Bipolar charge distribution of a soft X-ray diffusion charger

Tigges, L.; Wiedensohler, Alfred; Weinhold, Kay; Gandhi, Jeyanthi; Schmid, Hans‐Joachim

doi:10.1016/j.jaerosci.2015.07.002

Cited by 40 publications

(24 citation statements)

References 19 publications

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“…The measurements shown in Figure 14 originate from an ECAC workshop in which a new TSI MPSS was calibrated. The bipolar charge equilibrium of Tigges et al (2015) was used for the soft X-ray charger in the inversion routine. As shown in Figure 14a, the PNSD of the candidate (soft-X-ray) is within the C/¡10% target uncertainty compared to the PNSD of the reference MPSS (Kr 85 ).…”

Section: Soft X-raymentioning

confidence: 99%

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Mobility particle size spectrometers: Calibration procedures and measurement uncertainties

Wiedensohler

Wiesner

Weinhold

et al. 2017

Aerosol Science and Technology

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134

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Mobility particle size spectrometers (MPSS) belong to the essential instruments in aerosol science that determine the particle number size distribution (PNSD) in the submicrometer size range. Following calibration procedures and target uncertainties against standards and reference instruments are suggested for a complete MPSS quality assurance program: (a) calibration of the CPC counting efficiency curve (within 5% for the plateau counting efficiency; within 1 nm for the 50% detection efficiency diameter), (b) sizing calibration of the MPSS, using a certified polystyrene latex (PSL) particle size standard at 203 nm (within 3%), (c) intercomparison of the PNSD of the MPSS (within 10% and 20% of the dN/dlogDP concentration for the particle size range 20-200 and 200-800 nm, respectively), and (d) intercomparison of the integral PNC of the MPSS (within 10%). Furthermore, following measurement uncertainties have been investigated: (a) PSL particle size standards in the range from 100 to 500 nm match within 1% after sizing calibration at 203 nm. (b) Bipolar diffusion chargers based on the radioactive nuclides Kr 85 , Am 241 , and Ni 63 and a new ionizer based on corona discharge follow the recommended bipolar charge distribution, while soft X-ray-based charges may alter faster than expected. (c) The use of a positive high voltage supply show a 10% better performance than a negative one. (d) The intercomparison of the integral PNC of an MPSS against the total number concentration is still within the target uncertainty at an ambient pressure of approximately 500 hPa.

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Section: Soft X-raymentioning

confidence: 99%

“…The ionizer uses positive and negative ions produced by corona discharge, resulting in a bipolar charge distribution similar to ISO 15900, according to the manufacturer. The bipolar charging by soft X-rays produces a different bipolar charge distribution, which was determined and parameterized by Tigges et al (2015).…”

Section: Introductionmentioning

confidence: 99%

Mobility particle size spectrometers: Calibration procedures and measurement uncertainties

Wiedensohler

Wiesner

Weinhold

et al. 2017

Aerosol Science and Technology

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134

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“…BC radiative effects are highly sensitive to the emitted BC particle size distribution (Matsui et al, 2018). The health impacts of BC are significantly related to the BCMSD (Turner et al, 2015). Furthermore, the information of BCMSD can help to study the source, the evolution and the mixing state of ambient BC aerosols (Yu et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Role of black carbon mass size distribution in the direct aerosol radiative forcing

et al. 2019

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Large uncertainties exist when estimating radiative effects of ambient black carbon (BC) aerosol. Previous studies about the BC aerosol radiative forcing mainly focus on the BC aerosols' mass concentrations and mixing states, while the effects of BC mass size distribution (BCMSD) were not well considered. In this paper, we developed a method of measuring the BCMSD by using a differential mobility analyzer in tandem with an Aethalometer. A comprehensive method of multiple charging corrections was proposed and implemented in measuring the BCMSD. Good agreement was obtained between the BC mass concentration integrated from this system and that measured in the bulk phase, demonstrating the reliability of our proposed method. Characteristics of the BCMSD and corresponding radiative effects were studied based on a field measurement campaign conducted in the North China Plain by using our own measurement system. Results showed that the BCMSD had two modes and the mean peak diameters of the modes were 150 and 503 nm. The BCMSD of the coarser mode varied significantly under different pollution conditions with peak diameter varying between 430 and 580 nm, which gave rise to significant variation in aerosol bulk optical properties. The direct aerosol radiative forcing was estimated to vary by 8.45 % for different measured BCMSDs of the coarser mode, which shared the same magnitude with the variation associated with assuming different aerosol mixing states (10.5 %). Our study reveals that the BCMSD as well as its mixing state in estimating the direct aerosol radiative forcing matters. Knowledge of the BCMSD should be fully considered in climate models.

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“…All classification methods that are charge dependent suffer from multiple charging issues (jqj > 1) and this is especially true for the DMA and APM. Prior to classification by these instruments, the aerosol stream is passed through a charge neutralizer ( Ã N in Figure 2) to impart a known bipolar charge distribution to the particles (Wiedensohler and Fissan 1988;Tigges et al 2015). The q of particles exiting the charge neutralizer is a strong function of particle size, shape (Rogak, Flagan, and Nguyen 1993), neutralizer age and type (Tigges et al 2015), and to a lesser extent particle morphology (Covert, Wiedensohler, and Russell 1997).…”

Section: Multiple Chargingmentioning

confidence: 99%

Comparison of three essential sub-micrometer aerosol measurements: Mass, size and shape

Yao

Asa-Awuku

Zangmeister

et al. 2020

Aerosol Science and Technology

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An instrumental trifecta now exists for aerosol separation and classification by aerodynamic diameter (D ae), mobility diameter (D m) and mass (m) utilizing an aerodynamic aerosol classifier (AAC), differential mobility analyzer (DMA) and aerosol particle mass analyzer (APM), respectively. In principle, any combination of two measurements yields the third. These quantities also allow for the derivation of the particle effective density (q eff) and dynamic shape factor (v). Measured and/or derived deviations between tandem measurements are dependent upon the configuration but are generally <10%. Notably, nonphysical values of v (<1) and q eff (>bulk) were determined by the AAC-APM. Harmonization of the results requires the use of v in the determination of m and D m from the AAC-DMA and AAC-APM requiring either a priori assumptions or determination from another method. Further errors can arise from assuming instead of measuring physical conditionse.g., temperature and pressure affect the gas viscosity, mean free path and the Cunningham slip correction factor therefore impacting D m and D aebut are expected to have a smaller impact than v. Utilizing this triplet of instrumentation in combination allows for quantitative determination of v and the particle density (q p). If the bulk density is known or assumed, then the packing density can be determined. The v and q p were determined to be 1.10 ± 0.03 and (1.00 ± 0.02) g cm À3 , respectively, for a water stabilized black carbon mimic that resembles aged (collapsed) soot in the atmosphere. Assuming q bulk ¼ 1.8 g cm À3 , a packing density of 0.55 ± 0.02 is obtained.

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Bipolar charge distribution of a soft X-ray diffusion charger

Cited by 40 publications

References 19 publications

Mobility particle size spectrometers: Calibration procedures and measurement uncertainties

Mobility particle size spectrometers: Calibration procedures and measurement uncertainties

Role of black carbon mass size distribution in the direct aerosol radiative forcing

Comparison of three essential sub-micrometer aerosol measurements: Mass, size and shape

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