On June 10, 2019, the EPA released a revision to EPA Method 308, Determination of Methanol Emission from Stationary Sources. The revision includes amendments to both the sampling and analytical requirements that impact sample collection in the field and associated in-lab analytical procedures. Click here for a link to the update.
Below are highlights of the amended method.
Updates to Sampling Protocol
- Co-located Spike Run
- New Requirement: Addition of a co-located spike run for each sampling point; the spiked run is to be collected from a separate sampling train (similar to EPA Method 18)
- New Requirement: Spikes must be recovered between 70-130% even though methanol catch weights are not adjusted by the recovery efficiency
- Leak Check
- Previous requirement: Only a post-test leak check was mandatory
New requirement: Both a pre and post-test leak check now are mandatory - Administrative updates to Section 8.1.2 to clarify the contradictions in the leak acceptance criteria
- Previous requirement: Only a post-test leak check was mandatory
Updates to Analytical Protocol
- Desorption Solvent
- Previous requirement: Silica gel sorbent tubes were previously desorbed by the lab using a solvent of 3% n-propanol
New requirement: The silica gel sorbent tubes now are desorbed with deionized water - New requirement: Allowing Mercury-free thermometers in calibrating temperature sensors
- Previous requirement: Silica gel sorbent tubes were previously desorbed by the lab using a solvent of 3% n-propanol
What do these changes mean for you?
- As the addition of a required, co-located spike train doubles the equipment and analytical cost required for a single test, please plan ahead to ensure additional equipment is available.
- Because the spike must now contain 40-60% of the expected methanol catch of the unspiked sampling train, it is critical to pay attention to what is in the stack to allow for proper spike preparation.
- Due to the revised leak checking protocol, please allocate more time on your test schedule.
- With water being used for the desorption solvent, compounds that would normally have been masked by the n-propanol peak can now be chromatographed to provide more detailed information, if desired.
Contact us today to learn more about the EPA Method 308 revisions or for assistance in determining your appropriate spiking amounts!
