News

February 20, 2018

Proposed Changes to EPA Method 202 for Condensable Particulate Matter (CPM)

On August 23, 2017, the U.S. Environmental Protection Agency (EPA) proposed technical revisions and editorial changes to clarify and update the procedures specified in Method 202.

Method 202 describes the procedures that stack testers must follow to measure condensable particulate matter (CPM) emissions from stationary sources. It is known as the “dry impinger” method.

This proposal does not modify the method significantly. It is in line with steps EPA has taken since 2010 to improve the implementation of the method and promote consistency in the measurement of CPM.

EPA is proposing the following revisions to Method 202:

o Revisions to the procedures for determining the systematic error of the method, which is used to correct the results of the measurements made using this method;

o Removes some procedural options to the method to standardize the way method is performed while also eliminating the potential for additional blank contamination;

o Revise overly prescriptive requirements for the method specific reagents and equipment with more flexible performance-based criteria; and

o Revise the method to correct inconsistent terminology, improve the readability, and to simplify the text to aid in consistent implementation of the method.

EPA will accept comment on the proposal for 60 days after publication in the Federal Register.

BACKGROUND

In 2010, the EPA revised Method 202 for determining condensable particulate matter (PM) from stationary sources to improve the measurement of fine PM emissions. These revisions increased the precision of Method 202 and reduced potential bias. The revisions improved the consistency in the measurements obtained between source tests performed under different regulatory authorities.

In 2014, the EPA issued interim guidance on the treatment of CPM results in the Prevention of Significant Deterioration (PSD) and Nonattainment NSR Permitting Programs. The guidance addressed concerns that the use of source-specific CPM test results obtained with Method 202 could include a positive bias -- resulting in the overestimation of emissions due to the potential for blank contamination associated with the implementation of Method 202. As part of this guidance, the EPA announced plans to issue guidance on best practices for Method 202 implementation and to revise Method 202 as necessary.

In 2016, EPA issued the Best Practices Handbook to mitigate the bias concern, which was developed with significant input from stakeholders and trade groups. The proposed technical revisions incorporate the findings from the handbook.

FOR MORE INFORMATON

Download the proposed rule at https://www.epa.gov/emc/emc-proposed-test-methods.

For further information about the proposal, contact Ned Shappley at EPA’s Office of Air Quality Planning and Standards at (919) 541-7903 or [email protected].

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