Previous Year Question
‘Ringelmann scale’ is used to measure density of
Smoke
Polluted water
Fog
Noise
Correct Answer: A
Detailed Solution
The Ringelmann Scale or Ringelmann Chart is used for the visual estimation of the apparent density/darkness or opacity of smoke emitted from a chimney or another emission source.
An observer compares the colour or darkness of the smoke with a standard chart. The darker and more opaque the smoke appears, the higher its Ringelmann value. CPCB also identifies the Ringelmann Scale as an early method of smoke measurement in which smoke darkness was visually compared with standard references.
The Ringelmann system is generally understood on a scale from 0 to 5—0 represents an almost clear/white condition, while 5 represents extremely dark/black smoke. Intermediate values represent progressively greater smoke darkness or opacity. The U.S. EPA describes it as a chart used for visual estimation of smoke density or light-obscuring capacity.
Historically, it has been used in monitoring combustion efficiency and visible emissions. Incomplete combustion may increase soot and carbonaceous particles, causing the exhaust plume to appear darker.