Real-Time Measurement of Correlated Size and Composition Profiles of Individual Atmospheric Aerosol Particles
Received: September 8, 1995 Revised
May 6, 1996 Accepted May 7, 1996 Abstract: In this paper, the unique real-time measurement
capabilities of aerosol time-of-flight mass spectrometry
(ATOFMS) for characterizing atmospheric aerosol
particles are demonstrated. ATOFMS is used to obtain
the aerodynamic size and chemical composition of
individual aerosol particles sampled directly into the
instrument from outdoors. Such measurements are
made in-situ by combining a unique dual-laser
aerodynamic particle sizing system to size and track
individual particles through the instrument and laser
desorption/ionization time-of-flight mass spectrometry
to obtain correlated single particle composition data.
At typical ambient concentrations, the size and
chemical composition of 50-100 particles per minute
can be measured (up to 600 per minute at high
particle concentrations). Presented here for the
first
time are compositionally resolved particle size
distributions of ambient aerosol particles, showing
definitive size/composition correlations. A goal of
these
studies is to ultimately couple data obtained from
the dynamic monitoring of individual particles in
atmospheric systems with that obtained using
conventional ambient aerosol sampling to assist in
sorting out complex field data on atmospheric
processes.
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