Ambient air - Determination of the particle number size distribution of atmospheric aerosol using a Mobility Particle Size Spectrometer (MPSS)

Abstract. The particle number size distribution is an important parameter to characterize the atmospheric aerosol and its influence on the Earth's climate. Here we describe a new Optical Particle Size Spectrometer (OPSS) for measurements of the accumulation mode particle number size distribution in the tropopause region onboard a passenger aircraft (IAGOS-CARIBIC observatory (In-service Aircraft for a Global Observing System – Civil Aircraft for Regular Investigation of the Atmosphere Based on an Instrument Container)). A modified "KS93 particle sensor" from RION Co., Ltd. together with a new airflow system and a dedicated data acquisition system are the key components of the CARIBIC OPSS. The instrument records individual particle pulses in the particle size range 130–1110 nm diameter (for a particle refractive index of 1.47-i0.006 for an upper tropospheric (UT) aerosol particle) and thus allows the post-flight choice of the time resolution and the size distribution bin width. The CARIBIC OPSS has a 50 % particle detection diameter of 152 nm and a maximum asymptotic counting efficiency of 98 %. The instruments measurement performance shows no pressure dependency and no coincidence for free tropospheric conditions. The size response function of the CARIBIC OPSS was obtained by a polystyrene latex calibration in combination with model calculations. Particle number size distributions measured with the new OPSS in the lowermost stratosphere agreed within a factor of two in concentration with balloon-borne measurements over western North America. Since June 2010 the CARIBIC OPSS is deployed once per month in the IAGOS-CARIBIC observatory.

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A fast and easy-to-implement inversion algorithm for mobility particle size spectrometers considering particle number size distribution information outside of the detection range

Atmospheric Measurement Techniques ◽

10.5194/amt-7-95-2014 ◽

2014 ◽

Vol 7 (1) ◽

pp. 95-105 ◽

Cited By ~ 34

Author(s):

S. Pfeifer ◽

W. Birmili ◽

A. Schladitz ◽

T. Müller ◽

A. Nowak ◽

...

Keyword(s):

Particle Size ◽

Size Distribution ◽

Particle Number ◽

Inversion Algorithm ◽

Charge Inversion ◽

Final Particle ◽

Detection Range ◽

Number Size Distribution ◽

Particle Number Size Distribution ◽

Multiple Charge

Abstract. Multiple-charge inversion is an essential procedure to convert the raw mobility distributions recorded by mobility particle size spectrometers, such as the DMPS or SMPS (differential or scanning mobility particle sizers), into true particle number size distributions. In this work, we present a fast and easy-to-implement multiple-charge inversion algorithm with sufficient precision for atmospheric conditions, but extended functionality. The algorithm can incorporate size distribution information from sensors that measure beyond the upper sizing limit of the mobility spectrometer, such as an aerodynamic particle sizer (APS) or an optical particle counter (OPC). This feature can considerably improve the multiple-charge inversion result in the upper size range of the mobility spectrometer, for example, when substantial numbers of coarse particles are present. The program also yields a continuous size distribution from both sensors as an output. The algorithm is able to calculate the propagation of measurement errors, such as those based on counting statistics, into on the final particle number size distribution. As an additional aspect, the algorithm can perform all inversion steps under the assumption of non-spherical particle shape, including constant or size-dependent shape factors.

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An optical particle size spectrometer for aircraft-borne measurements in IAGOS-CARIBIC

Atmospheric Measurement Techniques ◽

10.5194/amt-9-2179-2016 ◽

2016 ◽

Vol 9 (5) ◽

pp. 2179-2194 ◽

Cited By ~ 8

Author(s):

Markus Hermann ◽

Andreas Weigelt ◽

Denise Assmann ◽

Sascha Pfeifer ◽

Thomas Müller ◽

...

