Integrated evaluation of aerosols during haze-fog episodes at one regional background site in North China Plain

Yuan, Qi; Li, Weijun; Zhou, Shengzhen; Yang, Lingxiao; Chi, Jianwei; Sui, Xiao; Wang, Wenxing

doi:10.1016/j.atmosres.2015.01.002

Cited by 63 publications

(35 citation statements)

References 42 publications

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“…The associated metallic species were mainly 39[K] + , 23[Na] + , and 56[Fe] + , likely produced by the metal industry [ Taiwo et al , ]. The EC‐containing particles were found to be internally mixed with sulfate and nitrate, indicating some degree of atmospheric aging or fog processing [ Dall ' Osto et al , ; Ram et al , ; Yuan et al , ].…”

Section: Resultsmentioning

confidence: 99%

In situ detection of the chemistry of individual fog droplet residues in the Pearl River Delta region, China

Lin

Peng

et al. 2016

JGR Atmospheres

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We use a single‐particle aerosol mass spectrometer coupled with a ground‐based counterflow virtual impactor to measure the chemical compositions of individual submicron fog droplet residues. This is the first report on single particle mass spectrometry measurements of fog droplet residual particles at ground level in an urban area. We show that most of the fog droplet residues were composed of elemental carbon (EC) (67.7%), followed by K‐rich (19.2%) and mineral dust/metal (12.3%) particles. The predominance of EC‐containing particles demonstrated that these particles could be effective fog nuclei and highlights the important influence of anthropogenic emissions on regional climate system. Compared with interstitial and ambient aerosols, nitrate was enhanced, sulfate was depressed, and ammonium‐ and organics‐containing particles were hardly found in the fog droplet residues during fog events, suggesting that dust and metal particles containing nitrate may be preferentially activated and that ammonium and organics may not play important roles in fog formation in Guangzhou. We also present direct observational evidence that trimethylamine and hydroxymethanesulfonate are not found within fog droplet residues, although we previously observed enhanced gas‐to‐particle partitioning of these compounds by fog processing. Additionally, higher fraction or intensities of [K]+, [Fe]+, and [SiO3]− were found in fog droplet residues than in ambient and interstitial particles.

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Section: Resultsmentioning

confidence: 99%

In situ detection of the chemistry of individual fog droplet residues in the Pearl River Delta region, China

Lin

Peng

et al. 2016

JGR Atmospheres

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“…Atmospheric particles undergo liquidliquid phase separations and go on to form OM coatings on inorganic aerosol particles (You et al, 2012). The surface coating by OM on individual particles influences water uptake and evaporation of individual particles and their heterogeneous reactions in the atmosphere (Shiraiwa et al, 2011;Zawadowicz et al, 2015;Riipinen et al, 2011). Despite the importance of these phenomena, the morphology and mixing state of OM particles in wintertime L & M hazes in the NCP have not been examined, although OM is dominant in fine particles (Sun et al, 2013).…”

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confidence: 99%

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

Chen

Zhang

et al. 2017

Atmos. Chem. Phys.

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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 & 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 & 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 & 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 & 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 & M hazes in North China.

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“…These results indicated that marine sources are not the dominant origin of these ions. The mass ratio of Na + /SO4 2is 0.17 and 0.24 in the high and low pollution samples, repsectively, much lower than that of seawater (3.98), reconfirming that marine source was not pridominant (Yuan et al, 2015). The high value of nss-Ca 2+ /Ca 2+ indicate a large amount of continental contribution to atmospheric Ca 2+ .…”

Section: Inorganic Ionsmentioning

confidence: 61%

Aerosol composition and sources during high and low pollution periods in Ningbo, China

Xiao

et al. 2016

Atmospheric Research

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Due to the rapid industrialization of the Yangtze River Delta (YRD) region in China, heavy air pollution episodes have occurred frequently over the past five years which are of great concern due to their environmental and health impacts. To investigate the chemical characteristics of the highly polluted aerosols in this region, a sampling campaign had been conducted in Ningbo from 3 December 2012 to 27 June 2013, during which a month long high pollution episode had been captured. Daily average PM2.5 concentrations during high and low pollution periods were 111 μg m-³ and 53 μg m-³, respectively. The most polluted day was 8 January 2013 with a PM2.5 concentration up to 175 μg m-3. To understand the origin of the highly polluted aerosols, meteorological conditions, air mass backward trajectories, distribution of fire spots in surrounding areas and various categories of aerosol pollutants were analysed, including trace metals, inorganic species, PAHs and anhydrosugars. Total metal concentrations were 3.8 and 1.6 μg m-³ for the high and low pollution episodes, respectively, accounting for 3.4% and 3.1% of the total PM2.5 mass. Total concentrations of ionic species accounted for more than 50.0% of the PM2.5 by mass, with dominant ions (nitrate, sulphate, ammonium) accounting for over 42.0% of the PM2.5 mass concentrations in both periods. During the high pollution episode, enhanced Cd-Pb and biomarker (levoglucosan, mannosan) levels indicated the contributions from coal combustion, traffic and biomass burning to fine aerosol PM2.5. The average diagnostic ratio of Fla/(Fla+Pyr) was 0.54 in high pollution episode, which was intermediate between that for wood (>0.50) and coal combustion (0.58). BaP/Bpe was 0.49 and 0.30 for the highly and lightly polluted aerosols respectively, associated with the significant non-traffic emissions (<0.60). In addition, stagnant weather conditions during the high pollution period and long-range transport of air masses from heavy industries and biomass burning from northern China to Ningbo could be considered as the main factors for the formation of the aerosols during high pollution period.

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Integrated evaluation of aerosols during haze-fog episodes at one regional background site in North China Plain

Cited by 63 publications

References 42 publications

In situ detection of the chemistry of individual fog droplet residues in the Pearl River Delta region, China

In situ detection of the chemistry of individual fog droplet residues in the Pearl River Delta region, China

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

Aerosol composition and sources during high and low pollution periods in Ningbo, China

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