Summertime aerosol volatility measurements in Beijing, China

Xu, Wenbin; Xie, Conghui; Karnezi, Eleni; Zhang, Qi; Wang, Jun Feng; Pandis, Spyros N.; Ge, Xinlei; Wang, Qingqing; Zhao, Jun; Du, Wei; Qiu, Yanmei; Zhou, Wei; He, Ya‐Ling; Zhang, Jingwei; An, Junling; Liu, Ying; Li, Jie; Fu, Pingqing; Wang, Zifa; Worsnop, Douglas R.; Sun, Yele

doi:10.5194/acp-2019-135

Cited by 17 publications

(35 citation statements)

References 51 publications

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“…In particular, whether SOA materials condensed on BC particles have similar chemical characteristics to those externally mixed with BC particles 10 remains poorly understood. Previous observations in urban environments have reported that the mass spectral features of ambient OOA components identified by the PMF analysis were significantly different between the two co-located measurements even though their temporal variabilities strongly correlated to each other (Chen et al, 2018;Lee et al, 2017;Liu et al, 2019;Massoli et al, 2015;Wang et al, 2020;Xu et al, 2019;Zhao et al, 2019). Given our observations that vaporization scheme plays a critical role in the fragmentation process of oxygenated organic species,…”

Section: Insight Into Ambient Ooa Characteristicssupporting

confidence: 63%

“…Figure 3a compares the ambient OOA components determined by the TV and LV schemes (i.e., concurrent HR-ToF-AMS and SP-AMS LV scheme measurements) at the same location if their time series of mass concentrations are strongly correlated (i.e., R > 0.75). Table S1 summaries the characteristics of the OOA components observed in Beijing summer (Xie et al, 2019a;Xu et al, 2019), Beijing winter (Wang et al, 2019;Xie et al, 2019b),…”

Section: Changes In # / # Ratiomentioning

confidence: 99%

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Elemental analysis of Oxygenated Organic Coating on Black Carbon Particles using a Soot-Particle Aerosol Mass Spectrometer

Ma¹,

Rivellini²,

Cui³

et al. 2020

Preprint

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Abstract. Chemical characterization of organic coatings is important to advance our understanding of the physio-chemical properties and environmental fate of black carbon (BC) particles. The soot-particle aerosol mass spectrometer (SP-AMS) has been utilized for this purpose in recent field studies. The laser vaporization (LV) scheme of SP-AMS can heat BC cores gradually until they are completely vaporized, during which organic coatings can be vaporized at temperatures lower than that of the thermal vaporizer (TV) used in a standard high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) that employs flash vaporization. This work investigates the effects of vaporization schemes on fragmentation and elemental analysis of known oxygenated organic species using three SP-AMS instruments. We show that LV can reduce fragmentation of organic molecules. Substantial enhancement of C2H3O+/CO2+ and C2H4O2+ signals was observed for most of the tested species when the LV scheme was used, suggesting that the observational frameworks based using HR-ToF-AMS field data may not be directly applicable for evaluating the chemical evolution of oxygenated organic aerosol (OOA) components coated on ambient BC particles. The uncertainties of H:C and O:C determined by the improved-ambient (I-A) method for both LV and TV approaches were similar, with scaling factors of 1.10 for H:C and 0.89 for O:C were determined to facilitate more direct comparisons between observations from the two vaporization schemes. Furthermore, the I-A method was updated based on the multilinear regression model for the LV scheme measurements. The updated parameters can reduce the relative errors of O:C from −26.3 % to 5.8 %, whereas the relative errors of H:C remain roughly the same. Applying the scaling factors and the updated parameters for the I-A method to ambient data, we found that even though the time series of OOA components determined by the LV and TV schemes are strongly correlated at the same location, OOA coatings were likely less oxygenated compared to those externally mixed with BC.

