• Roger J. CHENG, ASRC SUNY UALBANY

• ATMOSPHERIC SCIENCES RESEARCH CENTER
• STATE UNIVERSITY of NEW YORK

• HOLLOW PARTICLES in the ATMOSPHERE
• ROGER J CHENG, ASRC SUNY UALBANY

IF HOLLOW PARTICLES ARE COMMON in the ATMOSPHERE

• THEN INSTRUMENTS that MEASURE PARTICLE SIZE
• CANNOT BE USED TO OBTAIN PARTICLE MASS (TSP)

• *****POWER PLANT EMISSION****

• ROGER J. CHENG, ASRC UALBANY SUNY

Roger J. Cheng, Duncan C. Blanchard and Ramon J. Ciprianoa

• Atmospheric Sciences Research Center
• State University of New York at Albany
• Received 12 December 1986; accepted 31 July 1987.

Abstract

Some non-volatile materials dissolved in water drops will, upon evaporation of the water, produce a hollow shell of the material. Though known for years in the chemical engineering literature, this fact was not appreciated by those working with the marine sea-salt aerosol. Our laboratory experiments show that a majority of seawater drops in free fall in air with a relative humidity less than about 60% evaporate, become salt-saturated, and change phase to produce hollow sea-salt particles. Some hollow salt particles have been found in marine air, though further investigation is required to show the extent of this phenomenon. Expressions have been derived from which both the size of the original drop of seawater and its salt supersaturation at the time of phase change can be calculated from the inner and outer radii of the salt shell. If hollow particles are common in the marine aerosol, then instruments that measure particle size cannot be used to obtain particle mass.

Résumé

Certaines substances non volatiles dissoutes dans les gouttes d'eau produisent, à l'évaporation de l'eau, des coquilles creuses. Ce processus est bien connu en génie chimique, et pourtant il n'en est pas tenu compte dans les travaux sur les aérosols salins océaniques. Nos expériences de laboratoire montrent que lorsque des gouttes du de mer tombent en chute libre dans de l'air à moins de 60% d'humidité relative, la plupart d'entre elles arrivent à saturation et changent de phase pour produire des particules salines creuses. On a d'ailleurs trouvé des particules creuses de sel dans de l'air marin, mais d'autres recherches sont nécessaires pour connaître l'étendue du phénomène. On présente des relations qui donnent la dimension de la goutte originale d'eau de mer, ainsi que la sursaturation au changement de phase, à partir des rayons intérieurs et extérieurs de la coquille de sel. S'il est prouvé que les particules creuses sont courantes dans l'aérosol marin, on ne pourra pas utiliser les appareils qui mesurent les dimensions des particules pour évaluer la masse de l'aérosol.

 

Atmospheric Research Volume 22, Issue 1, Pages 15-25 June 1988,

ROGER J. CHENG, ASRC SUNY UALBANY

CATALYST PLUGGING in VEHICLES

• INDUSTRIALLY GENERATED ASBESTOS FIBERS:
• CHARACTERIZATION and ENVIRONMENTAL HEALTH

• ROGER J CHENG, ASRC UALBANY SUNY

References:

1, Cheng, R.J.and A.M. Pitaniello "Characterization and Identification of Asbestos". Proceedings of AGGIH Symposium on Asbestos Identification and Measurement. OSRA Training Center, Des Plaines, Ill. USA, 1979

2, Cheng,R.J. "The Identification of Asbestos by Electron Microscopy", Proceedings of the Air Pollution Control Association, 73rd Annual Meeting, Montreal, Canada, 1980

3, Hershey, D.C and R.J. Cheng "Identifying Asbestos in Building Material" Proceedings of Pittsburgh Conference & Exposition on Analytical Chemistry and Applied Spectroscopy, New Orleans, LA.USA, 1988

4, Cheng, R.J. "Industrially Generated Asbestos Fibers: Characterization and Environmental Risk Assessment". Workshop on Indoor air Pollution and Environmental Health, Sponsored by The Environmental Protection Administration, Taipei, Taiwan, China, 1989

5, Reports on Asbestos by: A, American Lung Association B, Consumer Product Safety Commission C, United States Environmental Protection Agency

• HOLE in ONE on ASRC'S 18th GREEN
• CHENG with HIS TOYS and HAVING FUN-ASRC-SUNY