Aerosol water content enhancement leads to changes in the major formation mechanisms of nitrate and secondary organic aerosols in winter over the North China plain

Abstract. Nitrate aerosol composes a significant fraction of fine particles and plays a key role in regional air quality and climate. To obtain a holistic understanding of the nitrate pollution and its formation mechanisms over the North China Plain (NCP) – the most industrialized and polluted region in northern China, intensive field observations were conducted at three sites during summertime in 2014–2015. The measurement sites include the downtown and downwind of Ji'nan, the capital city of Shandong Province, as well as the peak of NCP – Mt. Tai (1534 m a.s.l.), and hence cover representative urban, rural and remote areas of the region. Elevated nitrate concentrations were observed at all three sites despite distinct temporal and spatial variations. The nitrate / PM2.5 and nitrate / sulfate ratios have significantly increased in Ji'nan (2005–2015) and at Mt. Tai (from 2007 to 2014), indicating the worsening situation of regional nitrate pollution. A multi-phase chemical box model (RACM/CAPRAM) was deployed and constrained by observations to elucidate the nitrate formation mechanisms. The principal formation route is the partitioning of gaseous HNO3 to aerosol phase at daytime, whilst the nocturnal nitrate formation is dominated by the heterogeneous hydrolysis of N2O5. The daytime nitrate production in the NCP region is mainly limited by the availability of NO2 and to a lesser extent O3 and NH3, and the nighttime formation is controlled by both NO2 and O3. NH3 prompts significantly the nitrate formation at daytime but plays a slightly negative role in the nighttime. Our analyses suggest that controlling NOx and O3 is an efficient way at the moment to mitigate nitrate pollution in the NCP region, where NH3 is usually in excess in summer. This study provides observational evidence of rising trend of nitrate aerosol as well as scientific support for formulating effective control strategies for regional haze in China.

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On the difference of aerosol hygroscopicity between high and low RH environment in the North China Plain

10.5194/egusphere-egu21-13951 ◽

2021 ◽

Author(s):

Jingnan Shi ◽

Juan Hong ◽

Nan Ma ◽

Qingwei Luo ◽

Hanbing Xu ◽

...

Keyword(s):

Chemical Composition ◽

North China Plain ◽

North China ◽

Experimental Period ◽

Formation Mechanisms ◽

Large Contribution ◽

The North ◽

The North China Plain ◽

The Difference ◽

Aerosol Hygroscopicity

Simultaneous measurements of aerosol hygroscopicity and chemical composition were performed at a suburban site in the North China Plain in winter 2018 using a self-assembled hygroscopic tandem differential mobility analyzer (H-TDMA) and a capture-vaporizer time-of-flight aerosol chemical speciation monitor (CV-ToF-ACSM), respectively. During the experimental period, aerosol particles usually show an external mixture in terms of hygroscopicity, with a less hygroscopic particles mode (LH) and a more hygroscopic mode (MH). The average ensemble mean hygroscopicity parameter (&#954;mean) are 0.16, 0.18, 0.16, and 0.15 for 60, 100, 150, and 200 nm particles, respectively. Two episodes with different RH/T conditions and secondary aerosol formations are distinguished. Higher aerosol hygroscopicity is observed for all measured sizes in the high RH episode (HRH) than in the low RH episode (LRH). In LRH, &#954; decreases as the particle size increases, which may be explained by the large contribution of non- or less-hygroscopic primary compounds in large particles due to the enhanced domestic heating emissions at low temperature. The number fraction of LH mode at 200 nm even exceeds 50%. Closure analysis is carried out between the HTDMA-measured &#954; and the ACSM-derived hygroscopicity using different approximations for the hygroscopic parameters of organic compounds (&#954;org). The results indicate that &#954;org is less sensitive towards the variation of its oxidation level under HRH conditions but has a stronger O: C-dependency under LRH conditions. The difference in the chemical composition and their corresponding physical properties under different RH/T conditions reflects potentially different formation mechanisms of secondary organic aerosols at those two distinct episodes.

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Effects of Typical Chemical Agents on Preventing Pollution and Controlling Drought in a Cherry Orchard

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.550-553.1340 ◽

2012 ◽

Vol 550-553 ◽

pp. 1340-1344

Author(s):

Ren Kuan Liao ◽

Pei Ling Yang ◽

Shu Mei Ren ◽

Hang Yi ◽

Long Wang ◽

...

