Morphology, Composition, and Mixing State of Individual Aerosol Particles in Northeast China during Wintertime

Xu, Liang; Liu, Lei; Zhang, Jian; Zhang, Yinxiao; Ren, Yong; Wang, Xin; Li, Weijun

doi:10.3390/atmos8030047

Cited by 18 publications

(14 citation statements)

References 27 publications

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“…Similar results that secondary aerosol formation causes heavy winter hazes in the NCP have been well documented (Y. Sun et al, 2014;Xue et al, 2016;. Because of low O 3 levels at 12 ppb (Fig.…”

Section: Sources and Formation Of Two Distinctive Haze Eventssupporting

confidence: 82%

Exploring wintertime regional haze in northeast China: role of coal and biomass burning

Zhang

Liu

et al. 2020

Atmos. Chem. Phys.

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Abstract. As one of the intense anthropogenic emission regions across the relatively high-latitude (>40∘ N) areas on Earth, northeast China faces the serious problem of regional haze during the heating period of the year. Aerosols in polluted haze in northeast China are poorly understood compared with the haze in other regions of China such as the North China Plain. Here, we integrated bulk chemical measurements with single-particle analysis from transmission electron microscopy (TEM), nanoscale secondary ion mass spectrometry (NanoSIMS), and atomic force microscopy (AFM) to obtain morphology, size, composition, aging process, and sources of aerosol particles collected during two contrasting regional haze events (Haze-I and Haze-II) at an urban site and a mountain site in northeast China and further investigated the causes of regional haze formation. Haze-I evolved from moderate (average PM2.5: 76–108 µg m−3) to heavy pollution (151–154 µg m−3), with the dominant PM2.5 component changing from organic matter (OM) (39–45 µg m−3) to secondary inorganic ions (94–101 µg m−3). Similarly, TEM observations showed that S-rich particles internally mixed with OM (named S-OM) increased from 29 % to 60 % by number at an urban site and 64 % to 74 % at a mountain site from the moderate Haze-I to heavy Haze-I events, and 75 %–96 % of Haze-I particles included primary OM. We found that change of wind direction caused Haze-I to rapidly turn into Haze-II (185–223 µg m−3) with predominantly OM (98–133 µg m−3) and unexpectedly high K+ (3.8 µg m−3). TEM also showed that K-rich particles internally mixed with OM (named K-OM) increased from 4 %–5 % by number to 50 %–52 %. The results indicate that there were different sources of aerosol particles causing the Haze-I and Haze-II formation: Haze-I was mainly induced by accumulation of primary OM emitted from residential coal burning and further deteriorated by secondary aerosol formation via heterogeneous reactions; Haze-II was caused by long-range transport of agricultural biomass burning emissions. Moreover, abundant primary OM particles emitted from coal and biomass burning were considered to be one typical brown carbon, i.e., tar balls. Our study highlights that large numbers of light-absorbing tar balls significantly contribute to winter haze formation in northeast China and they should be further considered in climate models.

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Section: Sources and Formation Of Two Distinctive Haze Eventssupporting

confidence: 82%

Exploring wintertime regional haze in northeast China: role of coal and biomass burning

Zhang

Liu

et al. 2020

Atmos. Chem. Phys.

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“…Li et al (2012) found a large number of spherical POA particles in a coal-burning area over the China Loess Plateau during the winter heating period. POA particles were the most abundant in winter at the rural site in Northeast China (Xu et al, 2017). Moreover, some studies noted that the concentrations of organic particles from emissions of industrial boiler and coal-fired power plants were far lower than those from coal and biomass burning in residential stoves (Liu et al, 2016;Zhang et al, 2008).…”

Section: Sources Of Organic Particlesmentioning

confidence: 99%

Chemical composition, source, and process of urban aerosols during winter haze formation in Northeast China

Zhang

Liu

Wang

et al. 2017

Environmental Pollution

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The characteristics of aerosol particles have been poorly evaluated even though haze episodes frequently occur in winter in Northeast China. OC/EC analysis, ion chromatography, and transmission electron microscopy (TEM) were used to investigate the organic carbon (OC) and elemental carbon (EC), and soluble ions in PM and the mixing state of individual particles during a severe wintertime haze episode in Northeast China. The organic matter (OM), NH, SO, and NO concentrations in PM were 89.5 μg/m, 24.2 μg/m, 28.1 μg/m, and 32.8 μg/m on the haze days, respectively. TEM observations further showed that over 80% of the haze particles contained primary organic aerosols (POAs). Based on a comparison of the data obtained during the haze formation, we generate the following synthetic model of the process: (1) Stable synoptic meteorological conditions drove the haze formation. (2) The early stage of haze formation (light or moderate haze) was mainly caused by the enrichment of POAs from coal burning for household heating and cooking. (3) High levels of secondary organic aerosols (SOAs), sulfates, and nitrates formation via heterogeneous reactions together with POAs accumulation promoted to the evolution from light or moderate to severe haze. Compared to the severe haze episodes over the North China Plain, the PM in Northeast China analyzed in the present study contained similar sulfate, higher SOA, and lower nitrate contents. Our results suggest that most of the POAs and secondary particles were likely related to emissions from coal-burning residential stoves in rural outskirts and small boilers in urban areas. The inefficient burning of coal for household heating and cooking should be monitored during wintertime in Northeast China.

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“…These secondary particles are mainly composed of element C, O, S and minor N and are defined as S-rich particles [18,20]. We infer that they indeed are mixtures of sulfate, nitrate, and/or organic matter (OM) in the atmosphere [18].…”

Section: Nature Of Individual Aerosol Particlesmentioning

confidence: 91%

“…Elemental composition was semi-quantitatively determined by energy-dispersive X-ray spectrometer (EDX) with a spectral acquisition time of~30 s and elements heavier than C (Z ≥ 6) can be detected [20]. Copper (Cu) was not included from our analysis because the TEM grids were made of Cu.…”

Section: Tem Analysismentioning

confidence: 99%

Physicochemical Characteristics of Individual Aerosol Particles during the 2015 China Victory Day Parade in Beijing

et al. 2018

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During the 2015 China Victory Day parade control periods, the air quality in Beijing hit the best record, leading to 15 continuous good days with an average PM 2.5 mass concentration 18 µg/m 3 , which provided a unique opportunity to study the ambient aerosols in megacity Beijing. The morphology and elemental composition of aerosol particles were investigated by transmission electron microscopy coupled with energy dispersive X-ray spectrometry (TEM-EDX). Five types of individual particles were identified, including homogeneous mixed S-rich particles (HS; 44.9%), organic coated S-rich particles (CS; 34.3%), mineral particles (10.5%), soot aggregates (7.21%) and organic particles (3.2%). The number percentage of secondary particles (including HS and CS) accounted for a large proportion with 79.2% during the control periods. The average diameter of secondary particles increased with relative humidity (RH), being 323 nm, 358 nm and 397 nm at the RH 34%, 43% and 53%, respectively, suggesting that the high RH might favor the growth of secondary particles. The higher proportion of CS particles may show great atmospheric implications and the CS particles may be formed by the condensation of secondary organic aerosols on pre-existing S-rich particles.

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Morphology, Composition, and Mixing State of Individual Aerosol Particles in Northeast China during Wintertime

Cited by 18 publications

References 27 publications

Exploring wintertime regional haze in northeast China: role of coal and biomass burning

Exploring wintertime regional haze in northeast China: role of coal and biomass burning

Chemical composition, source, and process of urban aerosols during winter haze formation in Northeast China

Physicochemical Characteristics of Individual Aerosol Particles during the 2015 China Victory Day Parade in Beijing

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