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Aerosol Particle Counters FRANK T GUCKER Professor of Chemistry Indiana University Bloomington, Indiana Two general methods have been used for determining particulate concentration in aerosols. The first involves the collection of the particulate matter, usually by precipitation on suitable slides, and the counting of the particles; the second involves direct counting in the aerosol phase. A special method of counting aerosol particles is applicable only to viable microorganisms. In this case a known volume of the aerosol is passed through a suitable cotton plug filter or better through a capillary impinger jet operating under water as described by T. Rosebury.30 If the organisms washed from the filter or collected in the impinger are deposited on agar and incubated, a colony count will give the number of particles. Beside its limited applicability, the process is slow and involves the uncertain viability of the organisms. More generally, the particles may be precipitated by settling or by means of a thermal or electrostatic precipitator. The slide may then be examined visually or photographically with the help of an optical or electron microscope. Ingenious automatic electronic methods of scanning and counting have been recently introduced to determine the number, size, and sometimes even the shape of the particles. Most of these methods have been developed in England and were described at the Conference on the Physics of Particle Size Analysis held at the University of Nottingham in 1954.16 A discussion of these methods is beyond the scope of the present article which is confined to counting in the aerosol phase. The ultramicroscope was used for studying particles in the aerosol phase by P. V. Wells and R. H. Gerke in 1919 and later by R. Whyt- law-Gray and his collaborators at the beginning of their long series of studies of aerosols. In 1927 the latter group developed a special dark- field cell for visual counting of aerosol particles without the difficulties encountered in the Zsigmondy slit ultramicroscope. In 1927 also H. L. Green adapted the Wilson-Shimizu cloud chamber to condense moisture upon small aerosol particles and thus increase their size so that they can be photographed. In 1949 A. L. Chaney developed a dust camera 284
Object Description
Purdue Identification Number | ETRIWC195625 |
Title | Aerosol particle counters |
Author | Gucker, Frank T. |
Date of Original | 1956 |
Conference Title | Proceedings of the eleventh Industrial Waste Conference |
Conference Front Matter (copy and paste) | http://earchives.lib.purdue.edu/cdm4/document.php?CISOROOT=/engext&CISOPTR=4951&REC=18 |
Extent of Original | p. 284-312 |
Collection Title | Engineering Technical Reports Collection, Purdue University |
Repository | Purdue University Libraries |
Rights Statement | Digital object copyright Purdue University. All rights reserved. |
Language | eng |
Type (DCMI) | text |
Format | JP2 |
Date Digitized | 2008-09-22 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Resolution | 300 ppi |
Color Depth | 8 bit |
Description
Title | page 284 |
Collection Title | Engineering Technical Reports Collection, Purdue University |
Repository | Purdue University Libraries |
Rights Statement | Digital object copyright Purdue University. All rights reserved. |
Language | eng |
Type (DCMI) | text |
Format | JP2 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Transcript | Aerosol Particle Counters FRANK T GUCKER Professor of Chemistry Indiana University Bloomington, Indiana Two general methods have been used for determining particulate concentration in aerosols. The first involves the collection of the particulate matter, usually by precipitation on suitable slides, and the counting of the particles; the second involves direct counting in the aerosol phase. A special method of counting aerosol particles is applicable only to viable microorganisms. In this case a known volume of the aerosol is passed through a suitable cotton plug filter or better through a capillary impinger jet operating under water as described by T. Rosebury.30 If the organisms washed from the filter or collected in the impinger are deposited on agar and incubated, a colony count will give the number of particles. Beside its limited applicability, the process is slow and involves the uncertain viability of the organisms. More generally, the particles may be precipitated by settling or by means of a thermal or electrostatic precipitator. The slide may then be examined visually or photographically with the help of an optical or electron microscope. Ingenious automatic electronic methods of scanning and counting have been recently introduced to determine the number, size, and sometimes even the shape of the particles. Most of these methods have been developed in England and were described at the Conference on the Physics of Particle Size Analysis held at the University of Nottingham in 1954.16 A discussion of these methods is beyond the scope of the present article which is confined to counting in the aerosol phase. The ultramicroscope was used for studying particles in the aerosol phase by P. V. Wells and R. H. Gerke in 1919 and later by R. Whyt- law-Gray and his collaborators at the beginning of their long series of studies of aerosols. In 1927 the latter group developed a special dark- field cell for visual counting of aerosol particles without the difficulties encountered in the Zsigmondy slit ultramicroscope. In 1927 also H. L. Green adapted the Wilson-Shimizu cloud chamber to condense moisture upon small aerosol particles and thus increase their size so that they can be photographed. In 1949 A. L. Chaney developed a dust camera 284 |
Resolution | 300 ppi |
Color Depth | 8 bit |
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