Organic acids contribute to rainwater acidity at a rural site in eastern China

2018 ◽  
Vol 11 (4) ◽  
pp. 459-469 ◽  
Author(s):  
Yuwen Niu ◽  
Xinling Li ◽  
Jingjiao Pu ◽  
Zhen Huang
Keyword(s):  
Organic Acids ◽  
Eastern China ◽  
Rural Site ◽  
Rainwater Acidity

Diurnal variations and source apportionment of ozone at the summit of Mount Huang, a rural site in Eastern China

2020 ◽  
Author(s):  
Jinhui Gao
Keyword(s):  
Boundary Layer ◽  
Diurnal Variation ◽  
Source Apportionment ◽  
Southern China ◽  
Eastern China ◽  
Vertical Mixing ◽  
Diurnal Variations ◽  
Rural Site ◽  
Positive Contribution ◽  
Negative Contribution

<p>Comprehensive measurements were conducted at the summit of Mount (Mt.) Huang, a rural site located in eastern China during the summer of 2011. They observed that ozone showed pronounced diurnal variations with high concentrations at night and low values during daytime. The Weather Research and Forecasting with Chemistry (WRF-Chem) model was applied to simulate the ozone concentrations at Mt. Huang in June 2011. With processes analysis and online ozone tagging method we coupled into the model system, the causes of this diurnal pattern and the contributions from different source regions were investigated. Our results showed that boundary layer diurnal cycle played an important role in driving the ozone diurnal variation. Further analysis showed that the negative contribution of vertical mixing was significant, resulting in the ozone decrease during the daytime. In contrast, ozone increased at night owing to the significant positive contribution of advection. This shifting of major factor between vertical mixing and advection formed this diurnal variation. Ozone source apportionment results indicated that approximately half was provided by inflow effect of ozone from outside the model domain (O<sub>3-INFLOW</sub>) and the other half was formed by ozone precursors (O<sub>3-PBL</sub>) emitted in eastern, central, and southern China. In the O<sub>3-PBL</sub>, 3.0% of the ozone was from Mt. Huang reflecting the small local contribution (O<sub>3-LOC</sub>) and the non-local contributions (O<sub>3-NLOC</sub>) accounted for 41.6%, in which ozone from the southerly regions contributed significantly, for example, 9.9% of the ozone originating from Jiangxi, representing the highest geographical contributor. Because the origin and variation of O<sub>3-NLOC</sub> was highly related to the diurnal movements in boundary layer, the similar diurnal patterns between O<sub>3-NLOC</sub> and total ozone both indicated the direct influence of O<sub>3-NLOC</sub> and the importance of boundary layer diurnal variations in the formation of such distinct diurnal ozone variations at Mt. Huang.</p>

scholarly journals Source contributions to ambient VOCs and CO at a rural site in eastern China

2004 ◽  
Vol 38 (27) ◽  
pp. 4551-4560 ◽  
Author(s):  
H Guo ◽  
T Wang ◽  
I.J Simpson ◽  
D.R Blake ◽  
X.M Yu ◽  
...  
Keyword(s):  
Eastern China ◽  
Rural Site ◽  
Source Contributions

Atmospheric gaseous organic acids in winter in a rural site of the North China Plain

2022 ◽  
Vol 113 ◽  
pp. 190-203
Author(s):  
Xiaoyu Hu ◽  
Gan Yang ◽  
Yiliang Liu ◽  
Yiqun Lu ◽  
Yuwei Wang ◽  
...  
Keyword(s):  
Organic Acids ◽  
North China Plain ◽  
North China ◽  
Rural Site ◽  
The North ◽  
The North China Plain

scholarly journals Nitrogen isotope fractionation during gas-particle conversion of NO<sub>x</sub> to NO<sub>3</sub><sup>−</sup> in the atmosphere – implications for isotope-based NO<sub>x</sub> source apportionment

2018 ◽  
Author(s):  
Yunhua Chang ◽  
Yanlin Zhang ◽  
Chongguo Tian ◽  
Shichun Zhang ◽  
Xiaoyan Ma ◽  
...  
Keyword(s):  
Source Apportionment ◽  
Isotope Effect ◽  
Biomass Burning ◽  
Coal Combustion ◽  
Isotope Fractionation ◽  
Road Traffic ◽  
Eastern China ◽  
Rural Site ◽  
Urban Site ◽  
Exchange Reactions

