scholarly journals Review for the “Direct observations of organic aerosols in common wintertime hazes in North China: insights into their size, shape, mixing state, and source” by Chen et al.

2016 ◽  
Author(s):  
Anonymous
Keyword(s):  
North China ◽  
Organic Aerosols ◽  
Mixing State ◽  
Direct Observations

scholarly journals Direct observations of organic aerosols in common wintertime hazes in North China: insights into their size, shape, mixing state, and source

2016 ◽  
Author(s):  
S. R. Chen ◽  
L. Xu ◽  
Y. X. Zhang ◽  
B. Chen ◽  
X. F. Wang ◽  
...  
Keyword(s):  
Rural Areas ◽  
Coal Combustion ◽  
North China ◽  
Fine Particles ◽  
Organic Aerosols ◽  
Urban Site ◽  
Mixing State ◽  
Spherical Type ◽  
Coating Type

Abstract. Many studies have focused on the physicochemical properties of aerosol particles in unusually severe haze episodes instead of the more freqent and less severe hazes. Consistent with this lack of attention, the morphology and mixing state of organic matter (OM) particles in the frequent light and moderate (L&M) hazes in winter in North China Plain (NCP) have not been examined, even though OM dominates these fine particles. In the present work, morphology, mixing state, and size of organic aerosols in the L&M hazes were systematically characterized using transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy, atomic force microscopy, and nanoscale secondary ion mass spectrometer, with the comparisons among an urban site (Jinan, S1), a mountain site (Tai, S2), and a background island site (Changdao, S3) in the same hazes. Based on their morphology, the OM particles were divided into six different types: spherical (type 1), near-spherical (type 2), irregular (type 3), domelike (type 4), dispersed-OM (type 5), and OM-coating (type 6). In the three sampling sites, type 1–3 of OM particles were most abundant in the L&M hazes and most of them were internally mixed with non-OM particles. The abundant near-spherical OM particles with higher sphericity and lower aspect ratio indicate that these primary OM particles formed in cooling, polluted plumes from coal combustion and biomass burning. Based on the Si-O-C ratio in OM particles, we estimated that 71 % of type 1–3 OM particles were associated with coal combustion. Our result suggests that coal combustion in residential stoves was a widespread source from urban to rural areas in the NCP. Average OM thickness which correlates with the age of the air masses in type 6 particles only slightly increased from S3 to S2 to S1, suggesting that the L&M hazes were usually dry (relative humidity 

scholarly journals Direct observations of organic aerosols in common wintertime hazes in North China: insights into direct emissions from Chinese residential stoves

2017 ◽  
Vol 17 (2) ◽  
pp. 1259-1270 ◽  
Author(s):  
Shurui Chen ◽  
Liang Xu ◽  
Yinxiao Zhang ◽  
Bing Chen ◽  
Xinfeng Wang ◽  
...  
Keyword(s):  
Rural Areas ◽  
Coal Combustion ◽  
North China ◽  
Fine Particles ◽  
Organic Aerosols ◽  
Heterogeneous Reactions ◽  
Urban Site ◽  
Mixing State ◽  
Spherical Type

Abstract. Many studies have focused on the physicochemical properties of aerosol particles in unusually severe haze episodes in North China instead of the more frequent and less severe hazes. Consistent with this lack of attention, the morphology and mixing state of organic matter (OM) particles in the frequent light and moderate (L &amp; M) hazes in winter in the North China Plain (NCP) have not been examined, even though OM dominates these fine particles. In the present work, morphology, mixing state, and size of organic aerosols in the L &amp; M hazes were systematically characterized using transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy, atomic force microscopy, and nanoscale secondary ion mass spectrometer, with the comparisons among an urban site (Jinan, S1), a mountain site (Mt. Tai, S2), and a background island site (Changdao, S3) in the same hazes. Based on their morphologies, the OM particles were divided into six different types: spherical (type 1), near-spherical (type 2), irregular (type 3), domelike (type 4), dispersed-OM (type 5), and OM-coating (type 6). In the three sampling sites, types 1–3 of OM particles were most abundant in the L &amp; M hazes and most of them were internally mixed with non-OM particles. The abundant near-spherical OM particles with higher sphericity and lower aspect ratio indicate that these primary OM particles formed in the cooling process after polluted plumes were emitted from coal combustion and biomass burning. Based on the Si-O-C ratio in OM particles, we estimated that 71 % of type 1–3 OM particles were associated with coal combustion. Our result suggests that coal combustion in residential stoves was a widespread source from urban to rural areas in NCP. Average OM thickness which correlates with the age of the air masses in type 6 particles only slightly increased from S1 to S2 to S3, suggesting that the L &amp; M hazes were usually dry (relative humidity < 60 %) with weak photochemistry and heterogeneous reactions between particles and gases. We conclude that the direct emissions from these coal stoves without any pollution controls in rural areas and in urban outskirts contribute large amounts of primary OM particles to the regional L &amp; M hazes in North China.