Keyword(s):

Water Content ◽

Soil Water ◽

Soil Water Content ◽

North China Plain ◽

North China ◽

Root Zone ◽

Soil Layer ◽

The North ◽

The North China Plain ◽

Chemical Agents

In the North China plain, serious Non-point-source (NPS) pollution and drought are two great concerns in agricultural production. In our studies, two typical chemical agents ( SAP and FA ) were selected to control drought and pollution in a cheery orchard. Soil water content, nutrient transport in soil profile have been researched. The results showed that the soil water content of treatments with chemical agents increased maximally by 19.4% relative to treatment without chemical agents, and increased by 35.2% for Ammonium-N in 20-60 cm soil layer ( main root zone ). However, in 60-120 cm deeper soil layer, the water leakage of treatments with chemical agents decreased averagely by 15.1% relative to treatment without chemical agents, and increased by 43.8% for Nitrate-N. The chemical agents hold water and nutrient in root zone and thus reducing the risk of pollutant leaching into the underground water. It can be found that treatment ( 150kg/h㎡ SAP + 300 times FA ) is the optimal combination group in all treatments. The chemical prevention technology provided a new guide for controlling drought and reducing NPS pollution in cherry planting in the North China plain.

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A study of aerosol liquid water content based on hygroscopicity measurements at high relative humidity in the North China Plain

Atmospheric Chemistry and Physics ◽

10.5194/acp-14-6417-2014 ◽

2014 ◽

Vol 14 (12) ◽

pp. 6417-6426 ◽

Cited By ~ 67

Author(s):

Y. X. Bian ◽

C. S. Zhao ◽

N. Ma ◽

J. Chen ◽

W. Y. Xu

Keyword(s):

Relative Humidity ◽

Water Content ◽

Liquid Water ◽

North China Plain ◽

North China ◽

Liquid Water Content ◽

High Relative Humidity ◽

The North ◽

The North China Plain ◽

Thermodynamic Equilibrium Model

Abstract. Water can be a major component of aerosol particles, also serving as a medium for aqueous-phase reactions. In this study, a novel method is presented to calculate the aerosol liquid water content at high relative humidity based on measurements of aerosol hygroscopic growth factor, particle number size distribution and relative humidity in the Haze in China (HaChi) summer field campaign (July–August 2009) in the North China Plain. The aerosol liquid water content calculated using this method agreed well with that calculated using a thermodynamic equilibrium model (ISORROPIA II) at high relative humidity (>60%) with a correlation coefficient of 0.96. At low relative humidity (<60%), an underestimation was found in the calculated aerosol liquid water content by the thermodynamic equilibrium model. This discrepancy mainly resulted from the ISORROPIA II model, which only considered limited aerosol chemical compositions. The mean and maximum values of aerosol liquid water content during the HaChi campaign reached 1.69 × 10−4 g m−3 and 9.71 × 10−4 g m−3, respectively. A distinct diurnal variation of the aerosol liquid water content was found, with lower values during daytime and higher ones at night. The aerosol liquid water content depended strongly on the relative humidity. The aerosol liquid water content in the accumulation mode dominated the total aerosol liquid water content.

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Quantification of known and unknown terpenoid organosulfates in PM10 using untargeted LC–HRMS/MS: contrasting summertime rural Germany and the North China Plain

Environmental Chemistry ◽

10.1071/en19089 ◽

2019 ◽

Vol 16 (5) ◽

pp. 333 ◽

Cited By ~ 5

Author(s):

Martin Brüggemann ◽

Dominik van Pinxteren ◽

Yuchen Wang ◽

Jian Zhen Yu ◽

Hartmut Herrmann

Keyword(s):