Abstract. Atmospheric fine-particle (PM2.5) pollution is frequently associated with the formation of particulate nitrate (pNO3−), the end product of the oxidation of NOx gases (= NO + NO2) in the upper troposphere. The application of stable nitrogen (N) (and oxygen) isotope analyses of pNO3− to constrain NOx source partitioning in the atmosphere requires the knowledge of the isotope fractionation during the reactions leading to NO3− formation. Here we determined the δ15N values of fresh pNO3− (δ15N-pNO3−) in PM2.5 at a rural site in Northern China, where atmospheric pNO3− can be attributed exclusively to biomass burning. The observed δ15N-pNO3− (12.17 ± 1.55 ‰; n = 8) was much higher than the N isotopic source signature of NOx from biomass burning (1.04 ± 4.13 ‰). The large difference between δ15N-pNO3− and δ15N-NOx (Δ(δ15N)) can be reconciled by the net N isotope effect (ԑN) associated with the gas-particle conversion from NOx to NO3−. For the biomass-burning site, a mean ԑN (≈ Δ(δ15N)) of 10.99 ± 0.74 ‰ was assessed through a newly-developed computational quantum chemistry (CQC) module. ԑN depends on the relative importance of the two dominant N isotope exchange reactions involved (NO2 reaction with OH versus hydrolysis of dinitrogen pentoxide (N2O5) with H2O), and varies between regions, and on a diurnal basis. A second, slightly higher CQC-based mean value for ԑN (15.33 ± 4.90 ‰) was estimated for an urban site with intense traffic in Eastern China, and integrated in a Bayesian isotope mixing model to make isotope-based source apportionment estimates for NOx at this site. Based on the δ15N values (10.93 ± 3.32 ‰, n = 43) of ambient pNO3− determined for the urban site, and considering the location-specific estimate for ԑN, our results reveal that the relative contribution of coal combustion and road traffic to urban NOx are 32 ± 11 % and 68 ± 11 %, respectively. This finding agrees well with a regional bottom-up emission inventory of NOx. Moreover, the variation pattern of OH contribution to ambient pNO3− formation calculated by the CQC module is consistent with that simulated by the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem), further confirming the robustness of our estimates. Our investigations also show that, without the consideration of the N isotope effect during pNO3− formation, the observed δ15N-pNO3− at the study site would erroneously imply that NOx is derived almost entirely from coal combustion. Similarly, reanalysis of reported δ15N-NO3− data throughout China suggests that, nationwide, NOx emissions from coal combustion may be substantively overestimated (by > 30 %) when the N isotope fractionation during atmospheric pNO3− formation is neglected.

scholarly journals Real-time measurements of gas-phase organic acids using SF<sub>6</sub><sup>−</sup> chemical ionization mass spectrometry

2018 ◽  
Vol 11 (9) ◽  
pp. 5087-5104 ◽  
Author(s):  
Theodora Nah ◽  
Yi Ji ◽  
David J. Tanner ◽  
Hongyu Guo ◽  
Amy P. Sullivan ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Organic Acids ◽  
Organic Acid ◽  
Real Time ◽  
Gas Phase ◽  
Chemical Ionization ◽  
Ionization Mass Spectrometry ◽  
Chemical Ionization Mass Spectrometry ◽  
Rural Site ◽  
Ionization Mass

Abstract. The sources and atmospheric chemistry of gas-phase organic acids are currently poorly understood, due in part to the limited range of measurement techniques available. In this work, we evaluated the use of SF6- as a sensitive and selective chemical ionization reagent ion for real-time measurements of gas-phase organic acids. Field measurements are made using chemical ionization mass spectrometry (CIMS) at a rural site in Yorkville, Georgia, from September to October 2016 to investigate the capability of this measurement technique. Our measurements demonstrate that SF6- can be used to measure a range of organic acids in the atmosphere. One-hour averaged ambient concentrations of organic acids ranged from a few parts per trillion by volume (ppt) to several parts per billion by volume (ppb). All the organic acids displayed similar strong diurnal behaviors, reaching maximum concentrations between 17:00 and 19:00 EDT. The organic acid concentrations are dependent on ambient temperature, with higher organic acid concentrations being measured during warmer periods.

