D=Aerodynamic diameter of the test particle, cm (g/cm3).

Q-Gas flow rate through the calibration stage at inlet conditions, cm3/sec. μ=Gas viscosity, micropoise.

A Total cross-sectional area of the jets of the calibration stage, cm2.

d=Diameter of one jet of the calibration stage, cm.

5.4.4.4 Determine Stkso for each calibration stage by plotting Ev versus Stk on loglog paper. Stkso is the Stk number at 50 percent efficiency. Note that particle bounce can cause efficiency to decrease at high values of Stk. Thus, 50 percent efficiency can occur at multiple values of Stk. The calibration data should clearly indicate the value of Stkso for minimum particle bounce. Impactor efficiency versus Stk with minimal particle bounce is characterized by a monotonically increasing function with constant or increasing slope with increasing Stk.

5.4.4.5 The Stkso of the first calibration stage can potentially decrease with decreasing nozzle size. Therefore, calibrations should be performed with enough nozzle sizes to provide a measured value within 25 percent of any nozzle size used in PM10 measurements.

5.4.5 Criteria For Acceptance. Plot Ev for the first calibration stage versus the square root of the ratio of Stk to Stkso on Figure 9 of this method. Draw a smooth curve through all of the points. The curve shall be within the banded region.

D50=Diameter of particles having a 50 percent probability of penetration, μm.

f. Stack gas fraction O1, by volume, dry basis.

K1=0.3858 'K/mm Hg (17.64 °R/in. Hg). M-Wet molecular weight of stack gas, g/ g-mole (lb/lb-mole).

M. Dry molecular weight of stack gas, g/ g-mole (1b/1b-mole).

Pbar Barometric pressure at sampling site, mm Hg (in. Hg).

P.-Absolute stack pressure, mm Hg (in. Hg).

Q. Total cyclone flow rate at wet cyclone conditions, m3/min (ft3/min).

Qata) Total cyclone flow rate at standard conditions, dscm/min (dscf/min).

=

Tm Average absolute temperature of dry meter, 'K (R).

T. Average absolute stack gas temperature, 'K (R). Vw(std)=Volume of water vapor in gas sample (standard conditions), scm (scf). =Total sampling time, min.

=

Viscosity of stack gas, micropoise.

6.2 Analysis of Cascade Impactor Data. Use the manufacturer's recommended procedures to analyze data from cascade impactors.

6.3 Analysis of Cyclone Data. Use the following procedures to analyze data from a single stage cyclone.

6.3.1 PM10 Weight. Determine the PM catch in the PM10 range from the sum of the weights obtained from Container Numbers 1 and 3 less the acetone blank.

6.3.2 Total PM Weight (optional). Determine the PM catch for greater than PM10 from the weight obtained from Container Number 2 less the acetone blank, and add it to the PM10 weight.

6.3.3 PM10 Fraction. Determine the PM10 fraction of the total particulate weight by dividing the PM10 particulate weight by the total particulate weight.

6.3.4 Aerodynamic Cut Size. Calculate the stack gas viscosity as follows:

H=C1+C2T,+C1T,2+C1fo2-CsBws

6.3.4.1 The PM10 flow rate, at actual cyclone conditions, is calculated as follows:

where B1=0.027754 for metric units (0.15625 for English units).

6.3.5 Acceptable Results. The results are acceptable if two conditions are met. The first is that 9.0 μm < Dso < 11.0 μm. The second is that no sampling points are outside Apmin and Apmax, or that 80 percent < I < 120 percent and no more than one sampling point is outside Apmin and APmax. If Dso is less than 9.0 μm, reject the results and repeat the test.

7. Bibliography

1. Same as Bibliography in Method 5.

2. McCain, J.D., J.W. Ragland, and A.D. Williamson. Recommended Methodology

for the Determination of Particle Size Distributions in Ducted Sources, Final Report. Prepared for the California Air Resources Board by Southern Research Institute. May 1986.

3. Farthing, W.E., S.S. Dawes, A.D. WIlliamson, J.D. McCain, R.S. Martin, and J.W. Ragland. Development of Sampling Methods for Source PM10 Emissions. Southern Research Institute for the Environmental Protection Agency. April 1989. NTIS PB 89 190375, EPA/600/3-88-056.

4. Application Guide for Source PM10 Measurement with Constant Sampling Rate, EPA/600/3-88-057.