Aerosol size distribution estimation and associated uncertainty for measurement with a Scanning Mobility Particle Sizer (SMPS)

Abstract. A quality-controlled, 5-year dataset of aerosol number size distributions (particles with diameters (Dp) from 7 nm through 14 µm) was developed using observations from a scanning mobility particle sizer, aerodynamic particle sizer, and a condensation particle counter at the Department of Energy's Southern Great Plains (SGP) site. This dataset was used for two purposes. First, typical characteristics of the aerosol size distribution (number, surface area, and volume) were calculated for the SGP site, both for the entire dataset and on a seasonal basis, and size distribution lognormal fit parameters are provided. While the median size distributions generally had similar shapes (four lognormal modes) in all the seasons, there were some significant differences between seasons. These differences were most significant in the smallest particles (Dp<30 nm) and largest particles (Dp>800 nm). Second, power spectral analysis was conducted on this long-term dataset to determine key temporal cycles of total aerosol concentrations, as well as aerosol concentrations in specified size ranges. The strongest cyclic signal was associated with a diurnal cycle in total aerosol number concentrations that was driven by the number concentrations of the smallest particles (Dp<30 nm). This diurnal cycle in the smallest particles occurred in all seasons in ∼50 % of the observations, suggesting a persistent influence of new particle formation events on the number concentrations observed at the SGP site. This finding is in contrast with earlier studies that suggest new particle formation is observed primarily in the springtime at this site. The timing of peak concentrations associated with this diurnal cycle was shifted by several hours depending on the season, which was consistent with seasonal differences in insolation and boundary layer processes. Significant diurnal cycles in number concentrations were also found for particles with Dp between 140 and 800 nm, with peak concentrations occurring in the overnight hours, which were primarily associated with both nitrate and organic aerosol cycles. Weaker cyclic signals were observed for longer timescales (days to weeks) and are hypothesized to be related to the timescales of synoptic weather variability. The strongest periodic signals (3.5–5 and 7 d cycles) for these longer timescales varied depending on the season, with no cyclic signals and the lowest variability in the summer.

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Quantifying aerosol size distributions and their temporal variability in the Southern Great Plains, USA

10.5194/acp-2019-131 ◽

2019 ◽

Author(s):

Peter J. Marinescu ◽

Ezra J. T. Levin ◽

Don Collins ◽

Sonia M. Kreidenweis ◽

Susan C. van den Heever

Keyword(s):

Size Distribution ◽

Great Plains ◽

Power Spectral Analysis ◽

Aerosol Size Distribution ◽

Size Distributions ◽

Scanning Mobility Particle Sizer ◽

Condensation Particle Counter ◽

Southern Great Plains ◽

Power Spectral ◽

Particle Sizer

Abstract. A quality-controlled, 5-year dataset (2009–2013) of aerosol number size distributions (particles with diameters (Dp) from 7 nm through 14 μm) was developed using observations from a scanning mobility particle sizer, aerodynamic particle sizer, and a condensation particle counter at the Department of Energy's Southern Great Plains (SGP) site. This dataset was used for two purposes. First, typical characteristics of the aerosol size distribution (number, surface area, and volume) were calculated for the SGP site, both for the entire dataset and on a seasonal basis, and size distribution lognormal fit parameters are provided. While the median size distributions generally had similar shapes (4 lognormal modes) in all the seasons, there were some significant differences between seasons. These differences were most significant in the smallest particles (Dp 800 nm). Second, power spectral analysis was conducted on this long-term dataset to determine key temporal cycles of total aerosol concentrations, as well as aerosol concentrations in specified size ranges. The strongest cyclic signal was associated with a diurnal cycle in total aerosol number concentrations that was driven by the number concentrations of the smallest particles (Dp

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Measurement of nonvolatile particle number size distribution

Atmospheric Measurement Techniques ◽

10.5194/amt-9-103-2016 ◽

2016 ◽

Vol 9 (1) ◽

pp. 103-114 ◽

Cited By ~ 14

Author(s):

G. I. Gkatzelis ◽

D. K. Papanastasiou ◽

K. Florou ◽

C. Kaltsonoudis ◽

E. Louvaris ◽

...

Keyword(s):

