Determination of PM10 Emissions (Constant Sampling Rate Procedure)
This method is for the determination of in-stack particulate emissions to equal or less than an aerodynamic diameter of nominally 10um (PM10) from stationary sources. Note that EPA recognizes that condensible emissions not collected by this in-stack method are also PM10. Emissions that contribute to ambient PM10 are the sum of condensible emissions plus emissions measured by in-stack (Method 201 or 201A). The method states that condensible emissions by be measured by the impinger analysis in combination with this method.
Samples are collected at a constant flow rate from a source using an in-stack cyclone or cascade impactor to separate PM greater than PM10 and on a pre-tared (to a constant weight) glass fiber filter containing no organic binders to collect PM10. A modified Method 17 train consisting of a heated probe, heated filter, cyclone and series of impingers is used. The first two impingers are filled with 100mL of water, the third impinger is left empty, and the fourth impinger is filled with 200-300g of silica gel.
The filters used for sample collection must be dessicated for at least 24 hours at a contant temperature (20 +/- 5.6°C) and pressure to a constant weight (less than or equal to a 0.5mg weight change to the nearest 0.1mg) and pre-tared prior to use. The filter must have a 99.95% efficiency on 0.3 micron dioctyl phthalate smoke particles. The filter and cyclone must be in-stack or maintained at the stack temperature during sampling.
Once the sample has been collected, the filter is removed and placed in a petri dish. If it is necessary to fold the filter, make sure the PM is on the inside of the fold. This is container 1. Container 2 consists of the PM brushed from the interior of the nozzle and cyclone and interior of the exit tube and corresponding acetone rinse. Container 3 called the PM10 fraction consists of the PM brushed from the cyclone exit to the front half of the in-stack filter holder and corresponding acetone rinse. The silica gel from the last impinger is weighed for moisture determination. The impinger water is measured or weighed for moisture determination and is not typically analyzed.
At the laboratory, the filter is dessicated to a constant weight. The amount of PM on the filter is equal to the weight change from the pre-sampling weight and the final constant weight of the filter post-sampling. The volume of Containers 2 and 3 is measured, evaporated to dryness at ambient temperature and pressue, and dessicated for 24 hours to a constant weight.
The sum of Containers 1 and 3 (minus contribution from the acetone blank) is equal to the amount of PM10 in the sample. The Total PM as defined by the method is equal to results of Container 2 (minus contribution from the acetone blank) plus the PM10 weight. Per the method, the non-isokinetic sampling error for the cyclone PM is theoretically larger than the error for the PM10 catch. Therefore, adding all fractions to get a Total PM is not as accurate as Method 5 or 201.
(EPA 40CFR Part 61 Appendix M)