Chromophoric Fingerprinting of Brown Carbon from Residential Biomass Burning

Author(s):  
Ru-Jin Huang ◽  
Lu Yang ◽  
Jincan Shen ◽  
Wei Yuan ◽  
Yuquan Gong ◽  
...  
Keyword(s):  
2019 ◽  
Vol 19 (17) ◽  
pp. 11213-11233 ◽  
Author(s):  
Xiaoyan Liu ◽  
Yan-Lin Zhang ◽  
Yiran Peng ◽  
Lulu Xu ◽  
Chunmao Zhu ◽  
...  

Abstract. Biomass burning can significantly impact the chemical and optical properties of carbonaceous aerosols. Here, the biomass burning impacts were studied during wintertime in a megacity of Nanjing, eastern China. The high abundance of biomass burning tracers such as levoglucosan (lev), mannosan (man), galactosan (gal) and non-sea-salt potassium (nss-K+) was found during the studied period with the concentration ranges of 22.4–1476 ng m−3, 2.1–56.2 ng m−3, 1.4–32.2 ng m−3 and 0.2–3.8 µg m−3, respectively. The significant contribution of biomass burning to water-soluble organic carbon (WSOC; 22.3±9.9 %) and organic carbon (OC; 20.9±9.3 %) was observed in this study. Backward air mass origin analysis, potential emission sensitivity of elemental carbon (EC) and MODIS fire spot information indicated that the elevations of the carbonaceous aerosols were due to the transported biomass-burning aerosols from southeastern China. The characteristic mass ratio maps of lev∕man and lev∕nss-K+ suggested that the biomass fuels were mainly crop residuals. Furthermore, the strong correlation (p < 0.01) between biomass burning tracers (such as lev) and light absorption coefficient (babs) for water-soluble brown carbon (BrC) revealed that biomass burning emissions played a significant role in the light-absorption properties of carbonaceous aerosols. The solar energy absorption due to water-soluble brown carbon and EC was estimated by a calculation based on measured light-absorbing parameters and a simulation based on a radiative transfer model (RRTMG_SW). The solar energy absorption of water-soluble BrC in short wavelengths (300–400 nm) was 0.8±0.4 (0.2–2.3) W m−2 (figures in parentheses represent the variation range of each parameter) from the calculation and 1.2±0.5 (0.3–1.9) W m−2 from the RRTMG_SW model. The absorption capacity of water-soluble BrC accounted for about 20 %–30 % of the total absorption of EC aerosols. The solar energy absorption of water-soluble BrC due to biomass burning was estimated as 0.2±0.1 (0.0–0.9) W m−2, considering the biomass burning contribution to carbonaceous aerosols. Potential source contribution function model simulations showed that the solar energy absorption induced by water-soluble BrC and EC aerosols was mostly due to the regionally transported carbonaceous aerosols from source regions such as southeastern China. Our results illustrate the importance of the absorbing water-soluble brown carbon aerosols in trapping additional solar energy in the low-level atmosphere, heating the surface and inhibiting the energy from escaping the atmosphere.


2020 ◽  
Vol 20 (4) ◽  
pp. 2017-2030 ◽  
Author(s):  
Can Wu ◽  
Gehui Wang ◽  
Jin Li ◽  
Jianjun Li ◽  
Cong Cao ◽  
...  

