Absolute number concentration measurement of submicronmeter particles

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1982

OSTI ID:6003829

Chen, T H.B.

Condensation nuclei in the atmosphere are known to be an important factor in the development of clouds, the occurrence of rainfall, and the formation of particulate air pollutants that can cause undesirable effects on man and his environment. A conventional nuclei counter employs the so-called condensation technique which enables the minute nuclei to grow, in a supersaturated environment, to ..mu..m-sized droplets; the number concentration of the visible droplets is then measured. Since each nucleus grows to a droplet, the number concentration of droplets and nuclei remains the same. The number of droplets is measured by 1) direct observation with a microscope (direct counter), 2) counting from photographs of the droplets (photographic counter), 3) suitably calibrated light transmission (or scattering) measurement (relative photoelectric counter). Most of the widely-used counters are relative counters. Based on the modified theory, a new condensation nuclei counter was designed to have the following advantages over the widely-used counters: 1) it provides an absolute concentration measurement; and 2) even a small random fluctuation of nuclei concentration can immediately be detected.

• OSTI ID: 6003829
• Country of Publication: United States
• Language: English

Related Subjects

500200* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
AEROSOLS
AIR POLLUTION
AIR SAMPLERS
COLLOIDS
CONDENSATION NUCLEI
DESIGN
DISPERSIONS
EQUIPMENT
FABRICATION
MEASURING METHODS
PARTICLES
PARTICULATES
PERFORMANCE TESTING
POLLUTION
SAMPLERS
SOLS
TESTING