Opacity Test Rules During Take Images of Stack Emission Smoke or PM Dust

Follow the Rules

 • The same rules apply to ALT 082 as they do to Method 9

 • 3 Stack height rule

 • Sun is within 140° behind the camera/observer 

• No observations can be performed when the sun is directly overhead

 • No plume multipliers (folding over, lipsticking, mushrooming)

 • No interfering plumes (Combining sources)

 • Identify the Regions of Interest (ROI) within the frame

 • Contrasting background with a consistent Horizontal Line of Light

 • Even light intensity

 • No shadows

 • All shadows

 • Even “like” colors

 • Background Box represents what is directly behind the Plume Box