NOTE :Do not allow the sampler assembly to be inverted at any time. Turning the cyclone to
anything more than a horizontal orientation may deposit oversized material from the cyclone
body onto the filter.
SAMPLE PREPARATION:
8. Remove the top and bottom plugs from the filter cassette. Equilibrate for at least 2 h in an
environmentally controlled area or chamber.
CALIBRATION AND QUALITY CONTROL:
9. Zero the microbalance before all weighings. Use the same microbalance for weighing filters
before and after sample collection. Calibrate the balance with National Institute of Standards and
Technology Class S-1.1 or ASTM Class 1 weights.
10. The set of replicate field samples should be exposed to the same dust environment, either in a
laboratory dust chamber [8] or in the field [9]. The quality control samples must be taken with the
same equipment, procedures, and personnel used in the routine field samples. Calculate precision
from these replicates and record relative standard deviation ( ) on control charts. Take corrective
action when the precision is out of control [8].
MEASUREMENT:
11. Weigh each filter, including field blanks. Record this post-sampling weight, (mg), beside its
corresponding tare weight. Record anything remarkable about a filter (e.g., visible particles,
overloading, leakage, wet, torn, etc.).
CALCULATIONS:
12. Calculate the concentration of respirable particulate, (mg/m³), in the air volume sampled, (L):