Mass Spectrometry ◽

Particulate Matter ◽

North China Plain ◽

North China ◽

Organic Aerosols ◽

Atmospheric Particulate Matter ◽

Oxidation Products ◽

The North ◽

The North China Plain ◽

Total Concentrations

Environmental contextSecondary organic aerosols account for a major fraction of atmospheric particulate matter, affecting both climate and human health. Organosulfates, abundant compounds in organic aerosols, are difficult to measure because of the lack of authentic standards. Here we quantify terpene-derived organosulfates in atmospheric particulate matter at a rural site in Germany and at the North China Plain using a combined target/non-target high-resolution mass spectrometry approach. AbstractOrganosulfates (OSs) are a ubiquitous class of compounds in atmospheric aerosol particles. However, a detailed quantification of OSs is commonly hampered because of missing authentic standards and the abundance of unknown OSs. Using a combined targeted and untargeted approach of high-resolution liquid chromatography–Orbitrap mass spectrometry (LC–Orbitrap MS), we quantified for the first time the total concentrations of known and unknown monoterpene (MT) and sesquiterpene (SQT) OSs in summertime PM10 particulate matter from field studies in rural Germany (MEL) and the North China Plain (NCP). At each site, we observed more than 50 MT-OSs, 13 of which were detectable at both sites. For both locations, median concentrations of MT-OSs were in the range of 10 to 40ngm−3, to which the 13 common MT-OSs contributed on average >50%. The main contributor to MT-OSs was C9H16O7S (MT-OS 267) with average mass concentrations of 2.23 and 6.38ngm−3 for MEL and NCP respectively. The concentrations of MT-OSs correlated with the concentrations of MT oxidation products only for MEL. For NCP, the low concentrations of MT oxidation products (i.e. typically <1ngm−3) suggested a suppression of carboxylic acid formation under high concentrations of NOx and particulate sulfate. Furthermore, we observed 17 SQT-OSs for the MEL samples, whereas 40 SQT-OSs were detected in the NCP samples. Only five of these SQT-OSs were detectable at both sites. Correspondingly, the total concentrations of SQT-OSs were larger for NCP than for MEL, which suggested large differences in the particle chemistry. In particular, aerosol acidity was found to be a key factor during SQT-OS formation, and was probably not sufficient in the PM10 from MEL.

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Estimation of soil water content and evapotranspiration from irrigated cropland on the North China Plain

Journal of Plant Nutrition and Soil Science ◽

10.1002/jpln.200625179 ◽

2008 ◽

Vol 171 (5) ◽

pp. 751-761 ◽

Cited By ~ 11

Author(s):

Jie Jiang ◽

Yongqiang Zhang ◽

Martin Wegehenkel ◽

Qiang Yu ◽

Jun Xia

Keyword(s):

Water Content ◽

Soil Water ◽

Soil Water Content ◽

North China Plain ◽

North China ◽

The North ◽

The North China Plain

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A~study of aerosol liquid water content based on hygroscopicity measurements at high relative humidity in the North China Plain

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-14-4089-2014 ◽

2014 ◽

Vol 14 (3) ◽

pp. 4089-4118

Author(s):

Y. X. Bian ◽

C. S. Zhao ◽

N. Ma ◽

J. Chen ◽

W. Y. Xu

Keyword(s):

Relative Humidity ◽

Water Content ◽

Liquid Water ◽

North China Plain ◽

North China ◽

Liquid Water Content ◽

High Relative Humidity ◽

The North ◽

The North China Plain ◽

Thermodynamic Equilibrium Model

Abstract. Water can be a major component of an aerosol particle. Also water serves as a medium for aqueous-phase reactions in aerosols. In this study, a novel method is presented to calculate the aerosol liquid water content at high relative humidity based on measurements of aerosol hygroscopic growth factor, particle number size distribution and relative humidity in the Haze in China (HaChi) summer field campaign (July–August 2009) in the North China Plain. The aerosol liquid water content calculated using this method agreed well with that calculated using a thermodynamic equilibrium model (ISORROPIA II) at high relative humidity (>60 %) with a correlation coefficient of 0.9658. At low relative humidity (<60%), an underestimation was found in the calculated aerosol liquid water content by the thermodynamic equilibrium model. This discrepancy mainly resulted from the ISORROPIA II model, which only considered limited aerosol chemical compositions. The mean and maximum values of aerosol liquid water content during the HaChi campaign reached 1.69 × 10−4; g m−3 and 9.71 × 10−4; g m−3, respectively. A distinct diurnal variation of the aerosol liquid water content was found, with lower values during daytime and higher ones at night. The aerosol liquid water content depended strongly on the relative humidity. The aerosol liquid water content in the accumulation mode dominated the total aerosol liquid water content.

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Contribution of hydroxymethanesulfonate (HMS) to severe winter haze in the North China Plain

10.5194/acp-2020-113 ◽

2020 ◽

Author(s):

Tao Ma ◽

Hiroshi Furutani ◽

Fengkui Duan ◽

Takashi Kimoto ◽

Jingkun Jiang ◽

...

