Observations of particles at their formation sizes in Beijing, China

Jayaratne, Rohan; Pushpawela, B. G.; He, Congrong; Lĭ, Hui; Gao, Jian; Chai, Fahe; Morawska, Lidia

doi:10.5194/acp-17-8825-2017

Cited by 36 publications

(31 citation statements)

References 34 publications

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“…For the other 2 events, it was 49.8 and 40.5 µg m −3 , respectively. In another campaign in Beijing during January 2016 (Jayaratne et al, 2017), 14 NPF events were observed. Among them, 12 events occurred when the daily-average PM 2.5 mass concentration was lower than 30 µg m −3 .…”

Section: Predicting Npf Days Using Pm 25 Mass Concentrationmentioning

confidence: 99%

Aerosol surface area concentration: a governing factor in new particle formation in Beijing

Cai¹,

Yang²,

Fu³

et al. 2017

Atmos. Chem. Phys.

103

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Abstract. The predominating role of aerosol Fuchs surface area, A Fuchs , in determining the occurrence of new particle formation (NPF) events in Beijing was elucidated in this study. The analysis was based on a field campaign from 12 March to 6 April 2016 in Beijing, during which aerosol size distributions down to ∼ 1 nm and sulfuric acid concentrations were simultaneously monitored. The 26 days were classified into 11 typical NPF days, 2 undefined days, and 13 non-event days. A dimensionless factor, L , characterized by the relative ratio of the coagulation scavenging rate over the condensational growth rate (Kuang et al., 2010), was applied in this work to reveal the governing factors for NPF events in Beijing. The three parameters determining L are sulfuric acid concentration, the growth enhancement factor characterized by contribution of other gaseous precursors to particle growth, , and A Fuchs . Different from other atmospheric environments, such as in Boulder and Hyytiälä, the dailymaximum sulfuric acid concentration and in Beijing varied in a narrow range with geometric standard deviations of 1.40 and 1.31, respectively. A positive correlation between the estimated new particle formation rate, J 1.5 , and sulfuric acid concentration was found with a mean fitted exponent of 2.4. However, the maximum sulfuric acid concentrations on NPF days were not significantly higher (even lower, sometimes) than those on non-event days, indicating that the abundance of sulfuric acid in Beijing was high enough to initiate nucleation, but may not necessarily lead to NPF events. Instead, A Fuchs in Beijing varied greatly among days with a geometric standard deviation of 2.56, whereas the variabilities of A Fuchs in Tecamac, Atlanta, and Boulder were reported to be much smaller. In addition, there was a good correlation between A Fuchs and L in Beijing (R 2 = 0.88). Therefore, it was A Fuchs that fundamentally determined the occurrence of NPF events. Among 11 observed NPF events, 10 events occurred when A Fuchs was smaller than 200 µm 2 cm −3 . NPF events were suppressed due to the coagulation scavenging when A Fuchs was greater than 200 µm 2 cm −3 . Measured A Fuchs in Beijing had a good correlation with its PM 2.5 mass concentration (R 2 = 0.85) since A Fuchs in Beijing was mainly determined by particles in the size range of 50-500 nm that also contribute to the PM 2.5 mass concentration.

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Section: Predicting Npf Days Using Pm 25 Mass Concentrationmentioning

confidence: 99%

Aerosol surface area concentration: a governing factor in new particle formation in Beijing

Cai¹,

Yang²,

Fu³

et al. 2017

Atmos. Chem. Phys.

103

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show abstract

“…In this study, a neutral cluster and air ion spectrometer (NAIS), which could detect particle size distribution down than 3 nm, was used. The NAIS greatly avoided the misleading interference of primary emission, and it measured more accurate particle formation sizes (Jayaratne et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Investigation of new particle formation at the summit of Mt. Tai, China

Lv¹,

Sui²,

Chen³

et al. 2018

Atmos. Chem. Phys.

