Potential of Polarization Lidar to Profile the Urban Aerosol Phase State during Haze Episodes

Tan, Wangshu; Li, Chengcai; Liu, Yuechen; Meng, Xiangzhi; Wu, Zhijun; Kang, Ling; Zhu, Tong

doi:10.1021/acs.estlett.9b00695

Cited by 14 publications

(9 citation statements)

References 46 publications

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“…All elemental ratios of OA in this study were calculated by the "Improved-Ambient (I-A)" method (Canagaratna et al, 2015) unless specified. The combined data from bypass and TD lines (MS bypass+TD ) were analyzed with positive matrix factorization (PMF) to resolve potential OA factors (Ulbrich et al, 2009). Four factors were identified in the summer of 2018: HOA, COA, less oxidized oxygenated OA (LO-OOA) and more oxidized OOA (MO-OOA).…”

Section: Ams Data Analysismentioning

confidence: 99%

Organic aerosol volatility and viscosity in the North China Plain: contrast between summer and winter

Chen

Qiu

et al. 2021

Atmos. Chem. Phys.

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Abstract. Volatility and viscosity have substantial impacts on gas–particle partitioning, formation and evolution of aerosol and hence the predictions of aerosol-related air quality and climate effects. Here aerosol volatility and viscosity at a rural site (Gucheng) and an urban site (Beijing) in the North China Plain (NCP) in summer and winter were investigated by using a thermodenuder coupled with a high-resolution aerosol mass spectrometer. The effective saturation concentration (C*) of organic aerosol (OA) in summer was smaller than that in winter (0.55 µg m−3 vs. 0.71–0.75 µg m−3), indicating that OA in winter in the NCP is more volatile due to enhanced primary emissions from coal combustion and biomass burning. The volatility distributions varied and were largely different among different OA factors. In particular, we found that hydrocarbon-like OA (HOA) contained more nonvolatile compounds compared to coal-combustion-related OA. The more oxidized oxygenated OA (MO-OOA) showed overall lower volatility than less oxidized OOA (LO-OOA) in both summer and winter, yet the volatility of MO-OOA was found to be relative humidity (RH) dependent showing more volatile properties at higher RH. Our results demonstrated the different composition and chemical formation pathways of MO-OOA under different RH levels. The glass transition temperature (Tg) and viscosity of OA in summer and winter are estimated using the recently developed parameterization formula. Our results showed that the Tg of OA in summer in Beijing (291.5 K) was higher than that in winter (289.7–290.0 K), while it varied greatly among different OA factors. The viscosity suggested that OA existed mainly as solid in winter in Beijing (RH = 29 ± 17 %), but as semisolids in Beijing in summer (RH = 48 ± 25 %) and Gucheng in winter (RH = 68 ± 24 %). These results have the important implication that kinetically limited gas–particle partitioning may need to be considered when simulating secondary OA formation in the NCP.

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Section: Ams Data Analysismentioning

confidence: 99%

Organic aerosol volatility and viscosity in the North China Plain: contrast between summer and winter

Chen

Qiu

et al. 2021

Atmos. Chem. Phys.

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“…The OA volatility is intrinsically related to particle phase state that plays an important role in affecting heterogeneous reactions and the formation of cloud condensation nuclei. Particle phase states have been measured by using three-arm impactor (Liu et al, 2017;Liu et al, 2019) and polarization lidar (Tan et al, 2020) in China in recent years. The results showed that particles are generally in liquid state throughout the year in south China, while there is a transition from semisolid to liquid state as RH increases above 60% in winter in NCP.…”

Section: ;mentioning

confidence: 99%

Organic aerosol volatility and viscosity in North China Plain: Contrast between summer and winter