Size Distribution ◽

Black Carbon ◽

Biomass Burning ◽

Particle Number ◽

Number Concentration ◽

Experimental Methodology ◽

Particle Number Concentration ◽

Scanning Mobility Particle Sizer ◽

Number Size Distribution ◽

Particle Sizer

Abstract. An experimental methodology was developed to measure the nonvolatile particle number concentration using a thermodenuder (TD). The TD was coupled with a high-resolution time-of-flight aerosol mass spectrometer, measuring the chemical composition and mass size distribution of the submicrometer aerosol and a scanning mobility particle sizer (SMPS) that provided the number size distribution of the aerosol in the range from 10 to 500 nm. The method was evaluated with a set of smog chamber experiments and achieved almost complete evaporation (> 98 %) of secondary organic as well as freshly nucleated particles, using a TD temperature of 400 °C and a centerline residence time of 15 s. This experimental approach was applied in a winter field campaign in Athens and provided a direct measurement of number concentration and size distribution for particles emitted from major pollution sources. During periods in which the contribution of biomass burning sources was dominant, more than 80 % of particle number concentration remained after passing through the thermodenuder, suggesting that nearly all biomass burning particles had a nonvolatile core. These remaining particles consisted mostly of black carbon (60 % mass contribution) and organic aerosol (OA; 40 %). Organics that had not evaporated through the TD were mostly biomass burning OA (BBOA) and oxygenated OA (OOA) as determined from AMS source apportionment analysis. For periods during which traffic contribution was dominant 50–60 % of the particles had a nonvolatile core while the rest evaporated at 400 °C. The remaining particle mass consisted mostly of black carbon with an 80 % contribution, while OA was responsible for another 15–20 %. Organics were mostly hydrocarbon-like OA (HOA) and OOA. These results suggest that even at 400 °C some fraction of the OA does not evaporate from particles emitted from common combustion processes, such as biomass burning and car engines, indicating that a fraction of this type of OA is of extremely low volatility.

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Neural network modelling to estimate particle size distribution based on other particle sections and meteorological parameters

10.5194/amt-2021-37 ◽

2021 ◽

Author(s):

Pak Lun Fung ◽

Martha Arbayani Zaidan ◽

Ola Surakhi ◽

Sasu Tarkoma ◽

Tuukka Petäjä ◽

...

Keyword(s):

Neural Network ◽

Particle Size ◽

Particle Size Distribution ◽

Size Distribution ◽

Meteorological Parameters ◽

Aerosol Size Distribution ◽

Sufficient Information ◽

Electrical Mobility ◽

Particle Sizer ◽

Mass Concentrations

Abstract. In air quality research, often only particle mass concentrations as indicators of aerosol particles are considered. However, the mass concentrations do not provide sufficient information to convey the full story of fractionated size distribution, which are able to deposit differently on respiratory system and cause various harm. Aerosol size distribution measurements rely on a variety of techniques to classify the aerosol size and measure the size distribution. From the raw data the ambient size distribution is determined utilising a suite of inversion algorithms. However, the inversion problem is quite often ill-posed and challenging to invert. Due to the instrumental insufficiency and inversion limitations, models for fractionated particle size distribution are of great significance to fill the missing gaps or negative values. The study at hand involves a merged particle size distribution, from a scanning mobility particle sizer (NanoSMPS) and an optical particle sizer (OPS) covering the aerosol size distributions from 0.01 to 0.42 μm (electrical mobility equivalent size) and 0.3 μm to 10 μm (optical equivalent size) and meteorological parameters collected at an urban background region in Amman, Jordan in the period of 1st Aug 2016–31st July 2017. We develop and evaluate feed-forward neural network (FFNN) models to estimate number concentrations at particular size bin with (1) meteorological parameters, (2) number concentration at other size bins, and (3) both of the above as input variables. Two layers with 10–15 neurons are found to be the optimal option. Lower model performance is observed at the lower edge (0.01

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Laboratory Measurements of the Size Distribution and Activation Ratio of Synthetic Ice Nuclei

10.5194/egusphere-egu2020-3722 ◽

2020 ◽

Author(s):

David Delene ◽

Eli Peske ◽

Mascha Rauscher ◽

Werner Lubitz

Keyword(s):

Size Distribution ◽

Cloud Condensation Nuclei ◽

Scanning Mobility Particle Sizer ◽

Condensation Particle Counter ◽

Ice Nuclei ◽

Aerosol Generator ◽

Condensation Nucleation ◽

Activation Ratio ◽

Particle Sizer ◽

Measured Size Distribution

<p>Laboratory measurement of the particle size distribution and cloud condensation nucleation activation ratio are conducted using two types of synthetic ice nuclei (IN). New Engineered Organic Nuclei (NEON) are fabricated by fermentation and so-called E-lysis of Gram-negative bacteria, which are havested via centrifugation and resuspended in a NaHCO<sub>3</sub> buffer (pH of ~7.8) for final inactivation of lysis escape muntants. NEON is inactivated using 1.25 % (final concentration) glutaraldehyde (GA) and stored in a deep freezer. The NEON with GA solution is atomized using a Sparging Liquid Aerosol Generator (SLAG), which does not sheer or impact the aerosols. The measured size distribution is compared to aerosols produced by the TSI Atmomizer (Model 3076), which impacts generated droplets. The size distribution is measured using a TSI Scanning Mobility Particle Sizer Spectrometer (SMPS) and a TSI Aerodynamic Particle Sizer. A DMT Cloud Condensation Nuclei Counter (CCNC) operated at 0.6 % supersaturation and a TSI Condensation Particle Counter (CPC) is used to measure the activation ratio, which is important to determine effectiveness of the NEON as an immersion ice nuclei. The NEON results are compared to IN produced by burning silver iodine cloud seeding flares.</p>

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