Secondary Formation of Aerosols Under Typical High‐Humidity Conditions in Wintertime Sichuan Basin, China: A Contrast to the North China Plain

2021 ◽  
Vol 126 (10) ◽  
Author(s):  
Yujue Wang ◽  
Min Hu ◽  
Wei Hu ◽  
Jing Zheng ◽  
Hongya Niu ◽  
...  
Keyword(s):  
Sichuan Basin ◽  
North China Plain ◽  
North China ◽  
High Humidity ◽  
The North ◽  
The North China Plain ◽  
Secondary Formation

scholarly journals Analysis of a winter regional haze event and its formation mechanism in the North China Plain

2013 ◽  
Vol 13 (11) ◽  
pp. 5685-5696 ◽  
Author(s):  
X. J. Zhao ◽  
P. S. Zhao ◽  
J. Xu ◽  
W. Meng, ◽  
W. W. Pu ◽  
...  
Keyword(s):  
North China Plain ◽  
North China ◽  
The Other ◽  
Plain Area ◽  
The North ◽  
The North China Plain ◽  
Secondary Formation ◽  
Regional Haze ◽  
Haze Episode ◽  
Haze Days

Abstract. A regional haze episode occurred in the Beijing, Tianjin and Hebei province (BTH) area in the North China Plain (NCP) from 16 to 19 January 2010. Data were collected and analyzed during the time frame of 14 through 23 January 2010 to include the haze event. The increase of secondary inorganic pollutants (SO42−, NO3−, NH4+) in PM2.5 was observed simultaneously at four sites, especially in the plain area of the BTH, which could be identified as a common characteristic of pollution haze in east China. The sulfate and nitrate in PM2.5 were mainly formed through the heterogeneous reaction process in the urban area. The organic matter (OM) increased more significantly at the Chengde (CD) site than the other three sites in the plain area. The secondary organic aerosols only existed during haze days at CD but in both haze and non-haze days at the other three sites, which suggested the greater regional impact of secondary formation process during the haze episode. The secondary formation of aerosol was one important formation mechanism of haze. The strong temperature inversion and descending air motions in the planetary boundary layer (PBL) allowed pollutants to accumulate in a shallow layer. The weak surface wind speed produced high pollutants concentration within source regions. The accumulation of pollutants was one main factor in the haze formation. The enhanced southwest wind in the last period of this episode transported pollutants to the downwind area and expanded the regional scope of the haze.

scholarly journals Measurement report: On the difference of aerosol hygroscopicity between high and low RH conditions in the North China Plain

2022 ◽  
Author(s):  
Jingnan Shi ◽  
Juan Hong ◽  
Nan Ma ◽  
Qingwei Luo ◽  
Yao He ◽  
...  
Keyword(s):  
Chemical Composition ◽  
North China Plain ◽  
North China ◽  
Rural Site ◽  
Formation Processes ◽  
The North ◽  
The North China Plain ◽  
Secondary Formation ◽  
Primary Emissions ◽  
Aerosol Hygroscopicity

Abstract. Atmospheric processes, including both primary emissions and secondary formation, may exert complex effects on aerosol hygroscopicity, which is of significant importance in understanding and quantifying the effect of aerosols on climate and human health. In order to explore the influence of local emissions and secondary formation processes on aerosol hygroscopicity, we investigated the hygroscopic properties of submicron aerosol particles at a rural site in the North China Plain (NCP) in winter 2018. This was conducted by simultaneous measurements of aerosol hygroscopicity and chemical composition, using a self-assembled hygroscopic tandem differential mobility analyzer (HTDMA) and a capture-vaporizer time-of-flight aerosol chemical speciation monitor (CV-ToF-ACSM). The hygroscopicity results showed that the particles during the entire campaign were mainly externally mixed, with a more hygroscopic (MH) mode and a less hygroscopic (LH) particles mode. The mean hygroscopicity parameter values (κmean) derived from hygroscopicity measurements for particles at 60, 100, 150, and 200 nm were 0.16, 0.18, 0.16, and 0.15, respectively. During this study, we classified two distinct episodes with different RH/T conditions, indicative of different primary emissions and secondary formation processes. It was observed that aerosols at all measured sizes were more hygroscopic under the high RH (HRH) episode than those under the low RH (LRH) episode. During the LRH, κ decreased with increasing particle size, which may be explained by the enhanced domestic heating at low temperature, causing large emissions of non- or less-hygroscopic primary aerosols. This is particularly obvious for 200 nm particles, with a dominant number fraction (> 50 %) of LH mode particles. Using O : C-dependent hygroscopic parameters of secondary organic compounds (κSOA), closure analysis between the HTDMA_measured κ and the ACSM_derived κ was carried out. The results showed that κSOA under the LRH episode was less sensitive to the changes in organic oxidation level, while κSOA under the HRH had a relatively stronger dependency on the organic O : C. This feature suggests that the different sources and aerosol evolution processes, partly resulting from the variation in atmospheric RH/T conditions, may lead to significant changes in aerosol chemical composition, which will further influence their corresponding physical properties.

