MPCA Guidance Regarding Method 202
The new method 202 effective 1/1/2011 instructs “if the gas filtration temperature never exceeds 30 °C (85 °F), then use of this method is not required to measure total primary PM.” This can be taken to say that units with truly ambient stack temperatures do not need to be measured for condensible particulate matter. Although this rationale may make sense in certain instances for federal particulate standards, Minnesota Rules still define total particulate matter as the sum of the filterable (front-half) particulate plus the organic condensibles and PM10 as the sum of the filterable plus the organic and inorganic condensibles (back-half). The same applies for PM2.5 now as well. Even though the method says that stacks less than 85°F may not need to be measured for condensibles, facilities that have to comply with Minn. Rule particulate limits will need to continue measuring for these and report according to the requirements of Minn. Rules 7017.2060, subps. 3(B) and 4(B) unless by rule or permit condition they are specifically allowed to do otherwise.
The new, post 1/1/2011 Method 202 as now outlined in rule will be considered the standard if 202 is listed in a test plan. Facilities can measure for condensibles a number of different ways and should communicate how they intend to do this in the test plan and as part of the pretest meeting. Minn. R. 7017.2050, subp. 2 gives MPCA authority to approve alternative or equivalent test methods provided they meet the requirements of Minn. Rule and EPA guidance. In some instances, facilities and test companies may wish to use the original wet-impinger method. The MPCA will accept this in appropriate instances however using the original method now needs to called out as an alternative test method in the test plan. Requests for an alternative test method must be made with each subsequent performance test and approval must be granted in order for the results to be accepted.
Minn. R. 7017.2060 subps. 3(C) and 4(D) does state the determination of condensible particulate matter may be waived if it can be demonstrated through previous performance test results or mass balance calculations that the emission unit is not a source of condensible particulate matter emissions. In order to request such a waiver, the unit would typically need to be a truly ambient source, like a crusher, grain handling operation, etc., where the stack gas has not been cooled by a scrubber and no additive is present in the material which has the potential to volatilize and result in condensible emissions. Previous test results would need to be supplied to provide evidence of this and if approved, the test would need to then be completed using a unheated filter.
It will be the facilities responsibility to submit the necessary evidence in order to request a waiver along with the test plan if not prior. Emission units and pollution control equipment will need to be in similar condition and operating at the same rates as those exhibited at the time of the example testing. In order to make these determinations, the MPCA will also typically not allow for shortened test notifications. A decision made for one test does not predicate condensibles will never again be required for future testing. It will be the facilities responsibility to request condensibles are not to be required and provide supporting evidence for each subsequent test.