Effect of Coating Thickness on Particle Bounce in Inertial Impactors

Pak, Steven S.; Liu, Benjamin Y. H.; Rubow, Kenneth L.

doi:10.1080/02786829208959544

Cited by 79 publications

(52 citation statements)

References 16 publications

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“…Bounce-off can be counteracted by the use of a coating of the impaction surface. Pak et al (1992) showed that a coating of Apiezon-L grease needs to be more than 9 µm thick to obtain close to 100 % impactor collection efficiency for solid particles, whereas silicon oil shows more promising properties with rather high efficiency at 0.3 µm thickness. However, applying such a thickness would result in a factor of 2.5 thicker sampling substrate causing typically a factor 1.6 worse PIXE detection limits (if contamination in the coating process can be avoided).…”

Section: Aerosol Sampling and Analysismentioning

confidence: 99%

Comparison between CARIBIC Aerosol Samples Analysed by Accelerator-Based Methods and Optical Particle Counter Measurements

et al. 2014

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Abstract. Inter-comparison of results from two kinds of aerosol systems in the CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on a Instrument Container) passenger aircraft based observatory, operating during intercontinental flights at 9-12 km altitude, is presented. Aerosol from the lowermost stratosphere (LMS), the extra-tropical upper troposphere (UT) and the tropical mid troposphere (MT) were investigated. Aerosol particle volume concentration measured with an optical particle counter (OPC) is compared with analytical results of the sum of masses of all major and several minor constituents from aerosol samples collected with an impactor. Analyses were undertaken with the following accelerator-based methods: particle-induced X-ray emission (PIXE) and particle elastic scattering analysis (PESA). Data from 48 flights during 1 year are used, leading to a total of 106 individual comparisons. The ratios of the particle volume from the OPC and the total mass from the analyses were in 84 % within a relatively narrow interval. Data points outside this interval are connected with inlet-related effects in clouds, large variability in aerosol composition, particle size distribution effects and some cases of non-ideal sampling. Overall, the comparison of these two CARIBIC measurements based on vastly different methods show good agreement, implying that the chemical and size information can be combined in studies of the MT/UT/LMS aerosol.

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Section: Aerosol Sampling and Analysismentioning

confidence: 99%

Comparison between CARIBIC Aerosol Samples Analysed by Accelerator-Based Methods and Optical Particle Counter Measurements

et al. 2014

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“…The MOUDI collecting carbonaceous material was operated without rotating the impactor stages, as a multi-orifice impactor (MOI). OC concentrations measured by the carbon analyzer are converted to organic mass (OM) multiplying by a factor of 1.8 to account for the hydrogen, oxygen, sulfur and nitrogen associated with the organic compounds (Turpin and Lim, 2001 Particle bounce-off in cascade impactors has been documented by several authors, particles as small as 0.2 mm can bounce from their respective collection stage and are collected on stages corresponding to smaller sizes (Hinds, 1998;Pak et al, 1992). This problem is more common in the upper stages of the impactors.…”

Section: Methodsmentioning

confidence: 99%

Mass size distributions and size resolved chemical composition of fine particulate matter at the Pittsburgh supersite

