Variability of the aerosol number size distribution in Beijing, China: New particle formation, dust storms, and high continental background

Wehner, B.; Wiedensohler, Alfred; Tuch, Thomas; Wu, Zhijun; Hu, Min; Slanina, J.; Kiang, C. S.

doi:10.1029/2004gl021596

Cited by 144 publications

(118 citation statements)

References 14 publications

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“…The GR of all the NPF events observed ranged from 0.5 to 9.0 nm h −1 with a mean value of 3.5 nm h −1 . Previous estimates of the GR during NPF using the SMPS have yielded mean values of 1.0 nm h −1 (Wehner et al, 2004) and 1.8 nm h −1 (Wu et al, 2007). Zhibin et al (2013) determined the GRs of a number of NPF events in Beijing over a 4-year period and reported a range of 0.1 to 10 nm h −1 with a mean of 3.0 nm h −1 , which is in close agreement with our value.…”

Section: Particle Growth Ratementioning

confidence: 99%

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Observations of particles at their formation sizes in Beijing, China

Jayaratne

Pushpawela

et al. 2017

Atmos. Chem. Phys.

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Abstract. New particle formation (NPF) has been observed in many highly polluted environments of South East Asia, including Beijing, where the extent of its contribution to intense haze events is still an open question. Estimated characteristics of NPF events, such as their starting times and formation and growth rates of particles, are more accurate when the detection range of particles extends to smaller sizes. In order to understand the very first steps of particle formation, we used a neutral cluster and air ion spectrometer (NAIS) to investigate particle characteristics at sizes exactly at which atmospheric nucleation and cluster activity occurs. Observations over a continuous 3-month period in Beijing showed 26 NPF events. These events generally coincided with periods with relatively clean air when the wind direction was from the less industrialised north. No NPF events were observed when the daily mean PM 2.5 concentration exceeded 43 µg m −3 , which was the upper threshold for particle formation in Beijing. The fraction of particles that are charged in the size range 2-42 nm was normally about 15 %. However, this fraction increased to 20-30 % during haze events and decreased to below 10 % during NPF events. With the NAIS, we very precisely determined the starting times of NPF to a greater accuracy than has been possible in Beijing before and provided a temporal distribution of NPF events with a maximum at about 08:30 LT. Particle formation rates varied between 12 and 38 cm −3 s −1 . Particle growth rates were estimated to be in the range of 0.5-9.0 nm h −1 . These results are more reliable than previous studies in Beijing as the measurements were conducted for the first time at the exact sizes at which clusters form into particles and provide useful insight into the formation of haze events.

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Section: Particle Growth Ratementioning

confidence: 99%

“…The earliest study of NPF using a TSI scanning mobility particle sizer (SMPS) in Beijing was carried out by Wehner et al (2004). They observed NPF on 25 out of 45 days of measurement, and on each of these days the PNC exceeded 10 5 cm −3 .…”

Section: Introductionmentioning

confidence: 99%

Observations of particles at their formation sizes in Beijing, China

Jayaratne

Pushpawela

et al. 2017

Atmos. Chem. Phys.

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“…In the past decades, extensive studies have been conducted to characterize particle number size distributions in Beijing at ground level (Wehner et al, 2004;Yue et al, 2009;Wu et al, 2011;Gao et al, 2012;Wang et al, 2013b). The continuous measurements of aerosol number size distributions from 3 nm to 10 µm within the city area of Beijing in spring indicated a high variability in number concentrations, and the variations were substantially different among dust storm, clean, and polluted periods (Wehner et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Simultaneous measurements of particle number size distributions at ground level and 260 m on a meteorological tower in urban Beijing, China

Zhao

Wang

et al. 2017

Atmos. Chem. Phys.

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Abstract. Despite extensive studies into the characterization of particle number size distributions at ground level, realtime measurements above the urban canopy in the megacity of Beijing have never been performed to date. Here we conducted the first simultaneous measurements of size-resolved particle number concentrations at ground level and 260 m in urban Beijing from 22 August to 30 September. Our results showed overall similar temporal variations in number size distributions between ground level and 260 m, yet periods with significant differences were also observed. Particularly, accumulation-mode particles were highly correlated (r 2 = 0.85) at the two heights, while Aitken-mode particles presented more differences. Detailed analysis suggests that the vertical differences in number concentrations strongly depended on particle size, and particles with a mobility diameter between 100 and 200 nm generally showed higher concentrations at higher altitudes. Particle growth rates and condensation sinks were also calculated, which were 3.2 and 3.6 nm h −1 , and 2.8 × 10 −2 and 2.9 × 10 −2 s −1 , at ground level and 260 m, respectively. By linking particle growth with aerosol composition, we found that organics appeared to play an important role in the early stage of the growth (09:00-12:00 LT) while sulfate was also important during the later period. Positive matrix factorization of size-resolved number concentrations identified three common sources at ground level and 260 m, including a factor associated with new particle formation and growth events (NPEs), and two secondary factors that represent photochemical processing and regional transport. Cooking emission was found to have a large contribution to small particles and showed much higher concentration at ground level than 260 m in the evening. These results imply that investigation of NPEs at ground level in megacities needs to consider the influences of local cooking emissions. The impacts of regional emission controls on particle number concentrations were also illustrated. Our results showed that regional emission controls have a dominant impact on accumulation-mode particles by decreasing gas precursors and particulate matter loadings, and hence suppressing particle growth. In contrast, the influences on Aitken particles were much smaller due to the enhanced new particle formation (NPF) events.

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“…Since these events of new particle formation are observed to take place practically everywhere in the boundary layer, even in the polluted areas (e.g. Harrison et al, 2000;Wehner and Wiedensohler, 2003;Wehner et al, 2005;Alam et al, 2003;Charron et al, 2007), it is probable that several compounds can be potentially participating in the growth, resulting in a variety of aerosol particle compositions. A number of different organic species have been linked with the particle growth process in the natural forest environment (e.g.…”

Section: Introductionmentioning

confidence: 99%

Mode resolved density of atmospheric aerosol particles

et al. 2008

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Abstract. In this study, we investigate the mode resolved density of ultrafine atmospheric particles measured in boreal forest environment. The method used here enables us to find the distinct density information for each mode in atmospheric fine particle population: the density values for nucleation, Aitken, and accumulation mode particles are presented. The experimental data was gained during 2 May

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Variability of the aerosol number size distribution in Beijing, China: New particle formation, dust storms, and high continental background

Cited by 144 publications

References 14 publications

Observations of particles at their formation sizes in Beijing, China

Observations of particles at their formation sizes in Beijing, China

Simultaneous measurements of particle number size distributions at ground level and 260 m on a meteorological tower in urban Beijing, China

Mode resolved density of atmospheric aerosol particles

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Variability of the aerosol number size distribution in Beijing, China: New particle formation, dust storms, and high continental background

Cited by 144 publications

References 14 publications

Observations of particles at their formation sizes in Beijing, China

Observations of particles at their formation sizes in Beijing, China

Simultaneous measurements of particle number size distributions at ground level and 260 m on a meteorological tower in urban Beijing, China

Mode resolved density of atmospheric aerosol particles

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Product

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Simultaneous measurements of particle number size distributions at ground level and 260 m on a meteorological tower in urban Beijing, China