the BB regime (12.3 ± 3.9 μg m<sup>-3</sup>) as compared to summer (4.2 ± 0.8 μg m<sup>-3</sup>), while aqueous and organic BrC fractions demonstrated light absorption (babs_365) enhancements of 3-5 times during BB. For aqueous BrC, the averaged AE of 5.9-6.2 and a prominent fluorescence peak at ~420 nm suggested the presence of humic-like substances (HULIS), potentially from secondary photochemical formation during summer and primary emission during BB periods. Fluorescence and UV-Vis spectra also indicated the presence of nitroaromatic compounds, presumably from OH oxidation in summer and nighttime NO3- oxidation in the presence of enhanced NOx and precursor emission during BB. The latter was supported by the strong association between water-soluble organic carbon (WSOC; a proxy for aqueous BrC) and aerosol NO<sub>3</sub><sup>-</sup> (r=0.70, p<0.05). During BB, the fraction of water-insoluble (i.e., organic) BrC increased from 41% at 330 nm to 59 % at 550 nm while during the photochemistry-dominated summer period, the water-insoluble BrC fraction decreased from 73% at 400 nm to 41% at 530 nm, possibly due to photobleaching in the presence of OH. The BB-related BrC aerosol was also characterized by higher aromaticity and increased molecular weights of organic components as evidenced by mass absorption efficiency (MAE) ratios (MAE<sub>250</sub>/MAE<sub>365</sub>). Overall, this study established that BrC is a significant component of light-absorbing aerosol in the eastern IGP and that BrC optical properties may vary significantly in this region depending on the relative dominance of aerosol emissions and atmospheric processes.</p>

scholarly journals Brown carbon absorption linked to organic mass tracers in biomass burning particles

2012 ◽  
Vol 12 (11) ◽  
pp. 29129-29146
Author(s):  
D. A. Lack ◽  
R. Bahreni ◽  
J. M. Langridge ◽  
J. B. Gilman ◽  
A. M. Middlebrook
Keyword(s):  
Organic Matter ◽  
Biomass Burning ◽  
Absorption Efficiency ◽  
Brown Carbon ◽  
Internal Mixing ◽  
Mass Fractions ◽  
Biomass Burning Particles ◽  
The Impact ◽  
Related Compounds ◽  
532 Nm

Abstract. Traditional gas and particle phase chemical markers used to identify the presence of biomass burning (BB) emissions were measured for a large forest fire near Boulder, Colorado. Correlation of the mass spectroscopic marker of levoglucosan (m/z 60) with measured particle light absorption properties found no link at 532 nm, and a strong correlation at 404 nm. Non-black carbon (BC) absorption at 404 nm was well correlated to the ratio of the mass fractions of particulate organic matter (POM) that were m/z 60 (f60) to m/z 44 (f44). The f60 to f44 ratio did not fully explain the variability in non-BC absorption, due to contributions of brown carbon (BrC) absorption and absorption due to internal mixing of POM with BC. The absorption Ångstrom exponent (å) showed a good correlation to f60/f44; however the best correlation resulted from the mass absorption efficiency (MAE) of BrC at 404 nm (MAEPOM-404 nm) and f60/f44. This result indicates that the absorption of POM at low visible and UV wavelengths is primarily driven by emissions of levoglucosan (and related compounds), although they do not contribute to 532 nm absorption in this fire. The linear relationship between MAEPOM-404 nm and f60/f44 suggests that the impact of BrC can be predicted by emissions of f60-related organic matter.

scholarly journals Absorbing aerosol in the troposphere of the Western Arctic during the 2008 ARCTAS/ARCPAC airborne field campaigns

2011 ◽  
Vol 11 (15) ◽  
pp. 7561-7582 ◽  
Author(s):  
C. S. McNaughton ◽  
A. D. Clarke ◽  
S. Freitag ◽  
V. N. Kapustin ◽  
Y. Kondo ◽  
...  
Keyword(s):  
Black Carbon ◽  
Biomass Burning ◽  
Light Absorption ◽  
Carbonaceous Aerosol ◽  
Brown Carbon ◽  
Mass Absorption ◽  
Total Light ◽  
Western Arctic ◽  
Field Campaigns

Abstract. In the spring of 2008 NASA and NOAA funded the ARCTAS and ARCPAC field campaigns as contributions to POLARCAT, a core IPY activity. During the campaigns the NASA DC-8, P-3B and NOAA WP-3D aircraft conducted over 160 h of in-situ sampling between 0.1 and 12 km throughout the Western Arctic north of 55° N (i.e. Alaska to Greenland). All aircraft were equipped with multiple wavelength measurements of aerosol optics, trace gas and aerosol chemistry measurements, as well as direct measurements of the aerosol size distributions and black carbon mass. Late April of 2008 proved to be exceptional in terms of Asian biomass burning emissions transported to the Western Arctic. Though these smoke plumes account for only 11–14 % of the samples within the Western Arctic domain, they account for 42–47 % of the total burden of black carbon. Dust was also commonly observed but only contributes to 4–12 % and 3–8 % of total light absorption at 470 and 530 nm wavelengths above 6 km. Below 6 km, light absorption by carbonaceous aerosol derived from urban/industrial and biomass burning emissions account for 97–99 % of total light absorption by aerosol. Stratifying the data to reduce the influence of dust allows us to determine mass absorption efficiencies for black carbon of 11.2±0.8, 9.5±0.6 and 7.4±0.7 m2 g−1 at 470, 530 and 660 nm wavelengths. These estimates are consistent with 35–80 % enhancements in 530 nm absorption due to clear or slightly absorbing coatings of pure black carbon particulate. Assuming a 1/λ wavelength dependence for BC absorption, and assuming that refractory aerosol (420 °C, τ = 0.1 s) in low-dust samples is dominated by brown carbon, we derive mass absorption efficiencies for brown carbon of 0.83±0.15 and 0.27±0.08 m2 g−1 at 470 and 530 nm wavelengths. Estimates for the mass absorption efficiencies of Asian dust are 0.034 m2 g−1 and 0.017 m2 g−1. However the absorption efficiency estimates for dust are highly uncertain due to the limitations imposed by PSAP instrument noise. In-situ ARCTAS/ARCPAC measurements during the IPY provide valuable constraints for absorbing aerosol over the Western Arctic, species which are currently poorly simulated over a region that is critically under-sampled.