Cabada

Rees

Takahama

et al. 2004

Atmospheric Environment

165

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Size-resolved aerosol mass and chemical composition were measured during the Pittsburgh Air Quality Study. Daily samples were collected for 12 months from July 2001 to June 2002. Micro-orifice uniform deposit impactors (MOUDIs) were used to collect aerosol samples of fine particulate matter smaller than 10 mm. Measurements of PM 0.056 , PM 0.10 , PM 0.18 , PM 0.32 , PM 0.56 , PM 1.0 , PM 1.8 and PM 2.5 with the MOUDI are available for the full study period. Seasonal variations in the concentrations are observed for all size cuts. Higher concentrations are observed during the summer and lower during the winter.Comparison between the PM 2.5 measurements by the MOUDI and other integrated PM samplers reveals good agreement. Good correlation is observed for PM 10 between the MOUDI and an integrated sampler but the MOUDI underestimates PM 10 by 20%. Bouncing of particles from higher stages of the MOUDI (>PM 2.5 ) is not a major problem because of the low concentrations of coarse particles in the area. The main cause of coarse particle losses appears to be losses to the wall of the MOUDI.Samples were collected on aluminum foils for analysis of carbonaceous material and on Teflon filters for analysis of particle mass and inorganic anions and cations. Daily samples were analyzed during the summer (July 2001) and the winter intensives (January 2002). During the summer around 50% of the organic material is lost from the aluminum foils as compared to a filter-based sampler. These losses are due to volatilization and bounce-off from the MOUDI stages. High nitrate losses from the MOUDI are also observed during the summer (above 70%). Good agreement between the gravimetrically determined mass and the sum of the masses of the individual compounds is obtained, if the lost mass from organics and the aerosol water content are included for the summer. For the winter no significant losses of material are detected and there exists reasonable agreement between the gravimetrical mass and the sum of the concentrations of the individual compounds.Ultrafine particles (below 100 nm) account on average, for o 5% of the PM 2.5 mass, and show different composition for the summer and the winter. During the summer the ultrafine mass is 50% carbonaceous material (organic material and elemental carbon) and 50% inorganic (mainly sulfate and ammonium); during the winter these percentages are 70% and 30%, respectively.

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“…It has been shown that bounce decreases with the coating thickness (Pak et al 1992; Reischl and John 1978). A greased coating with a thickness of a few micron can rapidly become ineffective.…”

Section: Resultsmentioning

confidence: 99%

“…Therefore the substrate must have a large enough capacity to maintain high collection ef ciency, even under heavy loading conditions. Other factors such as the grease coating thickness (Pak et al 1992;Reischl and John 1978), particle hardness (Hinds et al 1999), and shape can also affect bouncing behavior.…”

Section: Design Considerations On Inertial Impactorsmentioning

confidence: 99%

Development and Laboratory Performance Evaluation of a Personal Multipollutant Sampler for Simultaneous Measurements of Particulate and Gaseous Pollutants

Demokritou¹,

Kavouras²,

Ferguson³

et al. 2001

Aerosol Science and Technology

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A personal multipollutant sampler has been developed. This sampler can be used for measuring exposures to particulate matter and criteria gases. The system uses a single personal sampling pump that operates at a ow rate of 5.2 l/min. The basic unit consists of two impaction-based samplers for PM 2:5 and PM 10 attached to a single elutriator. Two mini PM 2:5 samplers are also attached to the elutriator for organic carbon (OC), elemental carbon (EC), sulfate, and nitrate measurements. For the collection of nitrate and sulfate, the minisampler includes a miniaturized honeycomb glass denuder that is placed upstream of the lter to remove nitric acid and sulfur dioxide and to minimize artifacts. Two passive samplers can also be attached to the elutriator for measurements of gaseous copollutants such as O 3 , SO 2 , and NO 2 .The performance of the multipollutant sampler was examined through a series of laboratory chamber tests. The results showed a good agreement between the multipollutant sampler and the reference methods. The overall sampler performance demonstrates its suitability for personal exposure assessment studies.

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Effect of Coating Thickness on Particle Bounce in Inertial Impactors

Cited by 79 publications

References 16 publications

Comparison between CARIBIC Aerosol Samples Analysed by Accelerator-Based Methods and Optical Particle Counter Measurements

Comparison between CARIBIC Aerosol Samples Analysed by Accelerator-Based Methods and Optical Particle Counter Measurements

Mass size distributions and size resolved chemical composition of fine particulate matter at the Pittsburgh supersite

Development and Laboratory Performance Evaluation of a Personal Multipollutant Sampler for Simultaneous Measurements of Particulate and Gaseous Pollutants

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