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AEROCET-380 Operation Manual Rev A
continue with erasing the data and then returning to the memory screen. Selecting CANCEL
on the confirmation screen will return to the Memory screen without erasing the data.
Figure 5-4 - Memory Screens
5.3.2 K-Factor
The K-Factor for the mass concentration can be set in the K-Factor screen. A K-Factor is a
multiplier that is related to the specific gravity of the particulate being measured. It improves
the accuracy of the mass measurement when derived from a reference or gravimetric
device, because not all air is created equal. The accuracy of the mass output can be
affected by variations in size, color, shape, and index of refraction of the sampled particles.
The individual user k-factor can be set from 0.1 to 20.0.
The AEROCET-380 calibration is performed using ideal polystyrene latex (PSL) spheres,
which provide a powerful tool for assessing the sensitivity, accuracy, and resolution. The
particle detector is compared to a reference poly-dispersed suspension of PSL spheres in
clean filtered air for both calibration and certification of performance specifications.
Calculate the K-Factor as the reference concentration divided by the AEROCET-380 light
scatter concentration over the same time period. For example, if the reference total
concentration was 51 μg/m
3
and the AEROCET total concentration was 38 μg/m
3
, then the
K-Factor would be 51 divided by 38 or 1.34.
The K-Factor is only valid at the same site and for the same particulate type. If the local
particulate source changes, the K-Factor may no longer be valid.
