What Are Visible Emissions Observations?

EPA Method 9 visible emission observations are taken of visible emissions from emission sources to quantify opacity of the emissions. Method 9 readings must be taken on a periodic basis by qualified observers - individuals that have been trained and qualified in accordance with Method 9. Method 9 qualification testing occurs at a hands-on, in-person event called a smoke school. Smoke schools must use equipment and procedures that meet Method 9 requirements to document the statistical accuracy and reliability of the observer.

Visible emissions observations have two subsets: Opacity methods (i.e., Method 9) and non-opacity methods (i.e., Method 22 or a permit condition requiring an observation without specifying a method). If your organization's permit requires an opacity observation or opacity reading, Method 9 is implied.

Visible emissions observations include:

• Method 9 - which quantifies the opacity level.
• Method 22 - documents the duration of emissions during a specified observation time.
• Quick Check - a momentary glance without specific criteria or requirement.

• The terms, underlying concepts, and principles related to visible emissions observations.
• A brief history of the evolution of VEO that illustrates the importance of compliance.
• What steps need to be taken before performing an opacity reading.
• How to read the opacity of emissions and perform specialized readings. Opacity readers need to understand and avoid interferences that may bias or invalidate observations.
• How to complete the VEO form.