Review of "The single-particle mixing state and cloud scavenging of black carbon at a high-altitude mountain site in southern China"

2017 ◽  
Author(s):  
Anonymous
Keyword(s):  
High Altitude ◽  
Black Carbon ◽  
Single Particle ◽  
Southern China ◽  
Mixing State ◽  
Particle Mixing ◽  
Mountain Site ◽  
Cloud Scavenging

scholarly journals The single-particle mixing state and cloud scavenging of black carbon at a high-altitude mountain site in southern China

2017 ◽  
Author(s):  
Guohua Zhang ◽  
Qinhao Lin ◽  
Long Peng ◽  
Xinhui Bi ◽  
Duohong Chen ◽  
...  
Keyword(s):  
Black Carbon ◽  
Single Particle ◽  
Southern China ◽  
Climate Impacts ◽  
Limited Information ◽  
Mixing State ◽  
Cloud Droplets ◽  
Mountain Site ◽  
Cloud Scavenging ◽  
Scavenging Efficiency

Abstract. In the present study, a ground-based counterflow virtual impactor (GCVI) was used to sample cloud droplet residual (cloud RES) particles, while a parallel PM2.5 inlet was used to sample cloud-free or cloud interstitial (cloud INT) particles. The mixing state of black carbon (BC)-containing particles in a size range of 0.1–1.6 µm and the mass concentrations of BC in the cloud-free, RES and INT particles were investigated using a single particle aerosol mass spectrometer (SPAMS) and two aethalometers, respectively, at a mountain site (1690 m a.s.l.) in southern China. The measured BC-containing particles were internally mixed extensively with sulfate, and were activated into cloud droplets to the same extent as all the measured particles. The results indicate the preferential activation of larger particles and/or that the production of secondary compositions shifts the BC-containing particles towards larger sizes. BC-containing particles with an abundance of both sulfate and organics were activated less than those with sulfate but limited organics, implying the importance of the mixing state on the incorporation of BC-containing particles into cloud droplets. The mass scavenging efficiency of BC with an average of 33 % was similar for different cloud events independent of the air mass. This is the first time that both the mixing state and cloud scavenging of BC in China have been reported. Since limited information on BC-containing particles in the free troposphere is available, the results also provide an important reference for the representation of BC concentrations, properties, and climate impacts in modeling studies.

scholarly journals The single-particle mixing state and cloud scavenging of black carbon: a case study at a high-altitude mountain site in southern China

2017 ◽  
Vol 17 (24) ◽  
pp. 14975-14985 ◽  
Author(s):  
Guohua Zhang ◽  
Qinhao Lin ◽  
Long Peng ◽  
Xinhui Bi ◽  
Duohong Chen ◽  
...  
Keyword(s):  
Black Carbon ◽  
Single Particle ◽  
Southern China ◽  
Cloud Droplet ◽  
Mixing State ◽  
Cloud Droplets ◽  
Aerosol Mass ◽  
Mountain Site ◽  
Cloud Scavenging ◽  
Scavenging Efficiency

Abstract. In the present study, a ground-based counterflow virtual impactor (GCVI) was used to sample cloud droplet residual (cloud RES) particles, while a parallel PM2.5 inlet was used to sample cloud-free or cloud interstitial (cloud INT) particles. The mixing state of black carbon (BC)-containing particles and the mass concentrations of BC in the cloud-free, RES and INT particles were investigated using a single-particle aerosol mass spectrometer (SPAMS) and two aethalometers, respectively, at a mountain site (1690 m a. s. l. ) in southern China. The measured BC-containing particles were extensively internally mixed with sulfate and were scavenged into cloud droplets (with number fractions of 0.05–0.45) to a similar (or slightly lower) extent as all the measured particles (0.07–0.6) over the measured size range of 0.1–1.6 µm. The results indicate the preferential activation of larger particles and/or that the production of secondary compositions shifts the BC-containing particles towards larger sizes. BC-containing particles with an abundance of both sulfate and organics were scavenged less than those with sulfate but limited organics, implying the importance of the mixing state on the incorporation of BC-containing particles into cloud droplets. The mass scavenging efficiency of BC with an average of 33 % was similar for different cloud events independent of the air mass. This is the first time that both the mixing state and cloud scavenging of BC in China have been reported. Our results would improve the knowledge on the concentration, mixing state, and cloud scavenging of BC in the free troposphere.