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Section: Insight Into Ambient Ooa Characteristicssupporting

confidence: 63%

Section: Changes In # / # Ratiomentioning

confidence: 99%

Elemental analysis of Oxygenated Organic Coating on Black Carbon Particles using a Soot-Particle Aerosol Mass Spectrometer

Ma¹,

Rivellini²,

Cui³

et al. 2020

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…At the time of the SARS outbreak, there were no specialized health emergency agencies, established plans, systems, mechanisms, or applicable legal framework. Faced with severe challenges, the Chinese government responded by developing a health emergency system based on a "one plan, three systems" strategy, and continued to strengthen basic health services [9]. "One plan" refers to the emergency plan, and "three systems" refers to establishing and improving (1) emergency response systems, (2) mechanisms, and (3) legal systems.…”

Section: Comprehensive Advancement Of China's Health Emergency Systemmentioning

confidence: 99%

Strengths, Weaknesses, Opportunities and Threats (SWOT) Analysis of China’s Prevention and Control Strategy for the COVID-19 Epidemic

Wang

2020

IJERPH

215

153

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This study used the Strengths (S), Weaknesses (W), Opportunities (O) and Threats (T) (SWOT) analysis method, drawing on our experience of the response to the 2003 SARS epidemic, the 2019 China Health Statistics Yearbook data, and changes in China's policy environment for the pneumonia epidemic response relating to the novel coronavirus (COVID-19) infection, to perform a systematic analysis of the COVID-19 epidemic prevention and control strategy S, W, O, and T, with a further analysis of a strategic foundation and to determine a significant and relative strategy. We assessed and formulated strength-opportunity (SO), weakness-opportunity (WO), strength-threat (ST), and weakness-threat (WT) strategies for the prevention and control of the COVID-19 epidemic. We conducted an in-depth analysis and identified the highest-priority policies. These are: reshaping the emergency system (SO1); adding health emergency departments to universities and other institutions (WO2); adjusting the economic structure and strengthening international and domestic linkages (ST2); and strengthening public intervention in responding to public health emergencies (WT1).

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“…According to the basic theory on transmission of elastic stress wave in continuous medium [18,19], the equations of particle motion are deduced and can be expressed as…”

Section: Relationship Between Velocities Of Seismic Waves and Dynamicmentioning

confidence: 99%

Back Analysis and Calculation of Dynamic Mechanical Parameters of Rock Mass with Measured Blasting Vibration Signals

Yang

Gao

et al. 2018

Mathematical Problems in Engineering

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How to obtain dynamic parameters of rock masses quickly and precisely is a popular and difficult problem, which plays a very important part in engineering design or construction. Currently, the methods used to obtain these parameters are in situ testing method, empirical formula, and so on. However, these methods have some shortcomings, such as large investment and long construction period, which cannot obtain the dynamic parameters precisely and quickly in the engineering scale. In this study, a new method of estimating the rock parameters based on the measured field blasting vibration signals is proposed according to theory of elastic stress wave. In addition, an improved method for S-wave identification used in engineering scale was proposed and then the numerical simulation is given to verify the feasibility. Comparison of the numerical identification results and theoretical results clearly show that the improved method is available in S-wave identification with errors less than 2%. By identifying the arrival times of P and S waves, the propagation velocities of P and S waves are calculated and the parameters of rock mass can be obtained at last. Through analyzing the measured field blasting vibration signals in Fengning pumped-storage power station, the dynamic elastic modulus of rock mass inversed by vibration signals is about 2.2∼2.9 times of its static elastic modulus, while the inversed dynamic Poisson's ratio is 0.9∼0.975 times of the static.

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Summertime aerosol volatility measurements in Beijing, China

Cited by 17 publications

References 51 publications

Elemental analysis of Oxygenated Organic Coating on Black Carbon Particles using a Soot-Particle Aerosol Mass Spectrometer

Elemental analysis of Oxygenated Organic Coating on Black Carbon Particles using a Soot-Particle Aerosol Mass Spectrometer

Strengths, Weaknesses, Opportunities and Threats (SWOT) Analysis of China’s Prevention and Control Strategy for the COVID-19 Epidemic

Back Analysis and Calculation of Dynamic Mechanical Parameters of Rock Mass with Measured Blasting Vibration Signals

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