A one-year study on black carbon in urban Beijing: Concentrations, sources and implications on visibility

Li, Wenguang; Liu, Xingang; Duan, Fengkui; Yu, Qian; An, Junling

doi:10.1016/j.apr.2021.101307

Cited by 7 publications

(5 citation statements)

References 56 publications

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“…In particular, σ ab for PM 1 and PM 10 decreased even up to 63 % and 67 % in the summer from 2018 to 2021. Traffic is a relatively stable source of absorption aerosols in summer (W. Li et al, 2022). The largest deduction of σ ab was in summer and could be related to more strict vehicle emission standards (Zhang et al, 2019).…”

Section: Temporal Variation In Aerosol Optical Propertiesmentioning

confidence: 99%

“…During summer, the average AAE was generally close to 1, which suggested that BC from traffic emissions was the major component of light-absorbing aerosols. W. Li et al (2022) found that the percentage of liquid fuel (traffic) contributing to the total BC was 86.8 % in summer in Beijing. The highest AAE suggested that BrC contributed to light absorption strongest in winter, which is due to enhanced emissions from biomass burning and coal combustion in winter .…”

Section: Temporal Variation In Aerosol Optical Propertiesmentioning

confidence: 99%

“…Previous studies found that SSA values range from slightly less than 0.8 to almost purely scattering particles with SSA close to 1 at locations worldwide Pandolfi et al, 2018), and higher SSA values indicate a tendency towards a cooling effect (J. Li et al, 2022). b describes how much aerosol particles scatter radiation in the backward hemisphere compared with the total scattering, which is a crucial variable for aerosol radiative forcing efficiency (RFE) calculations (Andrews et al, 2011;Sheridan and Ogren, 1999;Luoma et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Measurement report: Rapid decline of aerosol absorption coefficient and aerosol optical property effects on radiative forcing in an urban area of Beijing from 2018 to 2021

Sun

Xia

et al. 2023

Atmos. Chem. Phys.

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Abstract. Reliable observations of aerosol optical properties are crucial for quantifying the radiative forcing of climate. The simultaneous measurements of aerosol optical properties at three wavelengths for PM1 and PM10 were conducted in urban Beijing from March 2018 to February 2022. The aerosol absorption coefficient (σab) at 550 nm of PM10 and PM1 decreased by 55.0 % and 53.5 % from 2018 to 2021. The significant reduction in σab may be related to reduced primary emissions caused by effective air pollution control measures. PM2.5 mass concentration decreased by 34.4 % from 2018 to 2021. Single scattering albedo (SSA) increased from 0.89±0.04 for PM10 (0.87±0.05 for PM1) in 2018 to 0.93±0.03 for PM10 (0.91±0.04 for PM1) in 2021. Increasing SSA and decreasing PM2.5 mass concentration suggest that the fraction of absorbing aerosols decreased with improved air quality due to pollution control measures being taken. The annual average submicron absorption ratio (Rab) increased from 86.1 % in 2018 to 89.2 % in 2021, suggesting that fine particles are the main contributors to total PM10 absorption and that the contribution of fine particles to absorption became more important. The absorption Ångström exponent (AAE) in winter decreased from 2018 to 2021, implying a decreasing contribution from brown carbon to light absorption, which may relate to the reduced emissions of biomass burning and coal combustion. During the study period, aerosol radiative forcing efficiency became more negative, mainly influenced by increasing SSA and was −27.0 and −26.2 W m−2 per aerosol optical depth (AOD) for PM10 and PM1 in 2021. Higher σab and PM2.5 mass concentrations were primarily distributed in clusters 4 and 5, transported from the south and the west of Beijing each year. σab and PM2.5 corresponding to clusters 4 and 5 decreased evidently from 2018 to 2021, which may result from the control of source emissions in surrounding regions of Beijing. The 4-year data presented in this study provide critical optical parameters for radiative forcing assessment within two size ranges and are helpful for evaluating the effectiveness of clean air action.