scholarly journals Significant increase of surface ozone at a rural site, north of eastern China

2016 ◽  
Vol 16 (6) ◽  
pp. 3969-3977 ◽  
Author(s):  
Zhiqiang Ma ◽  
Jing Xu ◽  
Weijun Quan ◽  
Ziyin Zhang ◽  
Weili Lin ◽  
...  
Keyword(s):  
Control Strategies ◽  
Average Rate ◽  
Surface Ozone ◽  
Eastern China ◽  
Rural Site ◽  
Filter Method ◽  
Ozone Pollution ◽  
The North ◽  
Emission Changes

Abstract. Ozone pollution in eastern China has become one of the top environmental issues. Quantifying the temporal trend of surface ozone helps to assess the impacts of the anthropogenic precursor reductions and the likely effects of emission control strategies implemented. In this paper, ozone data collected at the Shangdianzi (SDZ) regional atmospheric background station from 2003 to 2015 are presented and analyzed to obtain the variation in the trend of surface ozone in the most polluted region of China, north of eastern China or the North China Plain. A modified Kolmogorov–Zurbenko (KZ) filter method was performed on the maximum daily average 8 h (MDA8) concentrations of ozone to separate the contributions of different factors from the variation of surface ozone and remove the influence of meteorological fluctuations on surface ozone. Results reveal that the short-term, seasonal and long-term components of ozone account for 36.4, 57.6 and 2.2 % of the total variance, respectively. The long-term trend indicates that the MDA8 has undergone a significant increase in the period of 2003–2015, with an average rate of 1.13 ± 0.01 ppb year−1 (R2 = 0.92). It is found that meteorological factors did not significantly influence the long-term variation of ozone and the increase may be completely attributed to changes in emissions. Furthermore, there is no significant correlation between the long-term O3 and NO2 trends. This study suggests that emission changes in VOCs might have played a more important role in the observed increase of surface ozone at SDZ.

scholarly journals Particulate organic nitrates in eastern China: variation characteristics and effects of anthropogenic activities

2019 ◽  
Author(s):  
Jun Zhang ◽  
Xinfeng Wang ◽  
Rui Li ◽  
Shuwei Dong ◽  
Yingnan Zhang ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Biomass Burning ◽  
Coal Combustion ◽  
Urban Areas ◽  
Anthropogenic Activities ◽  
Eastern China ◽  
Rural Site ◽  
Organic Nitrate ◽  
Organic Nitrates ◽  
Variation Characteristics

Abstract. Particulate organic nitrates (PONs) constitute a substantial fraction of secondary organic aerosols and have important effects on the reactive nitrogen budget and air quality. Laboratory studies have revealed the non-negligible influence of the interactions between anthropogenic pollutants and biogenic volatile organic compounds (BVOCs) on the formation of PONs. In this study, the contents of specific PONs, including monoterpene hydroxyl nitrate (MHN215), pinene keto nitrate (PKN229), limonene di-keto nitrate (LDKN247), oleic acid keto nitrate (OAKN359), oleic acid hydroxyl nitrate (OAHN361), and pinene sulfate organic nitrate (PSON295), in fine particulate matters at four rural and urban sites in eastern China were determined, and the variation characteristics of PONs and the impacts of human activities on PONs formation were investigated. The average concentration of PONs ranged from 116 to 548 ng m−3 at these four sites. PONs were present in higher levels in summer than in other seasons, owing to the high emissions of precursors and intensive photochemical activities in this hottest season. Among the six species of PONs, MHN215 was dominant. In addition, the proportion of OAKN359 in PONs in urban areas was much higher than that in the rural site, indicating that OAKN359 primarily originated from anthropogenic activities. Slight diurnal differences existed in the concentration and secondary formation of specific PONs and varied with locations, seasons, and precursor VOCs. The measurement results showed that PONs in North China were clearly influenced by coal combustion and biomass burning, while meteorological conditions and biogenic emissions were the dominant contributing factors in the South China. Biomass burning significantly enhanced the formation of PONs due to the elevated concentrations of ozone and the released BVOCs. Sulfur dioxide (SO2) emitted from coal combustion was able to react rapidly with Criegee intermediates, the reaction products of BVOCs with ozone, to produce PONs at high rates, suggesting that there is a substantially greater role played by SO2 in organic nitrate chemistry than has previously been assumed.

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