Size-resolved effective density of urban aerosols in Shanghai

Yin, Zi; Ye, Xingnan; Jiang, Shuqin; Tao, Ye; Yang, Shiguang; Yang, Xin; Chen, Jianmin

doi:10.1016/j.atmosenv.2014.10.055

Cited by 60 publications

(57 citation statements)

References 52 publications

(74 reference statements)

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“…The size dependency of particle effective density varied in the literature. Hu et al (2012) and Yin et al (2015) reported that effective density of the particles increased as particle size increased while a opposite trend was observed by Geller et al (2006) and Spencer et al (2007). The different trends were attributable to the variable fraction of lower-density mode particles (ρ eff < 1.0 g cm −3 ).…”

Section: Ion Chromatographymentioning

confidence: 94%

“…Trace gas pollutants were monitored using Thermo Scientific ™ i-series gas analyzers (43i for SO 2 , 49i for O 3 , 42i for NO/NO 2 /NO x ), and meteorological data were monitored using an automatic meteorological station (model CAWS600, Huayun Inc., China) (Yin et al, 2015). The data of PM 2.5 , PM 10 , and CO were released by the Shanghai Environmental Monitoring Center.…”

Section: Measurements Of Air Quality Index and Ground Meteorologicalmentioning

confidence: 99%

“…In this observation, particle number size distribution in the range of 14-600 nm and hygroscopic growth at 83 % RH for particles with dry diameters of 40, 100, 220, 300, 350, and 400 nm were determined by HTDMA in turn. The determination of effective density by DMA-APM was described pre- viously (Yin et al, 2015;Pagels et al, 2009). Briefly, a combined system consisting of a compact APM (model 3601, Kanomax Inc.) and a CPC (model 3775, TSI Inc.) was connected to the sample tubing through a three-way electrical switch behind the upstream DMA (DMA1).…”

Section: Htdma-apm Systemmentioning

confidence: 99%

“…Effective density has served as a tracer for new particle formation (NPF) and for the aging process in previous studies (Yin et al, 2015;Guo et al, 2014). The ambient particles in urban areas are mostly complex mixtures of elemental carbon (EC), organics (OC), and secondary inorganic aerosols (SIA) .…”

Section: Introductionmentioning

confidence: 99%

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Insight into winter haze formation mechanisms based on aerosol hygroscopicity and effective density measurements

Xie

et al. 2017

Atmos. Chem. Phys.

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Abstract. We characterize a representative particulate matter (PM) episode that occurred in Shanghai during winter 2014. Particle size distribution, hygroscopicity, effective density, and single particle mass spectrometry were determined online, along with offline analysis of water-soluble inorganic ions. The mass ratio of SNA / PM 1.0 (sulfate, nitrate, and ammonium) fluctuated slightly around 0.28, suggesting that both secondary inorganic compounds and carbonaceous aerosols contributed substantially to the haze formation, regardless of pollution level. Nitrate was the most abundant ionic species during hazy periods, indicating that NO x contributed more to haze formation in Shanghai than did SO 2 . During the representative PM episode, the calculated PM was always consistent with the measured PM 1.0 , indicating that the enhanced pollution level was attributable to the elevated number of larger particles. The number fraction of the near-hydrophobic group increased as the PM episode developed, indicating the accumulation of local emissions. Three "banana-shaped" particle evolutions were consistent with the rapid increase of PM 1.0 mass loading, indicating that the rapid size growth by the condensation of condensable materials was responsible for the severe haze formation. Both hygroscopicity and effective density of the particles increased considerably with growing particle size during the bananashaped evolutions, indicating that the secondary transformation of NO x and SO 2 was one of the most important contributors to the particle growth. Our results suggest that the accumulation of gas-phase and particulate pollutants under stagnant meteorological conditions and subsequent rapid particle growth by secondary processes were primarily responsible for the haze pollution in Shanghai during wintertime.

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Section: Ion Chromatographymentioning

confidence: 94%

Section: Measurements Of Air Quality Index and Ground Meteorologicalmentioning

confidence: 99%

Section: Htdma-apm Systemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Insight into winter haze formation mechanisms based on aerosol hygroscopicity and effective density measurements

Xie

et al. 2017

Atmos. Chem. Phys.