Keyword(s):

Particle Size ◽

Size Distribution ◽

Particle Number ◽

Pulse Signal ◽

Counting Efficiency ◽

Polystyrene Latex ◽

Particle Size Range ◽

Model Calculations ◽

Number Size Distribution ◽

Particle Number Size Distribution

Abstract. The particle number size distribution is an important parameter to characterize the atmospheric aerosol and its influence on the Earth's climate. Here we describe a new optical particle size spectrometer (OPSS) for measurements of the accumulation mode particle number size distribution in the tropopause region on board a passenger aircraft (IAGOS-CARIBIC observatory: In-service Aircraft for a Global Observing System – Civil Aircraft for Regular Investigation of the Atmosphere Based on an Instrument Container). A modified KS93 particle sensor from RION Co., Ltd., together with a new airflow system and a dedicated data acquisition system, is the key component of the CARIBIC OPSS. The instrument records individual particle pulse signal curves in the particle size range 130–1110 nm diameter (for a particle refractive index of 1.47-i0.006) together with a time stamp and thus allows the post-flight choice of the time resolution and the size distribution bin width. The CARIBIC OPSS has a 50 % particle detection diameter of 152 nm and a maximum asymptotic counting efficiency of 98 %. The instrument's measurement performance shows no pressure dependency and no particle coincidence for free tropospheric conditions. The size response function of the CARIBIC OPSS was obtained by a polystyrene latex calibration in combination with model calculations. Particle number size distributions measured with the new OPSS in the lowermost stratosphere agreed within a factor of 2 in concentration with balloon-borne measurements over western North America. Since June 2010 the CARIBIC OPSS is deployed once per month in the IAGOS-CARIBIC observatory.

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Intercomparison of 15 aerodynamic particle size spectrometers (APS 3321): uncertainties in particle sizing and number size distribution

Atmospheric Measurement Techniques Discussions ◽

10.5194/amtd-8-11513-2015 ◽

2015 ◽

Vol 8 (11) ◽

pp. 11513-11532 ◽

Cited By ~ 1

Author(s):

S. Pfeifer ◽

T. Müller ◽

K. Weinhold ◽

N. Zikova ◽

S. Santos ◽

...

Keyword(s):

Particle Size ◽

Quality Assurance ◽

Size Distribution ◽

Particle Number ◽

Particle Sizing ◽

Aerodynamic Diameter ◽

Atmospheric Measurements ◽

Number Size Distribution ◽

Aerodynamic Particle Size ◽

Particle Number Size Distribution

Abstract. Aerodynamic particle size spectrometers are a well-established method to measure number size distributions of coarse mode particles in the atmosphere. Quality assurance is essential for atmospheric observational aerosol networks to obtain comparable results with known uncertainties. In a laboratory study within the framework of ACTRIS (Aerosols, Clouds, and Trace gases Research Infrastructure Network), 15 aerodynamic particle size spectrometers (APS model 3321, TSI Inc., St. Paul, MN, USA) were compared with a focus on flow rates accuracy, particle sizing, and unit-to-unit variability of the particle number size distribution. Flow rate deviations were relatively small (within a few percent), while the sizing accuracy was found to be within 10 % compared to polystyrene latex (PSL) reference particles. The unit-to-unit variability in terms of the particle number size distribution during this study was within 10–20 % for particles in the range of 0.9 up to 3 μm, which is acceptable for atmospheric measurements. For particles smaller than that, the variability increased up to 60 %, probably caused by differences in the counting efficiencies of individual units. Number size distribution data for particles smaller than 0.9 μm in aerodynamic diameter should be only used with caution. For particles larger than 3 μm, the unit-to-unit variability increased as well. A possible reason is an insufficient sizing accuracy in combination with a steeply sloping particle number size distribution and the increasing uncertainty due to decreasing counting. This uncertainty of the particle number size distribution has especially to be considered if higher moments of the size distribution such as the particle volume or mass are calculated, which require the conversion of the aerodynamic diameter measured to a volume equivalent diameter. In order to perform a quantitative quality assurance, a traceable reference method for the particle number concentration in the size range 0.5–3 μm is needed.

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Intercomparison of 15 aerodynamic particle size spectrometers (APS 3321): uncertainties in particle sizing and number size distribution

Atmospheric Measurement Techniques ◽

10.5194/amt-9-1545-2016 ◽

2016 ◽

Vol 9 (4) ◽

pp. 1545-1551 ◽

Cited By ~ 14

Author(s):

Sascha Pfeifer ◽

Thomas Müller ◽

Kay Weinhold ◽

Nadezda Zikova ◽

Sebastiao Martins dos Santos ◽

...