scholarly journals Carbonaceous aerosol AAE inferred from in-situ aerosol measurements at the Gosan ABC super site, and the implications for brown carbon aerosol

2012 ◽  
Vol 12 (14) ◽  
pp. 6173-6184 ◽  
Author(s):  
C. E. Chung ◽  
S.-W. Kim ◽  
M. Lee ◽  
S.-C. Yoon ◽  
S. Lee
Keyword(s):  
Absorption Coefficient ◽  
Biomass Burning ◽  
Mass Density ◽  
Carbonaceous Aerosol ◽  
Mass Ratio ◽  
Ambient Conditions ◽  
Absorption Data ◽  
Ambient Aerosols ◽  
Brown Carbon ◽  
Aerosol Absorption

Abstract. The Mass Absorption Cross section (MAC) and Absorption Ångström Exponent (AAE) have been commonly estimated for ambient aerosols but rarely for black carbon (BC) or organic aerosol (OA) alone in the ambient conditions. Here, we provide estimates of BC (and OA) MAC and AAE in East Asian outflow, by analyzing field data collected at the Gosan ABC super site. At this site, EC (and OC) carbon mass, the aerosol absorption coefficient at 7 wavelengths and PM mass density were continuously measured from October 2009 to June 2010. We remove the absorption data with significant dust influence using the mass ratio of PM10 to PM2.5. The remaining data shows an AAE of about 1.27, which we suggest represent the average carbonaceous aerosol (CA) AAE at Gosan. We find a positive correlation between the mass ratio of OC to EC and CA AAE, and successfully increase the correlation by filtering out data associated with weak absorption signal. After the filtering, absorption coefficient is regressed on OC and EC mass densities. BC and OA MACs are found to be 5.1 (3.8–6.1) and 1.4 (0.8–2.0) m2 g−1 at 520 nm respectively. From the estimated BC and OA MAC, we find that OA contributes about 45% to CA absorption at 520 nm. BC AAE is found to be 0.7–1.0, and is probably even lower considering the instrument bias. OA AAE is found to be 1.6–1.8. Compared with a previous estimate of OA MAC and AAE near biomass burning, our estimates at Gosan strongly suggest that the strongly-absorbing so-called brown carbon spheres are either unrelated to biomass burning or absent near the emission source.

scholarly journals Spatiotemporal distribution of light-absorbing carbon and its relationship to other atmospheric pollutants in Stockholm

2011 ◽  
Vol 11 (22) ◽  
pp. 11553-11567 ◽  
Author(s):  
P. Krecl ◽  
A. C. Targino ◽  
C. Johansson
Keyword(s):  
Exhaust Emissions ◽  
Atmospheric Pollutants ◽  
Spatiotemporal Variability ◽  
Rural Site ◽  
Strong Increase ◽  
Population Exposure ◽  
Emission Sources ◽  
Vehicle Exhaust ◽  
Urban Background ◽  
Urban Sites

Abstract. Carbon-containing particles have deleterious effects on both Earth's climate and human health. In Europe, the main sources of light-absorbing carbon (LAC) emissions are the transport (67%) and residential (25%) sectors. Information on the spatiotemporal variability of LAC particles in urban areas is relevant for air quality management and to better diagnose the population exposure to these particles. This study reports on results of an intensive field campaign conducted at four sites (two kerbside stations, one urban background site and a rural station) in Stockholm, Sweden, during the spring 2006. Light-absorbing carbon mass (MLAC) concentrations were measured with custom-built Particle Soot Absorption Photometers (PSAP). The spatiotemporal variability of MLAC concentrations was explored by examining correlation coefficients (R), coefficients of divergence (COD), and diurnal patterns at all sites. Simultaneous measurements of NOx, PM10, PM2.5, and meteorological variables were also carried out at the same locations to help characterize the LAC emission sources. Hourly mean (± standard deviation) MLAC concentrations ranged from 0.36±0.50 at the rural site to 5.39±3.60 μg m−3 at the street canyon site. Concentrations of LAC between urban sites were poorly correlated even for daily averages (R<0.70), combined with highly heterogeneously distributed concentrations (COD>0.30) even at spatial scales of few kilometers. This high variability is connected to the distribution of emission sources and processes contributing to the LAC fraction at these sites. At urban sites, MLAC tracked NOx levels and traffic density well and mean MLAC/PM2.5 ratios were larger (26–38%) than at the background sites (4–10%). The results suggest that vehicle exhaust emissions are the main responsible for the high MLAC concentrations found at the urban locations whereas long-range transport (LRT) episodes of combustion-derived particles can generate a strong increase of levels at background sites. To decrease pollution levels at kerbside and urban background locations in Stockholm, we recommend abatement strategies that target reductions of vehicle exhaust emissions, which are the main contributors to MLAC and NOx concentrations.

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