Light absorption properties and potential sources of particulate brown carbon in the Pearl River Delta region of China
<p>Brown carbon (BrC) is a special type of organic aerosol (OA), capable of absorbing solar radiation from near-ultraviolet (UV) to visible wavelengths, which may lead to an increased aerosol radiative effect in the atmosphere. While high concentrations of OAs have been observed in the Pearl R...
| Main Authors: | , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2019-09-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/19/11669/2019/acp-19-11669-2019.pdf |
| _version_ | 1818986068266975232 |
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| author | Z. Li Z. Li Z. Li H. Tan H. Tan J. Zheng L. Liu L. Liu Y. Qin Y. Qin N. Wang F. Li Y. Li M. Cai Y. Ma C. K. Chan |
| author_facet | Z. Li Z. Li Z. Li H. Tan H. Tan J. Zheng L. Liu L. Liu Y. Qin Y. Qin N. Wang F. Li Y. Li M. Cai Y. Ma C. K. Chan |
| author_sort | Z. Li |
| collection | DOAJ |
| description | <p>Brown carbon (BrC) is a special type of organic aerosol (OA), capable of
absorbing solar radiation from near-ultraviolet (UV) to visible wavelengths,
which may lead to an increased aerosol radiative effect in the atmosphere.
While high concentrations of OAs have been observed in the Pearl River Delta
(PRD) region of China, the optical properties and corresponding radiative
forcing of BrC in the PRD are still not well understood. In this work, we
conducted a set of comprehensive measurements of atmospheric particulate
matter from 29 November 2014 to 2 January 2015 to investigate aerosol
compositions, optical properties, source origins, and radiative forcing
effects at a suburban station in Guangzhou. The particle absorption
Ångström exponent (AAE) was deduced and utilized to distinguish
light absorption by BrC from that by black carbon (BC). The results showed
that the average absorption contributions of BrC were <span class="inline-formula">34.1±8.0</span> % at
370 nm, <span class="inline-formula">23.7±7.3</span> % at 470 nm, <span class="inline-formula">16.0±6.7</span> % at 520 nm,
<span class="inline-formula">13.0±5.4</span> % at 590 nm, and <span class="inline-formula">8.7±4.3</span> % at 660 nm. A
sensitivity analysis of the evaluation of the absorption Ångström
exponent of BC (AAE<span class="inline-formula"><sub>BC</sub>)</span> was conducted based on the Mie theory
calculation assuming that the BC-containing aerosol was mixed with the
core–shell and external configurations. The corresponding uncertainty in
AAE<span class="inline-formula"><sub>BC</sub></span> was acquired. We found that variations in the imaginary
refractive index (RI) of the BC core can significantly affect the estimation
of AAE<span class="inline-formula"><sub>BC</sub></span>. However, AAE<span class="inline-formula"><sub>BC</sub></span> was relatively less sensitive to the real
part of the RI of the BC core and was least sensitive to the real part of
the RI of the non-light-absorbing shell. BrC absorption was closely related
to aerosol potassium cation content (<span class="inline-formula">K<sup>+</sup></span>), a common tracer of biomass
burning emissions, which was most likely associated with straw burning in
the rural area of the western PRD. Diurnal variation in BrC absorption
revealed that primary organic aerosols had a larger BrC absorption capacity
than secondary organic aerosols (SOAs). Radiative transfer simulations
showed that BrC absorption may cause <span class="inline-formula">2.3±1.8</span> W m<span class="inline-formula"><sup>−2</sup></span> radiative
forcing at the top of the atmosphere (TOA) and contribute to <span class="inline-formula">15.8±4.4</span> % of the aerosol warming effect. A chart was constructed to
conveniently assess the BrC radiative forcing efficiency in the studied area
with reference to certain aerosol single-scattering albedo (SSA) and BrC
absorption contributions at various wavelengths. Evidently, the BrC
radiative forcing efficiency was higher at shorter wavelengths.</p> |
| first_indexed | 2024-12-20T18:44:55Z |
| format | Article |
| id | doaj.art-80f6be5dea04432cbd531e39d042bd3a |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-12-20T18:44:55Z |
| publishDate | 2019-09-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-80f6be5dea04432cbd531e39d042bd3a2022-12-21T19:29:44ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242019-09-0119116691168510.5194/acp-19-11669-2019Light absorption properties and potential sources of particulate brown carbon in the Pearl River Delta region of ChinaZ. Li0Z. Li1Z. Li2H. Tan3H. Tan4J. Zheng5L. Liu6L. Liu7Y. Qin8Y. Qin9N. Wang10F. Li11Y. Li12M. Cai13Y. Ma14C. K. Chan15Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science and Technology, Nanjing, ChinaKey Laboratory of Regional Numerical Weather Prediction, Institute of Tropical and Marine Meteorology, China Meteorological Administration, Guangzhou, ChinaNow at Emergency Early Warning Release and Weather Modification Center of Guangdong, Guangzhou 510080, ChinaKey Laboratory of Regional Numerical Weather Prediction, Institute of Tropical and Marine Meteorology, China Meteorological Administration, Guangzhou, ChinaFoshan Meteorological Service of Guangdong, Foshan 528010, Guangdong, ChinaCollaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science and Technology, Nanjing, ChinaKey