Multiphase chemistry experiment in Fogs and Aerosols in the North China Plain (McFAN): integrated analysis and intensive winter campaign 2018

2021 ◽  
Author(s):  
Guo Li ◽  
Hang Su ◽  
Uwe Kuhn ◽  
Guangjie Zheng ◽  
Ulrich Pöschl ◽  
...  
Keyword(s):  
North China Plain ◽  
North China ◽  
Chem Phys ◽  
High Humidity ◽  
The North ◽  
The North China Plain ◽  
Low Humidity ◽  
Haze Formation ◽  
Chemistry Experiment

<p>In the recent decade, frequently occurring severe haze events in the North China Plain (NCP) have triggered numerous studies on the underlying formation mechanisms, and the contribution of multiphase chemistry on haze formation becomes one of the focal points. The Multiphase chemistry experiment in Fogs and Aerosols in the North China Plain (McFAN) investigated the physicochemical mechanisms leading to haze formation with a focus on the contributions of multiphase processes in aerosols and fogs. We integrated observations on multiple platforms with regional and box model simulations to identify and characterize the key oxidation processes producing sulfate, nitrate and secondary organic aerosols. An outdoor twin-chamber system was deployed to conduct kinetic experiments under real atmospheric conditions in comparison to literature kinetic data from laboratory studies. The experiments were spanning multiple years since 2017 and an intensive field campaign was performed in the winter of 2018. The location of the site minimizes fast transition between clean and polluted air masses, and regimes representative for the North China Plain were observed at the measurement location in Gucheng near Beijing. The consecutive multi-year experiments document recent trends of PM<sub>2.5 </sub>pollution and corresponding changes of aerosol physical and chemical properties, enabling in-depth investigations of established and newly proposed chemical mechanisms of haze formation. This study is mainly focusing on the data obtained from the winter campaign 2018. To investigate multiphase chemistry, the results are presented and discussed by means of three characteristic cases: low humidity, high humidity and fog. We find a strong relative humidity dependence of aerosol chemical compositions, suggesting an important role of multiphase chemistry. Compared with the low humidity period, both PM<sub>1</sub> and PM<sub>2.5 </sub>show higher mass fraction of secondary inorganic aerosols (SIA, mainly as nitrate, sulfate and ammonium) and secondary organic aerosols (SOA) during high humidity and fog episodes. The changes in aerosol composition further influence aerosol physical properties, e.g., with higher aerosol hygroscopicity parameter k and single scattering albedo SSA under high humidity and fog cases. The campaign-averaged aerosol pH is 5.1 ± 0.9, of which the variation is mainly driven by the aerosol water content (AWC) concentrations. Overall, the McFAN experiment provides new evidence of the key role of multiphase reactions in regulating aerosol chemical composition and physical properties in polluted regions.</p><p>References:</p><ul><li>Y. Cheng, et al., <em>Sci. Adv.</em>, 2016, 2, e1601530.</li> <li>G. J. Zheng, et al., <em>Atmos. Chem. Phys.</em>, 2015, 15, 2969-2983.</li> <li>W. Tao, et al., <em>Atmos. Chem. Phys.</em>, 2020, 20, 11729-11746.</li> <li>H. Su, et al., <em>Acc. Chem. Res.</em>, 53, 2034-2043.</li> <li>G. Zheng, et al., <em>Science</em>, 2020, 369, 1374-377.</li> <li>G. Li, et al., <em>Faraday Discussions</em>, 2021, DOI: 10.1039/D0FD00099J.</li> </ul>

scholarly journals Source Identification of Trace Elements in PM2.5 at a Rural Site in the North China Plain

Atmosphere ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 179 ◽  
Author(s):  
Lei Liu ◽  
Yusi Liu ◽  
Wei Wen ◽  
Linlin Liang ◽  
Xin Ma ◽  
...  
Keyword(s):  
North China Plain ◽  
North China ◽  
Shanxi Province ◽  
Rural Site ◽  
The North ◽  
The North China Plain ◽  
Secondary Formation ◽  
Trace Metal Elements ◽  
Range Transport ◽  
Fluorescence Spectrometer

An intensive sampling of PM2.5 was conducted at a rural site (Gucheng) in the North China Plain from 22 October to 23 November 2016. A total of 25 elements (Al, Na, Cl, Mg, P, S, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Sr, Cd, Ba, Pb, and Sb) from PM2.5 filter samples collected daily were measured using a wavelength dispersive X-ray fluorescence spectrometer. Cl, S, and K were the most abundant elements, with average concentrations of 2077.66 ng m−3 (range 118.88–4638.96 ng m−3), 1748.78 ng m−3 (range 276.67–4335.59 ng m−3), and 1287.07 ng m−3 (range 254.90–2748.63 ng m−3), respectively. Among noncrustal trace metal elements, the concentration of Zn was the highest, with an average of 397.74 ng m−3 (range 36.45–1602.96 ng m−3), followed by Sb and Pb, on average, of 299.20 ng m−3 and 184.52 ng m−3, respectively. The morphologies of PM2.5 samples were observed using scanning electron microscopy. The shape of the particles was predominantly spherical, chain-like, and irregular. Positive matrix factorization analysis revealed that soil dust, following by industry, secondary formation, vehicle emissions, biomass and waste burning, and coal combustion, were the main sources of PM2.5. The results of cluster, potential source contribution function, and concentration weighted trajectory analyses suggested that local emissions from Hebei Province, as well as regional transport from Beijing, Tianjin, Shandong, and Shanxi Province, and long-range transport from Inner Mongolia, were the main contributors to PM2.5 pollution.

ROx Budgets and O3 Formation during Summertime at Xianghe Suburban Site in the North China Plain

2021 ◽  
Author(s):  
Min Xue ◽  
Jianzhong Ma ◽  
Guiqian Tang ◽  
Shengrui Tong ◽  
Bo Hu ◽  
...  
Keyword(s):  
North China Plain ◽  
North China ◽  
The North ◽  
The North China Plain ◽  
Suburban Site
Sign in / Sign up

Export Citation Format

Share Document