Particle hygroscopicity and its link to chemical composition in the urban atmosphere of Beijing, China, during summertime
Simultaneous measurements of particle number size distribution, particle hygroscopic properties, and size-resolved chemical composition were made during the summer of 2014 in Beijing, China. During the measurement period, the mean hygroscopicity parameters (<i>κ</i>s) of 50, 100, 150,...
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2016-02-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/16/1123/2016/acp-16-1123-2016.pdf |
| _version_ | 1818139783462912000 |
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| author | Z. J. Wu J. Zheng D. J. Shang Z. F. Du Y. S. Wu L. M. Zeng A. Wiedensohler M. Hu |
| author_facet | Z. J. Wu J. Zheng D. J. Shang Z. F. Du Y. S. Wu L. M. Zeng A. Wiedensohler M. Hu |
| author_sort | Z. J. Wu |
| collection | DOAJ |
| description | Simultaneous measurements of particle number size distribution, particle
hygroscopic properties, and size-resolved chemical composition were made
during the summer of 2014 in Beijing, China. During the measurement period,
the mean hygroscopicity parameters (<i>κ</i>s) of 50, 100, 150, 200, and
250 nm particles were respectively 0.16 ± 0.07, 0.19 ± 0.06,
0.22 ± 0.06, 0.26 ± 0.07, and 0.28 ± 0.10, showing an
increasing trend with increasing particle size. Such size dependency of
particle hygroscopicity was similar to that of the inorganic mass fraction
in PM<sub>1</sub>. The hydrophilic mode (hygroscopic growth factor, HGF > 1.2) was more prominent
in growth factor probability density distributions and its dominance of
hydrophilic mode became more pronounced with increasing particle size. When
PM<sub>2.5</sub> mass concentration was greater than 50 μg m<sup>−3</sup>, the
fractions of the hydrophilic mode for 150, 250, and 350 nm particles
increased towards 1 as PM<sub>2.5</sub> mass concentration increased. This
indicates that aged particles dominated during severe pollution periods in
the atmosphere of Beijing. Particle hygroscopic growth can be well predicted
using high-time-resolution size-resolved chemical composition derived from
aerosol mass spectrometer (AMS) measurements using the Zdanovskii–Stokes–Robinson (ZSR) mixing rule. The organic hygroscopicity
parameter (<i>κ</i><sub>org</sub>) showed a positive correlation with the oxygen to
carbon ratio. During the new particle formation event associated with
strongly active photochemistry, the hygroscopic growth factor or <i>κ</i>
of newly formed particles is greater than for particles with the same sizes
not during new particle formation (NPF) periods. A quick transformation from external mixture to
internal mixture for pre-existing particles (for example, 250 nm particles)
was observed. Such transformations may modify the state of the mixture of
pre-existing particles and thus modify properties such as the light
absorption coefficient and cloud condensation nuclei activation. |
| first_indexed | 2024-12-11T10:33:35Z |
| format | Article |
| id | doaj.art-01ed502826954777bb75ed76a576021f |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-12-11T10:33:35Z |
| publishDate | 2016-02-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-01ed502826954777bb75ed76a576021f2022-12-22T01:10:47ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242016-02-01161123113810.5194/acp-16-1123-2016Particle hygroscopicity and its link to chemical composition in the urban atmosphere of Beijing, China, during summertimeZ. J. Wu0J. Zheng1D. J. Shang2Z. F. Du3Y. S. Wu4L. M. Zeng5A. Wiedensohler6M. Hu7State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, ChinaState Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, ChinaState Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, ChinaState Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, ChinaState Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, ChinaState Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, ChinaLeibniz Institute for Tropospheric Research, 04318 Leipzig, GermanyState Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, ChinaSimultaneous measurements of particle number size distribution, particle hygroscopic properties, and size-resolved chemical composition were made during the summer of 2014 in Beijing, China. During the measurement period, the mean hygroscopicity parameters (<i>κ</i>s) of 50, 100, 150, 200, and 250 nm particles were respectively 0.16 ± 0.07, 0.19 ± 0.06, 0.22 ± 0.06, 0.26 ± 0.07, and 0.28 ± 0.10, showing an increasing trend with increasing particle size. Such size dependency of particle hygroscopicity was similar to that of the inorganic mass fraction in PM<sub>1</sub>. The hydrophilic mode (hygroscopic growth factor, HGF > 1.2) was more prominent in growth factor probability density distributions and its dominance of hydrophilic mode became more pronounced with increasing particle size. When PM<sub>2.5</sub> mass concentration was greater than 50 μg m<sup>−3</sup>, the fractions of the hydrophilic mode for 150, 250, and 350 nm particles increased towards 1 as PM<sub>2.5</sub> mass concentration increased. This indicates that aged particles dominated during severe pollution periods in the atmosphere of Beijing. Particle hygroscopic growth can be well predicted using high-time-resolution size-resolved chemical composition derived from aerosol mass spectrometer (AMS) measurements using the Zdanovskii–Stokes–Robinson (ZSR) mixing rule. The organic hygroscopicity parameter (<i>κ</i><sub>org</sub>) showed a positive correlation with the oxygen to carbon ratio. During the new particle formation event associated with strongly active photochemistry, the hygroscopic growth factor or <i>κ</i> of newly formed particles is greater than for particles with the same sizes not during new particle formation (NPF) periods. A quick transformation from external mixture to internal mixture for pre-existing particles (for example, 250 nm particles) was observed. Such transformations may modify the state of the mixture of pre-existing particles and thus modify properties such as the light absorption coefficient and cloud condensation nuclei activation.https://www.atmos-chem-phys.net/16/1123/2016/acp-16-1123-2016.pdf |
| spellingShingle | Z. J. Wu J. Zheng D. J. Shang Z. F. Du Y. S. Wu L. M. Zeng A. Wiedensohler M. Hu Particle hygroscopicity and its link to chemical composition in the urban atmosphere of Beijing, China, during summertime Atmospheric Chemistry and Physics |
| title | Particle hygroscopicity and its link to chemical composition in the urban atmosphere of Beijing, China, during summertime |
| title_full | Particle hygroscopicity and its link to chemical composition in the urban atmosphere of Beijing, China, during summertime |
| title_fullStr | Particle hygroscopicity and its link to chemical composition in the urban atmosphere of Beijing, China, during summertime |
| title_full_unstemmed | Particle hygroscopicity and its link to chemical composition in the urban atmosphere of Beijing, China, during summertime |
| title_short | Particle hygroscopicity and its link to chemical composition in the urban atmosphere of Beijing, China, during summertime |
| title_sort | particle hygroscopicity and its link to chemical composition in the urban atmosphere of beijing china during summertime |
| url | https://www.atmos-chem-phys.net/16/1123/2016/acp-16-1123-2016.pdf |
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