Keyword(s):

Ion Chromatography ◽

North China Plain ◽

North China ◽

Molar Ratio ◽

Formation Mechanisms ◽

Aerosol Formation ◽

Severe Winter ◽

The North ◽

The North China Plain ◽

High Concentrations

Abstract. Severe winter hazes accompanied by high concentrations of fine particulate matter (PM2.5) occur frequently in the North China Plain and threaten public health. Organic matter (OM) and sulfate are recognized as major components of PM2.5, while atmospheric models often fail to predict their high concentrations during severe winter hazes due to incomplete understanding of secondary aerosol formation mechanisms. By using a novel combination of single particle mass spectrometer and optimized ion chromatography measurement, here we show that hydroxymethanesulfonate (HMS), formed by the reaction between formaldehyde (HCHO) and dissolved SO2 in aerosol water, is ubiquitous in Beijing winter. The HMS concentration and the molar ratio of HMS to sulfate increased with the deterioration of winter haze. High concentrations of precursors (SO2 and HCHO) coupled with low oxidant levels, low temperature, high relative humidity, and moderately acid pH facilitate the heterogeneous formation of HMS, which could account for up to 15 % of OM in winter haze and lead to 36 % overestimates of sulfate when using traditional ion chromatography measurements. Despite the clean air actions have substantially reduced SO2 emissions, HMS concentration and molar ratio of HMS to sulfate during severe winter hazes increased from 2015 to 2016 with the growth of HCHO concentration. Our findings illustrate the significant contribution of heterogeneous HMS chemistry to severe winter hazes in Beijing, which help to improve the prediction of OM and sulfate, and suggest that the reduction in HCHO can help to mitigate haze pollution.

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Molecular distribution and stable carbon isotopic compositions of dicarboxylic acids and related SOA from biogenic sources in the summertime atmosphere of Mt. Tai in the North China Plain

Atmospheric Chemistry and Physics ◽

10.5194/acp-18-15069-2018 ◽

2018 ◽

Vol 18 (20) ◽

pp. 15069-15086 ◽

Cited By ~ 13

Author(s):

Jingjing Meng ◽

Gehui Wang ◽

Zhanfang Hou ◽

Xiaodi Liu ◽

Benjie Wei ◽

...

Keyword(s):

Azelaic Acid ◽

North China Plain ◽

North China ◽

Organic Aerosols ◽

Dicarboxylic Acids ◽

Stable Carbon ◽

Δ13c Values ◽

Carbon Isotopic ◽

The North ◽

The North China Plain

Abstract. Molecular distributions and stable carbon isotopic (δ13C values) compositions of dicarboxylic acids and related secondary organic aerosols (SOA) in PM2.5 aerosols collected on a day/night basis at the summit of Mt. Tai (1534 m a.s.l.) in the summer of 2016 were analyzed to investigate the sources and photochemical aging process of organic aerosols in the forested highland region of the North China Plain. The molecular distributions of dicarboxylic acids and related SOA are characterized by the dominance of oxalic acid (C2), followed by malonic (C3), succinic (C4) and azelaic (C9) acids. The concentration ratios of C2 ∕ C4, diacid-C ∕ OC and C2 ∕ total diacids are larger in the daytime than in the nighttime, suggesting that the daytime aerosols are more photochemically aged than those in the nighttime due to the higher temperature and stronger solar radiation. Both ratios of C2 ∕ C4 (R2>0.5) and C3 ∕ C4 (R2>0.5) correlated strongly with the ambient temperatures, indicating that SOA in the mountaintop atmosphere are mainly derived from the photochemical oxidation of local emissions rather than long-range transport. The mass ratios of azelaic acid to adipic acid (C9 ∕ C6), azelaic acid to phthalic aid (C9 ∕ Ph) and glyoxal to methylglyoxal (Gly ∕ mGly) and the strong linear correlations of major dicarboxylic acids and related SOA (i.e., C2, C3, C4, ωC2, Pyr, Gly and mGly) with biogenic precursors (SOA tracers derived from isoprene, α/β-pinene and β-caryophyllene) further suggest that aerosols in this region are mainly originated from biogenic sources (i.e., tree emissions). C2 concentrations correlated well with aerosol pH, indicating that particle acidity favors the organic acid formation. The stable carbon isotopic compositions (δ13C) of the dicarboxylic acids are higher in the daytime than in the nighttime, with the highest value (-16.5±1.9 ‰) found for C2 and the lowest value (-25.2±2.7 ‰) found for C9. An increase in δ13C values of C2 along with increases in C2 ∕ Gly and C2 ∕ mGly ratios was observed, largely due to the isotopic fractionation effect during the precursor oxidation process.

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