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Section: Temporal Variation In Aerosol Optical Propertiesmentioning

confidence: 99%

Section: Temporal Variation In Aerosol Optical Propertiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Measurement report: Rapid decline of aerosol absorption coefficient and aerosol optical property effects on radiative forcing in an urban area of Beijing from 2018 to 2021

Sun

Xia

et al. 2023

Atmos. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…Methods attempting to apportion ambient PM to their emission sources are relatively mature (Hopke, 2016), and substantial efforts have been made over the past five decades to analyze observational data using statistical methods (Briggs & Long, 2016; Kirago et al., 2022; W. G. Li et al., 2022; Y. L. Zhang et al., 2015; H. Zheng et al., 2019). The selection of an appropriate statistical method relies on the availability of data obtained from field measurements.…”

Section: Introductionmentioning

confidence: 99%

“…The aethalometer BC can be apportioned by relating BC absorption measurements at wavelengths of 470 (or 370) nm and 950 (or 880) nm to the Absorption Ångström Exponent (AAE) characteristics of the sources. However, only two general sources, fossil fuel and biomass burning (BB) sources (or liquid fossil fuel and solid fuel burning), can be identified using the aethalometer method (Dumka et al., 2018; W. G. Li et al., 2022; Nie et al., 2022), which is far less than the diverse emission sources in the real world. Receptor models, such as positive matrix factorization (PMF), can achieve more accurate BC source apportionment if chemical compositional data are available (Briggs & Long, 2016; H. K. Liu et al., 2021, 2022).…”

Section: Introductionmentioning

confidence: 99%

Measuring the Emission Changes and Meteorological Dependence of Source‐Specific BC Aerosol Using Factor Analysis Coupled With Machine Learning

Dai

Ding

et al. 2023

JGR Atmospheres

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Reducing ambient black carbon (BC) relies on the targeted control of anthropogenic emissions. Measuring emission changes in source‐specific BC aerosol is essential to assess the effectiveness of regulatory policies but is difficult due to the presence of meteorology and multiple co‐existing emissions. Herein, we propose a data‐driven approach, combining dispersion‐normalized factor analysis (DN‐PMF) with a machine learning weather adjustment (deweathering) technique, to decompose ambient BC into source emissions and meteorological drivers. Six refined BC sources were extracted from the factor analysis of aethalometer multi‐wavelength BC and concurrent observational datasets. In addition to the widely reported dominant sources, such as vehicular emissions (VE) and coal/biomass burning (BB), a discernible port and shipping emission source were identified with potential impacts on coastal air quality. The source‐specific BC showed abrupt changes in response to interventions (e.g., holidays) after separating weather‐related confounders. Significant reductions in deweathered coal and BB, VE, and local dust verified the effectiveness of policies, such as clean winter‐heating and support for the Clean Air Actions. As revealed by a post‐hoc model explanation technique, the evolution of the boundary layer was the predominant meteorological driver exerting the opposite impact on local sources with respect to distant regional‐wide sources, that is, the port and shipping emissions.

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Beyond common urban air quality assessment: Relationship between PM2.5 and black carbon during haze and non-haze periods in Bangkok

Choomanee,

Bualert,

Thongyen

et al. 2024

Atmospheric Pollution Research

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A one-year study on black carbon in urban Beijing: Concentrations, sources and implications on visibility

Cited by 7 publications

References 56 publications

Measurement report: Rapid decline of aerosol absorption coefficient and aerosol optical property effects on radiative forcing in an urban area of Beijing from 2018 to 2021

Measurement report: Rapid decline of aerosol absorption coefficient and aerosol optical property effects on radiative forcing in an urban area of Beijing from 2018 to 2021

Measuring the Emission Changes and Meteorological Dependence of Source‐Specific BC Aerosol Using Factor Analysis Coupled With Machine Learning

Beyond common urban air quality assessment: Relationship between PM2.5 and black carbon during haze and non-haze periods in Bangkok

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