Certain facilities with visible emissions may be required to observe, evaluate, and report plume opacity. Opacity is the degree to which a plume obscures, or blocks out, light. Regulations relating to opacity are found throughout Indiana’s air pollution control rules at Title 326 of the Indiana Administrative Code (326 IAC).
Smoke school is the term for training and certification for performing visible emissions observations and reading opacity according to approved methods, including U.S. EPA Method 9 and Method 22. IDEM maintains a list of firms that provide smoke school (Currently Unavailable) in Indiana.
Compliance assistance is available upon request.