Xu¹,

Chen²,

Qiu³

et al. 2020

Preprint

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Abstract. Volatility and viscosity have substantial impacts on gas-particle partitioning, formation and evolution of aerosol, and hence the predictions of aerosol related air quality and climate effects. Here aerosol volatility and viscosity at a rural site (Gucheng) and an urban site (Beijing) in North China Plain (NCP) in summer and winter were investigated by using a thermodenuder coupled with high resolution aerosol mass spectrometer. The effective saturation concentration (C*) of organic aerosol (OA) in summer was smaller than that in winter (0.55 μg m−3 vs. 0.71–0.75 μg m−3), indicating that OA in winter in NCP is more volatile due to enhanced primary emissions from coal combustion and biomass burning. The volatility distributions varied largely different among different OA factors. In particular, we found that hydrocarbon-like OA (HOA) contained more non-volatile compounds compared to coal combustion related OA. The more oxidized oxygenated OA (MO-OOA) showed overall lower volatility than less oxidized OOA (LO-OOA) in both summer and winter, yet the volatility of MO-OOA was found to be relative humidity (RH) dependent showing more volatile properties at higher RH. Our results demonstrated the different composition and chemical formation pathways of MO-OOA under different RH levels. The glass transition temperature (Tg) and viscosity of OA in summer and winter are estimated using the recently developed parameterization formula. Our results showed that the Tg of OA in summer in Beijing (291.5 K) was higher than that in winter (289.7–290.0 K), while it varied greatly among different OA factors. The viscosity suggested that OA existed mainly as solid in winter in Beijing, but as semi-solids in Beijing in summer and Gucheng in winter. These results have important implications that kinetically limited gas-particle partitioning may need to be considered when simulating secondary OA formation in NCP.

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“…Due to its severe impact on human health and significant atmospheric visibility reduction, Particulate Matter (PM) has attracted increasing attention worldwide (Lelieveld et al, 2015;Gu et al, 2016;An et al, 2019;Zhang et al, 2019;Zhao et al, 2020). The source and composition of PM in the atmosphere are complex, which may be generated directly by the emission sources, or generated by the secondary conversion (Zhao et al, 2018a;Tan et al, 2019). Associated with the different meteorological conditions, the size and composition of PM in the atmosphere vary widely, and could cause various health hazards and weather and climate effects over different locations (Huang et al, 2014;Lelieveld et al, 2015;Liao et al, 2015;Wang et al, 2015;Zhao et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Spatio-Temporal Variations of the PM2.5/PM10 Ratios and Its Application to Air Pollution Type Classification in China

Fan

Zhao

Yang

et al. 2021

Front. Environ. Sci.

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Particulate Matter (PM) is an important indicator of the degree of air pollution. The PM type and the ratio of coarse and fine PM particles determine the ability to affect human health and atmospheric processes. Using the observation data across the country from 2015 to 2018, this study investigates the distribution and proportion of PM2.5 and PM10 at different temporal and spatial scales in mainland China; clarifies the PM2.5, PM10 and PM2.5/PM10 ratios interrelation; and classifies the dust, mixed, and anthropogenic type aerosol. It shows that the annual average concentration of PM2.5 and PM10 decreased by 10.55 and 8.78 μg m−3 in 4 years. PM2.5, PM10, and PM2.5/PM10 ratios show obvious while different seasonal variations. PM2.5 is high in winter and low in summer, while PM10 is high in winter and spring, and low in summer and autumn. Differently, the PM2.5/PM10 ratios are the highest in winter, and the lowest in spring. PM2.5/PM10 ratios show strong independence on PM2.5 and PM10, implying that it can provide extra information about the aerosol pollution such as aerosol type. A classification method about air pollution types is then further proposed based on probability distribution function (PDF) morphology of PM2.5/PM10 ratios. The results show that dust type mainly lies in the west of Hu-Line, mixed type pollution distributes near Hu-Line, and the anthropogenic type dominates over North China Plain and cities in southern China. The results provide insights into China’s future clean air policy making and environmental research.

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Potential of Polarization Lidar to Profile the Urban Aerosol Phase State during Haze Episodes

Cited by 14 publications

References 46 publications

Organic aerosol volatility and viscosity in the North China Plain: contrast between summer and winter

Organic aerosol volatility and viscosity in the North China Plain: contrast between summer and winter

Organic aerosol volatility and viscosity in North China Plain: Contrast between summer and winter

Spatio-Temporal Variations of the PM2.5/PM10 Ratios and Its Application to Air Pollution Type Classification in China

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