LABORATORY PERFORMANCE COMPARISON OF RESPIRABLE SAMPLERS
Resource
AMERICAN INDUSTRIAL HYGIENE ASSOCIATION JOURNAL v.60 n.5 pp.601-611
Journal
AMERICAN INDUSTRIAL HYGIENE ASSOCIATION JOURNAL
Journal Volume
v.60
Journal Issue
n.5
Pages
601-611
Date Issued
1999
Date
1999
Author(s)
CHEN, CHIH-CHIEH
Abstract
Three respirable samplers (nylon cyclone, SKC cyclone, and
foam sampler) were tested for aerosol penetration as a
function of aerosol size, to examine the precision and the
accuracy with respect to the newly defined respirable
convention. An ultrasonic atomizing nozzle was used to
generate micrometer-sized liquid dioctylphthalate or solid
potassium sodium tartrate aerosol particles, with count
median diameters of 3 mu m or 8 mu m, and geometric standard
deviation of 1.6, depending on the properties of the
solution to be nebulized. The aerosol number concentration
and size distribution upstream and downstream of the
samplers were measured by using an aerodynamic particle
sizer, which was calibrated against a settling velocity
chamber. The results showed that a newly developed foam
sampler meets the requirements of the 50% cutoff size as
well as the slope of the international respirable convention
. For considering both the accuracy and precision of the
samplers, it may be inappropriate to select the estimator
with least variance or to pick the estimator with least bias
. Instead, the concept of the mean square error (MSE) should
be applied, because it leads to the best combination of
small bias and small variance. Analysis of MSE showed that
the foam sampler performed better than the cyclone samplers,
if the challenge aerosol was liquid. For solid particles
larger than 6 mu m, the foam samplers apparently experienced
significant particle bounce off and became less precise and
less accurate as compared with the cyclones.
Subjects
cyclone samplers
foam samplers
international respirable convention
Type
journal article