Self Cite

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Abstract. To date, few comprehensive field observations of new particle formation (NPF) have been carried out at mountaintop sites in China. In this study, simultaneous measurements of particle size distribution, trace gases, meteorological parameters, and mass concentration and chemical composition of PM 2.5 were performed at the summit of Mt. Tai (1534 m a.s.l.) from 25 July to 24 August 2014 (Phase I), 21 September to 9 December 2014 (Phase II), and 16 June to 7 August 2015 (Phase III) to investigate characteristics and favorable conditions of NPF in a relatively clean mountaintop environment. The NPF events were identified based on particle size distribution measured by the neutral cluster and air ion spectrometer (NAIS), and 66 such events were observed during a period of 164 days -corresponding to an occurrence frequency of 40 %. The formation rates of 3 nm particles (J 3 ) and growth rates were in the ranges of 0.82-25.04 cm −3 s −1 and 0.58-7.76 nm h −1 , respectively. On average, the condensation sink (CS), O 3 concentration, air temperature, and relative humidity were lower, whereas the SO 2 concentration was higher on NPF days than that on non-NPF days. The CS on Mt. Tai was at a low level and lower CS was critical for NPF. NPF events were common when wind came from the east-southeast and west-southwest, which was probably associated with relatively lower CS in the east-southeast and higher SO 2 concentration in the west-southwest. O 3 was not a governing factor for NPF in this study, and a high level of NO x concentration might be responsible for the decreased O 3 concentration on NPF days. Three categories of backward trajectories were classified, among which the continental air mass was the majority. The continental air mass passing through more polluted areas (denoted as Type I) favored NPF because of enhanced SO 2 concentration and potential ammonia with it. An in-depth analysis of SO 2 indicated that sulfuric acid was a dominant precursor on Mt. Tai; meanwhile, biogenic organics released from ambient forests in warm seasons and anthropogenic volatile organic compounds emitted from domestic heating in cold seasons also promoted NPF.

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“…found that the Fuchs surface area (which is a representative parameter of coagulation scavenging based on kinetic theory and is proportional to CS) fundamentally determined the occurrence of NPF events. The Fuchs surface 10 area had a good correlation with the PM2.5 mass concentration, and no NPF event was observed when the daily mean PM2.5 concentration was higher than 43 μg m -3 in the winter of 2015 in Beijing (Jayaratne et al, 2017). However, in some cases, the CS or the average coagulation sinks during NPF events were not significantly lower compare to other times when new particles were not formed, indicating that other factors, such as the precursor vapors and photochemical activity, might also play an important role in driving NPF (Gong et al, 2010).…”

Section: Npf Frequencymentioning

confidence: 96%

“…Many studies about NPF in China measured only particles larger than 10 nm, while a few studies also measured particles with diameters in the range of 3-10 nm. However, the information of particles smaller than 3 nm is quite limited due to the lack of detection 15 instruments, and only few studies reported measurement results of sub-3 nanoparticles (Xiao et al, 2015;Jayaratne et al, 2017). As for gas phase precursors, direct measurements of H2SO4 were carried out with atmospheric pressure-ion drift-chemical ionization mass spectrometer (AP-ID-CIMS) in a few studies (Yue et al, 2010;Zheng et al, 2011;Wang et al, 2011), while other studies usually estimated H2SO4 concentrations using different proxies related to SO2, radiation, O3, and relative humidity (RH).…”

Section: Overview Of Npf Research In Chinamentioning

confidence: 99%

“…The NPF event frequency can be quite different in air masses from different directions (Wu et al, 2007). Higher NPF event frequencies were usually observed within relatively clean air masses having a low CS (Zhu et al, 2013;An et al, 2015;Jayaratne et al, 2017;Peng et al, 2017). However, in some cases, NPF events also occurred in polluted air masses.…”

Section: Npf Frequencymentioning

confidence: 99%

See 1 more Smart Citation

Atmospheric new particle formation in China

Chu¹,

Kerminen²,

Bianchi³

et al. 2018

Preprint

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New particle formation (NPF) studies in China were summarized comprehensively in this paper. NPF frequency, formation rate and particle growth rate were closely compared among the observations carried out at different types of sites in different regions of China in different seasons, with the aim of exploring the nucleation and particle growth mechanisms. The interactions between air pollution and NPF are discussed, emphasizing on the properties of NPF under heavy pollution 10 conditions. The current understanding of NPF cannot not be fully explain the frequent occurrence of NPF at high aerosol loadings in China, and possible reasons for this phenomenon are proposed. The effects of NPF and some aspects of NPF research requiring further investigations are also summarized in this paper.

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Observations of particles at their formation sizes in Beijing, China

Cited by 36 publications

References 34 publications

Aerosol surface area concentration: a governing factor in new particle formation in Beijing

Aerosol surface area concentration: a governing factor in new particle formation in Beijing

Investigation of new particle formation at the summit of Mt. Tai, China

Atmospheric new particle formation in China

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