Abstract. To investigate the characteristics of atmospheric brown carbon (BrC) in the semiarid region of East Asia, PM2.5 and size-resolved particles in the urban atmosphere of Xi'an, inland China, during the winter and summer of 2017 were collected and analyzed for optical properties and chemical compositions. Methanol extracts (MeOH extracts) were more light-absorbing than water extracts (H2O extracts) in the optical wavelength of 300–600 nm and well correlated with nitrophenols, polycyclic aromatic hydrocarbons (PAHs) and oxygenated PAHs (r > 0.78). The light absorptions (absλ=365 nm) of H2O extracts and MeOH extracts in winter were 28±16 and 49±32 M m−1, respectively, which are about 10 times higher than those in summer, mainly due to the enhanced emissions from biomass burning for house heating. Water-extracted BrC predominately occurred in the fine mode (< 2.1 µm) during winter and summer, accounting for 81 % and 65 % of the total absorption of BrC, respectively. The light absorption and stable carbon isotope composition measurements showed an increasing ratio of absλ=365 nm-MeOH to absλ=550 nm-EC along with an enrichment of 13C in PM2.5 during the haze development, indicating an accumulation of secondarily formed BrC (e.g., nitrophenols) in the aerosol aging process. Positive matrix factorization (PMF) analysis showed that biomass burning, fossil fuel combustion, secondary formation, and fugitive dust are the major sources of BrC in the city, accounting for 55 %, 19 %, 16 %, and 10 % of the total BrC of PM2.5, respectively.


2016 ◽  
Vol 16 (15) ◽  
pp. 9549-9561 ◽  
Author(s):  
Rudra P. Pokhrel ◽  
Nick L. Wagner ◽  
Justin M. Langridge ◽  
Daniel A. Lack ◽  
Thilina Jayarathne ◽  
...  

Abstract. Single-scattering albedo (SSA) and absorption Ångström exponent (AAE) are two critical parameters in determining the impact of absorbing aerosol on the Earth's radiative balance. Aerosol emitted by biomass burning represent a significant fraction of absorbing aerosol globally, but it remains difficult to accurately predict SSA and AAE for biomass burning aerosol. Black carbon (BC), brown carbon (BrC), and non-absorbing coatings all make substantial contributions to the absorption coefficient of biomass burning aerosol. SSA and AAE cannot be directly predicted based on fuel type because they depend strongly on burn conditions. It has been suggested that SSA can be effectively parameterized via the modified combustion efficiency (MCE) of a biomass burning event and that this would be useful because emission factors for CO and CO2, from which MCE can be calculated, are available for a large number of fuels. Here we demonstrate, with data from the FLAME-4 experiment, that for a wide variety of globally relevant biomass fuels, over a range of combustion conditions, parameterizations of SSA and AAE based on the elemental carbon (EC) to organic carbon (OC) mass ratio are quantitatively superior to parameterizations based on MCE. We show that the EC ∕ OC ratio and the ratio of EC ∕ (EC + OC) both have significantly better correlations with SSA than MCE. Furthermore, the relationship of EC ∕ (EC + OC) with SSA is linear. These improved parameterizations are significant because, similar to MCE, emission factors for EC (or black carbon) and OC are available for a wide range of biomass fuels. Fitting SSA with MCE yields correlation coefficients (Pearson's r) of  ∼  0.65 at the visible wavelengths of 405, 532, and 660 nm while fitting SSA with EC / OC or EC / (EC + OC) yields a Pearson's r of 0.94–0.97 at these same wavelengths. The strong correlation coefficient at 405 nm (r =  0.97) suggests that parameterizations based on EC / OC or EC / (EC + OC) have good predictive capabilities even for fuels in which brown carbon absorption is significant. Notably, these parameterizations are effective for emissions from Indonesian peat, which have very little black carbon but significant brown carbon (SSA  =  0.990 ± 0.001 at 532 and 660 nm, SSA  =  0.937 ± 0.011 at 405 nm). Finally, we demonstrate that our parameterization based on EC / (EC + OC) accurately predicts SSA during the first few hours of plume aging with data from Yokelson et al. (2009) gathered during a biomass burning event in the Yucatán Peninsula of Mexico.


2020 ◽  
Author(s):  
Ting Wang ◽  
Rujin Huang ◽  
Lu Yang ◽  
Wei Yuan ◽  
Yuquan Gong

&lt;p&gt;Atmospheric brown carbon (BrC) has significant impact on Earth&amp;#8217;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&amp;#8722;visible (UV&amp;#8722;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.&lt;/p&gt;


2020 ◽  
Author(s):  
HuiHui Wu ◽  
Jonathan Taylor ◽  
Justin Langridge ◽  
Chenjie Yu ◽  
Paul Williams ◽  
...  

