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(a) The test procedures prescribed in this subpart shall be used to test the performance of candidate methods for PM 10 against the performance specifications given in table D-1. Except as provided in paragraph (b) of this section, a test sampler or samplers representative of the sampler described in the candidate method must exhibit performance better than, or equal to, the specified value for each performance parameter, to satisfy the requirements of this subpart.
(b) For a candidate method using a PM 10 sampler previously approved as part of a designated PM 10 method, only the test for precision need be conducted and passed to satisfy the requirements of this subpart. For a candidate method using a PM 10 sampler inlet previously approved as part of a designated PM 10 method, the tests for precision and flow rate stability must be conducted and passed to satisfy the requirements of this subpart; the tests for sampling effectiveness and 50 percent cutpoint need not be conducted if suitable rationale is provided to demonstrate that test results submitted for the previously approved method are applicable to the candidate method.
(c) The liquid particle sampling effectiveness and 50 percent cutpoint of a test sampler shall be determined in a wind tunnel using 10 particle sizes and three wind speeds as specified in table D-2. A minimum of 3 replicate measurements of sampling effectiveness shall be required for each of the 30 test conditions for a minimum of 90 test measurements.
(d) For the liquid particle sampling effectiveness parameter, a smooth curve plot shall be constructed of sampling effectiveness (percent) versus aerodynamic particle diameter (µm) for each of the three wind speeds. These plots shall be used to calculate the expected mass concentration for the test sampler, using the procedure in §53.43(a). The candidate method passes the liquid particle sampling effectiveness test if the expected mass concentration calculated for the test sampler at each wind speed differs by no more than ±10 percent from that predicted for the “ideal” sampler.*
* The sampling effectiveness curve for this “ideal” sampler is described by column 5 of table D-3 and is based on a model that approximates the penetration of particles into the human respiratory tract. Additional information on this model may be found in a document entitled, “Particle Collection Criteria for 10 Micrometer Samplers,” which is available from the Quality Assurance Division (MD-77), Environmental Monitoring Systems Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711.
(e) For the 50 percent cutpoint parameter, the test result for each wind speed shall be reported as the particle size at which the curve specified in §53.40(d) crosses the 50 percent effectiveness line. The candidate method passes the 50 percent cutpoint test if the test result at each wind speed falls within 10±0.5 µm.
(f) The solid particle sampling effectiveness of a test sampler shall be determined in a wind tunnel using 25 µm particles at 2 wind speeds as specified in table D-2. A minimum of three replicate measurements of sampling effectiveness for the 25 µm solid particles shall be required at both wind speeds for a minimum of 6 test measurements.
(g) For the solid particle sampling effectiveness parameter, the test result for each wind speed shall be reported as the difference between the average of the replicate sampling effectiveness measurements obtained for the 25 µm solid particles and the average of the replicate measurements obtained for the 25 µm liquid particles. The candidate method passes the solid particle sampling effectiveness test if the test result for each wind speed is less than, or equal to, 5 percent.
(h) The precision and flow rate stability of three identical test samplers shall be determined at a suitable test site by simultaneously sampling the PM 10 concentration of the atmosphere for 10 periods of 24 hours.
(i) For the precision parameter, the test result for each of the 10 periods of 24 hours shall be calculated using the procedure in §53.43(c). The candidate method passes the precision test if all of the test results meet the specifications in table D-1.
(j) For the flow rate stability parameter, the test results for each of the three test samplers and for each of the 10 periods of 24 hours shall be calculated using the procedure in §53.43(d). The candidate method passes the flow rate stability test if all of the test results meet the specifications in table D-1.
(k) All test data and other documentation obtained from or pertinent to these tests shall be identified, dated, signed by the analyst performing the test, and submitted to EPA.
| Performance parameter | Units | Specification |
|---|---|---|
| 1. Sampling effectiveness: | ||
| A. Liquid particles | Percent | Such that the expected mass concentration is within ±10 percent of that predicted for the ideal sampler. |
| B. Solid particles | Percent | Sampling effectiveness is no more than 5 percent above that obtained for liquid particles of same size. |
| 2. 50 Percent cutpoint | µm | 10±µ.5 µm aerodynamic diameter. |
| 3. Precision | µg/m 3 or percent | 5 µg/m 3 or 7 percent for three collocated samplers. |
| 4. Flow rate stability | Percent | Average flow rate over 24 hours within ±5 percent of initial flow rate; all measured flow rates over 24 hours within ±10 percent of initial flow rate. |