Polycyclic Aromatic Carbon: A Key Fraction Determining the Light Absorption Properties of Methanol-Soluble Brown Carbon of Open Biomass Burning Aerosols

2021 ◽  
Author(s):  
Yue Sun ◽  
Jiao Tang ◽  
Yangzhi Mo ◽  
Xiaofei Geng ◽  
Guangcai Zhong ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Light Absorption ◽  
Absorption Properties ◽  
Brown Carbon ◽  
Aromatic Carbon ◽  
Polycyclic Aromatic

scholarly journals A dominant contribution to light absorption by methanol-insoluble brown carbon produced in the combustion of biomass fuels typically consumed in wildland fires in the United States

2022 ◽  
Author(s):  
Khairallah Atwi ◽  
Charles Perrie ◽  
Zezhen Cheng ◽  
Omar El Hajj ◽  
Rawad Saleh
Keyword(s):  
United States ◽  
Solvent Extraction ◽  
Light Absorption ◽  
The United States ◽  
Extraction Methods ◽  
Wildland Fires ◽  
Dominant Contribution ◽  
Biomass Fuels ◽  
Absorption Properties ◽  
Brown Carbon

The light-absorption properties of brown carbon (BrC) are often estimated using offline, solvent-extraction methods. However, recent studies have found evidence of insoluble species of BrC which are unaccounted for in...

Light absorption properties of elemental carbon (EC) and water-soluble brown carbon (WS–BrC) in the Kathmandu Valley, Nepal: A 5-year study

2020 ◽  
Vol 261 ◽  
pp. 114239 ◽  
Author(s):  
Pengfei Chen ◽  
Shichang Kang ◽  
Lekhendra Tripathee ◽  
Kirpa Ram ◽  
Maheswar Rupakheti ◽  
...  
Keyword(s):  
Light Absorption ◽  
Elemental Carbon ◽  
Water Soluble ◽  
Kathmandu Valley ◽  
Absorption Properties ◽  
Brown Carbon

scholarly journals Dynamic light absorption of biomass-burning organic carbon photochemically aged under natural sunlight

2014 ◽  
Vol 14 (3) ◽  
pp. 1517-1525 ◽  
Author(s):  
M. Zhong ◽  
M. Jang
Keyword(s):  
Organic Carbon ◽  
Biomass Burning ◽  
Light Absorption ◽  
Dynamic Change ◽  
Wood Smoke ◽  
Integrating Sphere ◽  
Natural Sunlight ◽  
Wood Burning ◽  
Polycyclic Aromatic ◽  
Uv Visible

Abstract. Wood-burning aerosol produced under smoldering conditions was photochemically aged with different relative humidity (RH) and NOx conditions using a 104 m3 dual outdoor chamber under natural sunlight. Light absorption of organic carbon (OC) was measured over the course of photooxidation using a UV–visible spectrometer connected to an integrating sphere. At high RH, the color decayed rapidly. NOx slightly prolonged the color of wood smoke, suggesting that NOx promotes the formation of chromophores via secondary processes. Overall, the mass absorption cross section (integrated between 280 and 600 nm) of OC increased by 11–54% (except high RH) in the morning and then gradually decreased by 19–68% in the afternoon. This dynamic change in light absorption of wood-burning OC can be explained by two mechanisms: chromophore formation and sunlight bleaching. To investigate the effect of chemical transformation on light absorption, wood smoke particles were characterized using various spectrometers. The intensity of fluorescence, which is mainly related to polycyclic aromatic hydrocarbons (PAHs), rapidly decreased with time, indicating the potential bleaching of PAHs. A decline of levoglucosan concentrations evinced the change of primary organic aerosol with time. The aerosol water content measured by Fourier transform infrared spectroscopy showed that wood-burning aerosol became less hygroscopic as photooxidation proceeded. A similar trend in light absorption changes has been observed in ambient smoke aerosol originating from the 2012 County Line wildfire in Florida. We conclude that the biomass-burning OC becomes less light absorbing after 8–9 h sunlight exposure compared to fresh wood-burning OC.