&lt;p&gt;The biomass burning over West Africa during the dry season (December &amp;#8211; 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.&lt;/p&gt;&lt;p&gt;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 (&lt;0.5) h to (9 &amp;#8211; 15) h. The transport age of smokes was estimated using Met Office's Numerical Atmospheric-dispersion Modelling Environment (NAME).&lt;/p&gt;&lt;p&gt;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&lt;sup&gt;&amp;#8211;3&lt;/sup&gt; / 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 &amp;#177; 0.03) to (1.71 &amp;#177; 0.06) after approximately half-day transport. Average absorption angstrom exponents (AAE&lt;sub&gt;405-658&lt;/sub&gt;) increased from (1.1 &amp;#177; 0.1) to (1.8 &amp;#177; 0.3), suggesting that BrC contributed little in the very freshly emitted aerosols (&lt;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&lt;sub&gt;405-658&lt;/sub&gt; with organic (OA) composition measured by the AMS, we found that the increasing AAE&lt;sub&gt;405-658&lt;/sub&gt; 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.&lt;/p&gt;


2016 ◽  
Vol 50 (21) ◽  
pp. 11815-11824 ◽  
Author(s):  
Peng Lin ◽  
Paige K. Aiona ◽  
Ying Li ◽  
Manabu Shiraiwa ◽  
Julia Laskin ◽  
...  

2016 ◽  
Vol 16 (3) ◽  
pp. 1433-1443 ◽  
Author(s):  
J.-F. Yuan ◽  
X.-F. Huang ◽  
L.-M. Cao ◽  
J. Cui ◽  
Q. Zhu ◽  
...  

Abstract. The strong spectral dependence of light absorption of brown carbon (BrC) aerosol is regarded to influence aerosol's radiative forcing significantly. The Absorption Angstrom Exponent (AAE) method has been widely used in previous studies to attribute light absorption of BrC at shorter wavelengths for ambient aerosols, with a theoretical assumption that the AAE of "pure" black carbon (BC) aerosol equals to 1.0. In this study, the AAE method was applied to both urban and rural environments in the Pearl River Delta (PRD) region of China, with an improvement of constraining the realistic AAE of "pure" BC through statistical analysis of on-line measurement data. A three-wavelength photo-acoustic soot spectrometer (PASS-3) and aerosol mass spectrometers (AMS) were used to explore the relationship between the measured AAE and the relative abundance of organic aerosol to BC. The regression and extrapolation analysis revealed that more realistic AAE values for "pure" BC aerosol (AAEBC) were 0.86, 0.82, and 1.02 between 405 and 781 nm, and 0.70, 0.71, and 0.86 between 532 and 781 nm, in the campaigns of urbanwinter, urbanfall, and ruralfall, respectively. Roadway tunnel experiments were conducted and the results further confirmed the representativeness of the obtained AAEBC values for the urban environment. Finally, the average light absorption contributions of BrC (&amp;pm; relative uncertainties) at 405 nm were quantified to be 11.7 % (&amp;pm;5 %), 6.3 % (&amp;pm;4 %), and 12.1 % (&amp;pm;7 %) in the campaigns of urbanwinter, urbanfall, and ruralfall, respectively, and those at 532 nm were 10.0 % (&amp;pm;2 %), 4.1 % (&amp;pm;3 %), and 5.5 % (&amp;pm;5 %), respectively. The relatively higher BrC absorption contribution at 405 nm in the ruralfall campaign could be reasonably attributed to the biomass burning events nearby, which was then directly supported by the biomass burning simulation experiments performed in this study. This paper indicates that the BrC contribution to total aerosol light absorption at shorter wavelengths is not negligible in the highly urbanized and industrialized PRD region.


2017 ◽  
Vol 51 (20) ◽  
pp. 11561-11570 ◽  
Author(s):  
Peng Lin ◽  
Nir Bluvshtein ◽  
Yinon Rudich ◽  
Sergey A. Nizkorodov ◽  
Julia Laskin ◽  
...  

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