Keyword(s):

Particle Size ◽

Quality Assurance ◽

Size Distribution ◽

Particle Number ◽

Particle Sizing ◽

Aerodynamic Diameter ◽

Atmospheric Measurements ◽

Number Size Distribution ◽

Aerodynamic Particle Size ◽

Particle Number Size Distribution

Abstract. Aerodynamic particle size spectrometers are a well-established method to measure number size distributions of coarse mode particles in the atmosphere. Quality assurance is essential for atmospheric observational aerosol networks to obtain comparable results with known uncertainties. In a laboratory study within the framework of ACTRIS (Aerosols, Clouds, and Trace gases Research Infrastructure Network), 15 aerodynamic particle size spectrometers (APS model 3321, TSI Inc., St. Paul, MN, USA) were compared with a focus on flow rates, particle sizing, and the unit-to-unit variability of the particle number size distribution. Flow rate deviations were relatively small (within a few percent), while the sizing accuracy was found to be within 10 % compared to polystyrene latex (PSL) reference particles. The unit-to-unit variability in terms of the particle number size distribution during this study was within 10 % to 20 % for particles in the range of 0.9 up to 3 µm, which is acceptable for atmospheric measurements. For particles smaller than that, the variability increased up to 60 %, probably caused by differences in the counting efficiencies of individual units. Number size distribution data for particles smaller than 0.9 µm in aerodynamic diameter should only be used with caution. For particles larger than 3 µm, the unit-to-unit variability increased as well. A possible reason is an insufficient sizing accuracy in combination with a steeply sloping particle number size distribution and the increasing uncertainty due to decreasing counting. Particularly this uncertainty of the particle number size distribution must be considered if higher moments of the size distribution such as the particle volume or mass are calculated, which require the conversion of the aerodynamic diameter measured to a volume equivalent diameter. In order to perform a quantitative quality assurance, a traceable reference method for the particle number concentration in the size range 0.5–3 µm is needed.

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Diesel Particle Size Distribution: The Conversion Of Particle Number Size Distribution To Mass Distribution

10.4271/2001-01-1946 ◽

2001 ◽

Cited By ~ 10

Author(s):

G. E. Andrews ◽

A. G. Clarke ◽

N. Y. Rojas ◽

T. Sale ◽

D. Gregory

Keyword(s):

Particle Size ◽

Particle Size Distribution ◽

Size Distribution ◽

Mass Distribution ◽

Particle Number ◽

Number Size Distribution ◽

Particle Number Size Distribution

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Particle number size distribution measurements of PM1 and PM10 in fogs and implications on fog droplet evolutions

10.5194/egusphere-egu2020-8156 ◽

2020 ◽

Author(s):

Jiangchuan Tao ◽

Nan Ma ◽

Yanyan Zhang ◽

Ye Kuang ◽

Juan Hong ◽

...

Keyword(s):

Particle Size ◽

Size Distribution ◽

Particle Number ◽

Critical Diameter ◽

Number Concentration ◽

Hygroscopic Growth ◽

Number Size Distribution ◽

Significant Difference ◽

Activation Ratio ◽

Particle Number Size Distribution

CCN number concentration (NCCN), particle size-resolved activation ratio at supersaturation (SS) of 0.10% and particle number size distribution (PNSD) in dry state of both ambient PM1 and PM10 particles were measured in the North China Plain in November in 2018. Two fog events were observed during nighttime of 12nd and 13rd Nov. During fog events, the dry particle concentrations sampled from the PM10 inlet were much higher than those from PM1 inlet for particles (particle size bins) with diameter larger than ~200 nm. Additional sub-micron particles sampled by PM10 inlet but not been sampled by PM1 inlet indicates that these particles have grown into droplets with diameter larger than 1um. The growth of particle size by over 5 times can be resulted from not only the activation to form fog droplets but also the hygroscopic growth at RH higher than 99%. There was no significant decrease of particle number concentration larger than ~200 nm during fog periods compared with those beyond the fog periods, suggesting that the fog droplets may be generally smaller than 10um and can be sampled by PM10 inlet. The size-resolved activation ratio curve showed that the critical diameter was about 160-180nm and there was significant difference (>50%) of NCCN at SS of 0.1% between PM1 and PM10, mainly due to the difference of PNSD between PM1 and PM10 in fogs. The measured PNSD and CCN-activity might be applied on the analysis of the relationship between fog droplets and the corresponding ambient supersaturations.

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