scholarly journals Characterising mass-resolved mixing state of black carbon in Beijing using a morphology-independent measurement method

2020 ◽  
Vol 20 (6) ◽  
pp. 3645-3661 ◽  
Author(s):  
Chenjie Yu ◽  
Dantong Liu ◽  
Kurtis Broda ◽  
Rutambhara Joshi ◽  
Jason Olfert ◽  
...  
Keyword(s):  
Black Carbon ◽  
Atmospheric Aerosols ◽  
Particle Morphology ◽  
Urban Site ◽  
Inversion Method ◽  
Mixing State ◽  
State Index ◽  
Cloud Scavenging ◽  
Highly Correlated ◽  
State Mixing

Abstract. Refractory black carbon (rBC) in the atmosphere is known for its significant impacts on climate. The relationship between the microphysical and optical properties of rBC remains poorly understood and is influenced by its size and mixing state. Mixing state also influences its cloud scavenging potential and thus atmospheric lifetime. This study presents a coupling of a centrifugal particle mass analyser (CPMA) and a single-particle soot photometer (SP2) for the morphology-independent quantification of the mixing state of rBC-containing particles, used in the urban site of Beijing as part of the Air Pollution and Human Health–Beijing (APHH-Beijing) project during winter (10 November–10 December 2016) and summer (18 May–25 June 2017). This represents a highly dynamic polluted environment with a wide variety of conditions that could be considered representative of megacity area sources in Asia. An inversion method (used for the first time on atmospheric aerosols) is applied to the measurements to present two-variable distributions of both rBC mass and total mass of rBC-containing particles and calculate the mass-resolved mixing state of rBC-containing particles, using previously published metrics. The mass ratio between non-rBC material and rBC material (MR) is calculated to determine the thickness of a hypothetical coating if the rBC and other material followed a concentric sphere model (the equivalent coating thickness). The bulk MR (MRbulk) was found to vary between 2 and 12 in winter and between 2 and 3 in summer. This mass-resolved mixing state is used to derive the mass-weighted mixing state index for the rBC-containing particles (χrBC). χrBC quantifies how uniformly the non-rBC material is distributed across the rBC-containing-particle population, with 100 % representing uniform mixing. The χrBC in Beijing varied between 55 % and 70 % in winter depending on the dominant air masses, and χrBC was highly correlated with increased MRbulk and PM1 mass concentration in winter, whereas χrBC in summer varied significantly (ranging 60 %–75 %) within the narrowly distributed MRbulk and was found to be independent of air mass sources. In some model treatments, it is assumed that more atmospheric ageing causes the BC to tend towards a more homogeneous mixture, but this leads to the conclusion that the MRbulk may only act as a predictor of χrBC in winter. The particle morphology-independent and mass-based information on BC mixing used in this and future studies can be applied to mixing-state-aware models investigating atmospheric rBC ageing.

scholarly journals Correlation of black carbon aerosol and carbon monoxide concentrations measured in the high-altitude environment of Mt. Huangshan, Eastern China

2011 ◽  
Vol 11 (2) ◽  
pp. 4447-4485 ◽  
Author(s):  
X. L. Pan ◽  
Y. Kanaya ◽  
Z. F. Wang ◽  
Y. Liu ◽  
P. Pochanart ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
High Altitude ◽  
Black Carbon ◽  
Urban Areas ◽  
Southern China ◽  
Eastern China ◽  
Back Trajectory ◽  
Strong Positive Correlation ◽  
Air Mass ◽  
Co Concentration