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“…The vapours contained by particles failed to reach the maximum limit and were unable to promote the excess moisture to bind particles to form water droplets. That is, a high relative humidity could pose a certain effect on the atmospheric visibility by affecting the moisture content of particulates [34]. If the relative humidity in the air continued to increase beyond the hygroscopic threshold of fine aerosols, then the potential dew could easily be converted into effective dew.…”

Section: Factors Affecting Dew Condensation During Fog-haze Daysmentioning

confidence: 99%

Influence of Fog-Haze on Dew Condensation in Urban Areas

Xu¹,

Zhu

Pan

et al. 2018

Teh. vjesn.

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Abstract:In recent years, fog-haze weather has frequently occurred in urban ecosystem, with accompanied dew condensation in the surface layer. Dew formation plays an important role in air purification, which takes fine aerosols in the atmosphere as the condensation nuclei. However, the influence of fog-haze on dew condensation remains unclear. Thus, this study aims to evaluate the influences of fog-haze days on the frequency, intensity, and duration of dew condensation, to reveal the factors relevant to dew condensation during weather pollution, and to improve the air quality in fog-haze days. The monitor-based direct weighing method was employed in this study to observe the vapour condensation in urban greenbelt under fog-haze and normal weather conditions during the frost-free season (April-October 2017) in Changchun, China. The differences in dew condensation intensity and frequency were discriminated under different weather conditions. Then, the influences of fog-haze days on the vapour condensation were analyzed by monitoring the velocity and duration of dew condensation in polluted weather. Finally, a program for improving air quality was proposed based on the analysis of major meteorological factors that affect the dew condensation during the fog-haze days. Results show that the dew condensation velocity decreases significantly (P < 0.01) from 0.0067 mm/h in normal weather to 0.0026 mm/h in a fog-haze day, whereas the condensation duration is prolonged. The dew condensation intensities are 0.064, 0.045, and 0.051 mm/d under fog, haze, and normal weather conditions, respectively, and the fog-haze weather has no significant effect on the frequency or intensity of dew condensation (P > 0.05). The particulate matter concentration, wind speed, air pressure, relative humidity, and solar radiation are the main factors that affect the vapour transport during the fog-haze days. Artificial increase of surface layer vapours can promote the particulates to absorb vapours fully and settle to the ground in the form of dew, thereby reducing the particulate matter concentration within the scope of human activities. The present study supplements the eigenvalues for dew condensation in urban areas during special pollution periods and reveals the influence of fog-haze on the night time vapour condensation in urban areas. Findings of this study provide theoretical basis for further developing the programs for controlling fog-haze weather and improving urban air quality.

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Effects of amines on particle growth observed in new particle formation events

Tao

Jiang

et al. 2016

JGR Atmospheres

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Particle size distributions in the range of 0.01–10 µm were measured in urban Shanghai in the summer of 2013 using a Wide‐range Particle Spectrometer (WPS). Size‐segregated aerosol samples were collected concurrently using a Micro‐Orifice Uniform Deposit Impactor (MOUDI), which aided our in‐depth understanding of the new particle formation (NPF) mechanism in the polluted Yangtze River Delta area. During the observations, 16 NPF events occurred at high temperatures (~34.7°C) on clear and sunny days. In the ammonium‐poor PM1.0 (particulate matter less than 1.0 µm), sulfate and ammonium accounted for 92% of the total water‐soluble inorganic species. Six aminiums were detected in these MOUDI samples, among which the group of diethylaminium and trimethylaminium (DEAH+ + TMAH+) was the most abundant. The very high level of aminiums (average concentration up to 86.4 ng m−3 in PM1.8), together with highly acidic aerosols, provided insight into the frequent NPF events. The high mass ratio of total aminiums to NH4+ (>0.2 for PM0.056) further highlighted the important role of amines in promoting NPF. The concentration of DEAH+ + TMAH+ in new particles below 180 nm was strongly correlated with aerosol phase acidity, indicating that acid‐base reactions dominated the aminium formation in NPF events. The unexpected enhancement of DEAH+ + TMAH+ on a nonevent day was attributed to the transportation of an SO2 plume. Our results reveal that the heterogeneous uptake of amines is dominated by the acid‐base reaction mechanism, which can effectively contribute to particle growth in NPF events.

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Size-resolved effective density of urban aerosols in Shanghai

Cited by 60 publications

References 52 publications

Insight into winter haze formation mechanisms based on aerosol hygroscopicity and effective density measurements

Insight into winter haze formation mechanisms based on aerosol hygroscopicity and effective density measurements

Influence of Fog-Haze on Dew Condensation in Urban Areas

Effects of amines on particle growth observed in new particle formation events

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