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Emission Monitoring Unit (Testing Group)

The responsibility of the Emission Monitoring Unit is to provide source testing guidance for the regulated community in Ohio. The Active National Directory of Source Emissions Testing provides a listing of stack testing firms in Ohio.

Intent to Test Notification

Intent to Test Notification

The most recent version of the Intent to Test notification form is also available:

Emission Test Methods

Ohio EPA offers links to the U.S. EPA Emissions Measuring Technical Information Center to ensure delivery of the most up-to-date information possible regarding testing methods.

Guidance Documents

Testing Guidance Documents

These guidance documents are downloadable files in Word Perfect format. You must first unzip the files to view them.




Effective Duct Area Calculation for Ducts with Sediment Build-up


Acronyms Used in Emission Measurement Discussions and Regulations


Guidelines for Determining Capture Efficiency


Revised Capture Efficiency Guidance for Control of Volatile Organic Compound Emissions


Particulate Sampling in Cyclonic Flow


Derivation of Delta H

DQO.ZIP (139 K)

Guidance for the Data Quality Objectives Process


Evacuated Cylinder Procedure


Explanation of Ohio EPA's "Test at Max" Policy for Requiring Performance Testing to be Conducted While Emission Units Operate at Maximum Capacity

25VS25A [PDF]

Guidance Regarding the Use of Methods 25 and 25a for Measuring Gas Stream Volatile Organic Compounds (VOCs) Concentration

26VS26A. [PDF]

Background Paper for Method 26 and 26a


Determination of Stack Gas Velocity and Volumetric Flow Rate (Three-dimensional Pitot Tube)


Isokinetic Equation for Method 5d

Test Summaries

Audit Program

Testing Audit Program

Ohio EPA participates in U.S. EPA's stationary source testing audit program. Visit the U.S. EPA Emissions Measurement Center's Technical Support website to access information regarding which test methods have audits available and how to order audit samples. Audits provide a means for improved quality assurance of laboratory analyses and other aspects of source testing that may otherwise go unwitnessed and under-scrutinized.

Audits are required to be employed whenever samples are available.