Open burning causing excessive visible emissions is defined as opacity equal to or greater than what percentage?

Open burning causing excessive visible emissions is defined as opacity equal to or greater than what percentage?

• A. 20% opacity
• B. 30% opacity
• C. 50% opacity
• D. 40% opacity

Answer: (D)

Opacity is a measure of how much light is blocked by smoke in a plume. When open burning produces a plume that blocks about forty percent of the light, that is considered excessive visible emissions. This gives a clear, observable rule for deciding when a burn should be modified or stopped to reduce air pollution and protect safety. Plumes with less light blockage don’t meet the excessive-emissions criterion, while a higher threshold would allow more smoke before taking action. Forty percent provides a practical standard that is easy to apply in the field.

Opacity is a measure of how much light is blocked by smoke in a plume. When open burning produces a plume that blocks about forty percent of the light, that is considered excessive visible emissions. This gives a clear, observable rule for deciding when a burn should be modified or stopped to reduce air pollution and protect safety. Plumes with less light blockage don’t meet the excessive-emissions criterion, while a higher threshold would allow more smoke before taking action. Forty percent provides a practical standard that is easy to apply in the field.