Measurement of Nanometer Aerosols

Sinclair, David

doi:10.1080/02786828608959087

Cited by 16 publications

(2 citation statements)

References 25 publications

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“…Several novel diffusion batteries have been developed by Sinclair (see the review paper by Sinclair [105], who used metal disks containing uniform parallel holes of a finite lengththe so-called collimated hole structureand layers of fine stainless steel screens as diffusion collectors). A commercial version of the device is shown in Figure 24.…”

Section: Electrical Aerosol Analyzers the High Electric Mobility Of S...mentioning

confidence: 99%

Advances in instrumentation for atmospheric aerosol measurement

Pui

Liu

1988

Phys. Scr.

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Instruments for airborne particle sampling and measurement are important tools for the study of particulate air contaminants. As such they are important in air quality, air pollution and industrial hygiene studies. Particle measuring instruments are important also for various industrial processes, such as clean room monitoring and contaminant measurement in clean process gases used in semiconductor manufacturing. This paper reviews the advances in particle measuring and sampling instruments, with particular emphasis on instruments for atmospheric studies. Devices for particle generation needed for instrument calibration and experimental purposes are also covered in this review. instruments Manual sampling devicesManual sampling devices are needed to collect atmospheric particles for subsequent gravimetric and/or chemical analysis. The collection is usually done with a filter sampler to give an integrated sample and a time averaged concentration measurement. A relatively low sampling flow rate of a few

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Section: Electrical Aerosol Analyzers the High Electric Mobility Of S...mentioning

confidence: 99%

Advances in instrumentation for atmospheric aerosol measurement

Pui

Liu

1988

Phys. Scr.

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“…These evolved to honeycomb structures and finally to wire screens. 20 This development is analogous to the development of diffusion denuders for sampling semi-volatile species, which started with tubing bundles, 9 progressed to annular geometry, 11 and then to honeycomb structures. 19 Our approach uses a fabric as the denuder substrate, analogous to wire screen denuders that collect very fine particles in diffusion batteries.…”

Section: Introductionmentioning

confidence: 99%

A Fabric Denuder for Sampling Semi-Volatile Species

Fitz

Motallebi

2000

Journal of the Air & Waste Management Association

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A new style of diffusion denuder has been evaluated specifically for sampling HNO 3 . A coated fabric is used as the denuder substrate, which can be loaded directly into a standard filter holder. This approach allows direct denuder sampling with no additional capital costs over filter sampling and simplifies the coating and extraction process.Potential denuder materials and coatings were evaluated in the laboratory to test the removal efficiency. NaCl coatings were used to assess more than 20 materials for HNO 3 collection efficiency. Particle retention, which would cause a denuder to have a positive bias for gas concentration measurements, was evaluated by ambient air sampling using particulate sulfate as the reference aerosol. Particle retention varied from 0 to 15%, depending on the denuder material tested. The best performing material showed an average particle retention of less than 3%.Denuder efficiency of four fabric materials was tested under ambient conditions to determine removal efficiency. The fabric denuder method was compared with a long path-length Fourier transform infrared (FTIR) spectrometer, a tunable diode laser absorption spectrometer (TDLAS), and a denuder difference sampler to independently measure HNO 3 . HNO 3 collection efficiency was typically 90% for the denuders, whether coated with NaCl or not. For 10-L/min sampling rates with the fabric denuder, the square of the correlation coefficient with IMPLICATIONS A simple fabric material used as a diffusion denuder has been shown to be an effective and inexpensive method to measure species such as HNO 3 and NH 3 which partition into both gaseous and particulate phases. The low cost of this approach compared with other types of denuders may encourage more measurements of these air pollutants. With a larger database available, the environmental and health effects of these species may be better assessed.the FTIR spectrometer was 0.73, compared to 0.24 with the TDLAS. INTRODUCTIONBackground HNO 3 in the atmosphere may pose a significant health risk and environmental hazard. In the atmosphere, HNO 3 and NH 3 are in equilibrium with NH 4 NO 3 particulate matter. These particles are primarily in the PM 2.5 size range, a particulate range for which a new federal ambient air quality standard has been promulgated.

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Direct Reading Instruments for the Determination of Aerosols and Particulates

Pui

Chen

2000

Encyclopedia of Analytical Chemistry

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Solid and liquid particles suspended in a gas are referred to as aerosols. The suspending medium can be air, or some other gases, such as argon, nitrogen, helium, etc. Aerosols have found numerous scientific and technical applications. Beneficial applications include pharmaceutical aerosols for medical inhalation therapy or diagnosis, industrial aerosols for coating wave guides, refractories, gas sensors and semiconductors, as well as particles ofmodern materials for forming advanced ceramics, optical and optoelectronic devices, cosmetic products, paint pigments, and catalysts. Harmful effects of aerosols include atmospheric aerosols that contribute to urban air pollution and global radiation balance, dust particles ingested by engines causing premature failure of the equipment, and particles deposited on semiconductor wafers causing device failure and product yield loss. Aerosols and particles can be analyzed by collecting them on a filter or a sampling surface for subsequent microscopic, gravimetric, or chemical analyses. The collection by the samplers gives an integrated sample and a time averaged concentration over a period of hours or days. Direct reading instruments carry out the sampling and analysis within the instrument and the property of interest can be obtained in near real‐time. Direct reading instruments are available to cover particles in the size range of 0.002 to 100 µm. These instruments have fast time response and can follow rapid changes in both particle size and concentration. Good counting statistics can also be obtained because repeated measurements can be performed in a short time. However, these instruments usually rely on indirect sensing techniques and more calibration efforts are usually required.

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Measurement of Nanometer Aerosols

Cited by 16 publications

References 25 publications

Advances in instrumentation for atmospheric aerosol measurement

Advances in instrumentation for atmospheric aerosol measurement

A Fabric Denuder for Sampling Semi-Volatile Species

Direct Reading Instruments for the Determination of Aerosols and Particulates

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