Abstract. Understanding the relationship between black carbon (BC) and carbon monoxide (CO) will help improve BC emission inventories and the evaluation of global/regional climate forcing effects. In the present work, the BC (PM1) and CO mixing ratio was continuously measured at a~high-altitude background station on the summit of Mt Huangshan between 2006 and 2009. Annual mean BC concentration was 654.6 ± 633.4 ng m−3 with maxima in spring and autumn, when biomass was burned over a large area in Eastern China. The yearly averaged CO concentration was 446.4 ± 167.6 ppbv, and the increase in the CO concentration was greatest in the cold season, implying that the large-scale domestic coal/biofuel combustion for heating has an effect. The BC–CO relationship was found to have different seasonal features but strong positive correlation (R > 0.8). Back trajectory cluster analysis showed that the ΔBC/ΔCO ratio of plumes from the Yangtze River Delta region was 6.58 ± 0.96 ng m−3 ppbv−1, which is consistent with result from INTEX-B emission inventory. The ΔBC/ΔCO ratios for air masses from Northern, Central Eastern and Southern China were 5.2 ± 0.63, 5.65 ± 0.58 and 5.21 ± 0.93 ng m−3 ppbv−1, respectively. Over the whole observation period, the ΔBC/ΔCO ratio had unimodal diurnal variations and had a maximum during the day (09:00–17:00 LST) and minimum at night (21:00–04:00 LST) in spring, summer, autumn and winter, indicating the effects of the intrusion of clean air mass from the high troposphere. The case study combined with measurements of urban PM10 concentrations and satellite observations demonstrated that the ΔBC/ΔCO ratio for a plume of burning biomass was 12.4 ng m−3 ppbv−1 and that for urban plumes in Eastern China was 5.3 ± 0.53 ng m−3 ppbv−1. Transportation and industry were deemed as controlling factors of the BC–CO relationship and major contributions to atmospheric BC and CO loadings in urban areas. The loss of BC during transportation was also investigated on the basis of the ΔBC/ΔCO–RH relationship along air mass pathways, and the results showed that 30–50% BC was lost when air mass traveled under higher RH conditions (>60%) for 2 days.

scholarly journals Single particle characterization of biomass burning organic aerosol (BBOA): evidence for non-uniform mixing of high molecular weight organics and potassium

2015 ◽  
Vol 15 (22) ◽  
pp. 32157-32183 ◽  
Author(s):  
A. K. Y. Lee ◽  
M. D. Willis ◽  
R. M. Healy ◽  
J. M. Wang ◽  
C.-H. Jeong ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Black Carbon ◽  
High Molecular Weight ◽  
Biomass Burning ◽  
Single Particle ◽  
Critical Role ◽  
Organic Aerosol ◽  
Mixing State ◽  
Particle Measurements ◽  
Near Ultraviolet

Abstract. Biomass burning is a major source of black carbon (BC) and primary organic aerosol globally. In particular, biomass burning organic aerosol (BBOA) is strongly associated with atmospheric brown carbon (BrC) that absorbs near ultraviolet and visible light, resulting in significant impacts on regional visibility degradation and radiative forcing. The mixing state of BBOA can play a critical role in the prediction of aerosol optical properties. In this work, single particle measurements from a soot-particle aerosol mass spectrometer coupled with a light scattering module (LS-SP-AMS) were performed to examine the mixing state of BBOA, refractory black carbon (rBC) and potassium (K+, a tracer for biomass burning aerosol) in an air mass influenced by aged biomass burning. Cluster analysis of single particle measurements identified five BBOA-related particle types. rBC accounted for 3–14 w.t. % of these particle types on average. Only one particle type exhibited a strong ion signal for K+, with mass spectra characterized by low molecular weight organic species. The remaining four particle types were classified based on the apparent molecular weight of the BBOA constituents. Two particle types were associated with low potassium content and significant amounts of high molecular weight (HMW) organic compounds. Our observations indicate non-uniform mixing of particles within a biomass burning plume in terms of molecular weight and illustrate that HMW BBOA can be a key contributor to low-volatility BrC observed in BBOA particles.

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