Light absorption properties of brown carbon over the southeastern Tibetan Plateau

2018 ◽  
Vol 625 ◽  
pp. 246-251 ◽  
Author(s):  
Chong-Shu Zhu ◽  
Jun-Ji Cao ◽  
Ru-Jin Huang ◽  
Zhen-Xing Shen ◽  
Qi-Yuan Wang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Light Absorption ◽  
Absorption Properties ◽  
Brown Carbon ◽  
Southeastern Tibetan Plateau

Evolution of the light-absorption properties of combustion brown carbon aerosols following reaction with nitrate radicals

2020 ◽  
Vol 54 (7) ◽  
pp. 849-863 ◽  
Author(s):  
Zezhen Cheng ◽  
Khairallah M. Atwi ◽  
Zhenhong Yu ◽  
Anita Avery ◽  
Edward C. Fortner ◽  
...  
Keyword(s):  
Light Absorption ◽  
Absorption Properties ◽  
Brown Carbon ◽  
Nitrate Radicals ◽  
Carbon Aerosols

scholarly journals The characteristics of atmospheric brown carbon in Xi'an, inland China: sources, size distributions and optical properties

2020 ◽  
Vol 20 (4) ◽  
pp. 2017-2030 ◽  
Author(s):  
Can Wu ◽  
Gehui Wang ◽  
Jin Li ◽  
Jianjun Li ◽  
Cong Cao ◽  
...  
Keyword(s):  
Optical Properties ◽  
Biomass Burning ◽  
Isotope Composition ◽  
Stable Carbon Isotope ◽  
Urban Atmosphere ◽  
Semiarid Region ◽  
Chemical Compositions ◽  
Brown Carbon ◽  
Polycyclic Aromatic ◽  
Fine Mode

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.

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

&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;

Light absorption properties, chromophore composition and sources of brown carbon aerosol in Xi’an, Northwest China

2020 ◽  
Author(s):  
Ru-Jin Huang ◽  
Wei Yuan ◽  
Lu Yang ◽  
Jie Guo ◽  
Jing Duan ◽  
...  
Keyword(s):  
Light Absorption ◽  
Coal Combustion ◽  
Radiative Forcing ◽  
Northwest China ◽  
Absorption Efficiency ◽  
Vehicular Emissions ◽  
Absorption Properties ◽  
Seasonal Differences ◽  
Brown Carbon ◽  
The Impact

&lt;p&gt;The impact of brown carbon aerosol (BrC) on the Earth&amp;#8217;s radiative forcing balance has been widely recognized but remains uncertain, mainly because the relationships among BrC sources, chromophores, and optical properties of aerosol are poorly understood (Feng et al., 2013; Laskin et al., 2015). In this work, the light absorption properties and chromophore composition of BrC were investigated for samples collected in Xi&amp;#8217;an, Northwest China from 2015 to 2016. Both absorption &amp;#197;ngstro&amp;#776;m exponent and mass absorption efficiency show distinct seasonal differences, which could be attributed to the differences in sources and chromophore composition of BrC. Three groups of light-absorbing organics were found to be important BrC chromophores, including those show multiple absorption peaks at wavelength &gt; 350 nm (12 polycyclic aromatic hydrocarbons and their derivatives) and those show single absorption peak at wavelength &lt; 350 nm (10 nitrophenols and nitrosalicylic acids and 3 methoxyphenols). These measured BrC chromophores show distinct seasonal differences and contribute on average about 1.1% and 3.3% of light absorption of methanol-soluble BrC at 365 nm in summer and winter, respectively, about 7 and 5 times higher than the corresponding mass fractions in total organic carbon. The sources of BrC were resolved by positive matrix factorization (PMF) using these chromophores instead of commonly used non-light absorbing organic markers as model inputs. Our results show that in spring vehicular emissions and secondary formation are major sources of BrC (~70%), in fall coal combustion and vehicular emissions are major sources (~70%), in winter biomass burning and coal combustion become major sources (~80%), while in summer secondary BrC dominates (~60%).&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;References:&lt;/p&gt;&lt;p&gt;Feng, Y., V. Ramanathan, and V. R. Kotamarthi: Brown carbon: A significant atmospheric absorber of solar radiation?, Atmos. Chem. Phys., 13, 8607-8621, doi:10.5194/acp-13-8607-2013, 2013.&lt;/p&gt;&lt;p&gt;Laskin, A., J. Laskin, and S. A. Nizkorodov: Chemistry of atmospheric brown carbon, Chem. Rev., 115, 4335-4382, doi:10.1021/cr5006167, 2015.&lt;/p&gt;

scholarly journals Light absorption of brown carbon aerosol in the PRD region of China

2016 ◽  
Vol 16 (3) ◽  
pp. 1433-1443 ◽  
Author(s):  
J.-F. Yuan ◽  
X.-F. Huang ◽  
L.-M. Cao ◽  
J. Cui ◽  
Q. Zhu ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Light Absorption ◽  
Radiative Forcing ◽  
Measurement Data ◽  
Theoretical Assumption ◽  
Ambient Aerosols ◽  
Brown Carbon ◽  
Mass Spectrometers ◽  
Rural Environments ◽  
The Pearl River

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.

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