scholarly journals Influence of biomass burning on mixing state of sub-micron aerosol particles in the North China Plain

2017 ◽  
Vol 164 ◽  
pp. 259-269 ◽  
Author(s):  
Simonas Kecorius ◽  
Nan Ma ◽  
Monique Teich ◽  
Dominik van Pinxteren ◽  
Shenglan Zhang ◽  
...  
Keyword(s):  
Biomass Burning ◽  
North China Plain ◽  
North China ◽  
Aerosol Particles ◽  
Mixing State ◽  
The North ◽  
The North China Plain

scholarly journals Mixing state of individual submicron carbon-containing particles during spring and fall seasons in urban Guangzhou, China: a case study

2013 ◽  
Vol 13 (9) ◽  
pp. 4723-4735 ◽  
Author(s):  
G. Zhang ◽  
X. Bi ◽  
L. Li ◽  
L. Y. Chan ◽  
M. Li ◽  
...  
Keyword(s):  
Single Particle ◽  
Climate Forcing ◽  
Mixing State ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Acidity ◽  
Direct Observations ◽  
Aerosol Mass ◽  
The Pearl River ◽  
Biomass Particles

Abstract. Growing evidence suggests that the size-resolved mixing state of carbon-containing particles is very critical in determining their optical properties, atmospheric lifetime, and impact on the environment. However, still little is known about the mixing state of particles in the urban area of the Pearl River Delta (PRD) region, China. To investigate the mixing state of submicron carbon-containing particles, measurements were carried out during spring and fall periods of 2010 using a single-particle aerosol mass spectrometer (SPAMS). Approximately 700 000 particles for each period were detected. This is the first report on the size-resolved mixing state of carbon-containing particles by direct observations in the PRD region. Cluster analysis of single-particle mass spectra was applied to identify carbon-containing particle classes. These classes represented ~80% and ~90% of all the detected particles for spring and fall periods, respectively. Carbon-containing particle classes mainly consisted of biomass/biofuel burning particles (Biomass), organic carbon (OC), fresh elemental carbon (EC-fresh), internally mixed OC and EC (ECOC), internally mixed EC with sulfate (EC-Sulfate), vanadium-containing ECOC (V-ECOC), and amines-containing particles (Amine). In spring, the top three ranked carbon-containing particle classes were ECOC (26.1%), Biomass (23.6%) and OC (10%), respectively. However, the fraction of Biomass particles increased remarkably and predominated (61.0%), while the fraction of ECOC (3.0%) and V-ECOC (0.1%) significantly decreased in fall. To highlight the influence of monsoon on the properties of carbon-containing particles in urban Guangzhou, their size distributions, mixing state, and aerosol acidity were compared between spring and fall seasons. In addition, a case study was also performed to investigate how the formation of fog and haze influenced the mixing state of carbon-containing particles. These results could improve our understanding of the mixing state of carbon-containing particles, and may also be helpful in modeling the climate forcing of aerosol in the PRD region.

scholarly journals MATRIX-VBS (v1.0): implementing an evolving organic aerosol volatility in an aerosol microphysics model

2017 ◽  
Vol 10 (2) ◽  
pp. 751-764 ◽  
Author(s):  
Chloe Y. Gao ◽  
Kostas Tsigaridis ◽  
Susanne E. Bauer
Keyword(s):  
Organic Matter ◽  
Volatile Component ◽  
Organic Aerosols ◽  
Organic Aerosol ◽  
Basis Set ◽  
Oh Radicals ◽  
Mixing State ◽  
Organic Species ◽  
Parallel Simulations ◽  
Southeastern Us

Abstract. The gas-particle partitioning and chemical aging of semi-volatile organic aerosol are presented in a newly developed box model scheme, where its effect on the growth, composition, and mixing state of particles is examined. The volatility-basis set (VBS) framework is implemented into the aerosol microphysical scheme MATRIX (Multiconfiguration Aerosol TRacker of mIXing state), which resolves mass and number aerosol concentrations and in multiple mixing-state classes. The new scheme, MATRIX-VBS, has the potential to significantly advance the representation of organic aerosols in Earth system models by improving upon the conventional representation as non-volatile particulate organic matter, often also with an assumed fixed size distribution. We present results from idealized cases representing Beijing, Mexico City, a Finnish forest, and a southeastern US forest, and investigate the evolution of mass concentrations and volatility distributions for organic species across the gas and particle phases, as well as assessing their mixing state among aerosol populations. Emitted semi-volatile primary organic aerosols evaporate almost completely in the intermediate-volatility range, while they remain in the particle phase in the low-volatility range. Their volatility distribution at any point in time depends on the applied emission factors, oxidation by OH radicals, and temperature. We also compare against parallel simulations with the original scheme, which represented only the particulate and non-volatile component of the organic aerosol, examining how differently the condensed-phase organic matter is distributed across the mixing states in the model. The results demonstrate the importance of representing organic aerosol as a semi-volatile aerosol, and explicitly calculating the partitioning of organic species between the gas and particulate phases.

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