Laboratory of Regional Numerical Weather Prediction, Institute of Tropical and Marine Meteorology, China Meteorological Administration, Guangzhou, ChinaDepartment of Atmospheric Science, Sun yat-sen University, Guangzhou, ChinaSchool of Energy and Environment, City University of Hong Kong SAR, Hong Kong, ChinaNow at School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USAKey Laboratory of Regional Numerical Weather Prediction, Institute of Tropical and Marine Meteorology, China Meteorological Administration, Guangzhou, ChinaKey Laboratory of Regional Numerical Weather Prediction, Institute of Tropical and Marine Meteorology, China Meteorological Administration, Guangzhou, ChinaDepartment of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau SAR, ChinaDepartment of Atmospheric Science, Sun yat-sen University, Guangzhou, ChinaCollaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science and Technology, Nanjing, ChinaSchool of Energy and Environment, City University of Hong Kong SAR, Hong Kong, China<p>Brown carbon (BrC) is a special type of organic aerosol (OA), capable of absorbing solar radiation from near-ultraviolet (UV) to visible wavelengths, which may lead to an increased aerosol radiative effect in the atmosphere. While high concentrations of OAs have been observed in the Pearl River Delta (PRD) region of China, the optical properties and corresponding radiative forcing of BrC in the PRD are still not well understood. In this work, we conducted a set of comprehensive measurements of atmospheric particulate matter from 29 November 2014 to 2 January 2015 to investigate aerosol compositions, optical properties, source origins, and radiative forcing effects at a suburban station in Guangzhou. The particle absorption Ångström exponent (AAE) was deduced and utilized to distinguish light absorption by BrC from that by black carbon (BC). The results showed that the average absorption contributions of BrC were <span class="inline-formula">34.1±8.0</span> % at 370 nm, <span class="inline-formula">23.7±7.3</span> % at 470 nm, <span class="inline-formula">16.0±6.7</span> % at 520 nm, <span class="inline-formula">13.0±5.4</span> % at 590 nm, and <span class="inline-formula">8.7±4.3</span> % at 660 nm. A sensitivity analysis of the evaluation of the absorption Ångström exponent of BC (AAE<span class="inline-formula"><sub>BC</sub>)</span> was conducted based on the Mie theory calculation assuming that the BC-containing aerosol was mixed with the core–shell and external configurations. The corresponding uncertainty in AAE<span class="inline-formula"><sub>BC</sub></span> was acquired. We found that variations in the imaginary refractive index (RI) of the BC core can significantly affect the estimation of AAE<span class="inline-formula"><sub>BC</sub></span>. However, AAE<span class="inline-formula"><sub>BC</sub></span> was relatively less sensitive to the real part of the RI of the BC core and was least sensitive to the real part of the RI of the non-light-absorbing shell. BrC absorption was closely related to aerosol potassium cation content (<span class="inline-formula">K<sup>+</sup></span>), a common tracer of biomass burning emissions, which was most likely associated with straw burning in the rural area of the western PRD. Diurnal variation in BrC absorption revealed that primary organic aerosols had a larger BrC absorption capacity than secondary organic aerosols (SOAs). Radiative transfer simulations showed that BrC absorption may cause <span class="inline-formula">2.3±1.8</span> W m<span class="inline-formula"><sup>−2</sup></span> radiative forcing at the top of the atmosphere (TOA) and contribute to <span class="inline-formula">15.8±4.4</span> % of the aerosol warming effect. A chart was constructed to conveniently assess the BrC radiative forcing efficiency in the studied area with reference to certain aerosol single-scattering albedo (SSA) and BrC absorption contributions at various wavelengths. Evidently, the BrC radiative forcing efficiency was higher at shorter wavelengths.</p>https://www.atmos-chem-phys.net/19/11669/2019/acp-19-11669-2019.pdf |
| spellingShingle | Z. Li Z. Li Z. Li H. Tan H. Tan J. Zheng L. Liu L. Liu Y. Qin Y. Qin N. Wang F. Li Y. Li M. Cai Y. Ma C. K. Chan Light absorption properties and potential sources of particulate brown carbon in the Pearl River Delta region of China Atmospheric Chemistry and Physics |
| title | Light absorption properties and potential sources of particulate brown carbon in the Pearl River Delta region of China |
| title_full | Light absorption properties and potential sources of particulate brown carbon in the Pearl River Delta region of China |
| title_fullStr | Light absorption properties and potential sources of particulate brown carbon in the Pearl River Delta region of China |
| title_full_unstemmed | Light absorption properties and potential sources of particulate brown carbon in the Pearl River Delta region of China |
| title_short | Light absorption properties and potential sources of particulate brown carbon in the Pearl River Delta region of China |
| title_sort | light absorption properties and potential sources of particulate brown carbon in the pearl river delta region of china |
| url | https://www.atmos-chem-phys.net/19/11669/2019/acp-19-11669-2019.pdf |
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