Ringelmann chart

{
  "id": "MLC-T-CHM-010361",
  "term": "Ringelmann chart",
  "field": "Chemistry",
  "definition": "A series of charts used to visually estimate the density of smoke emitted from industrial sources, such as chimneys. Each chart consists of a grid of black lines on a white background, with varying line thickness and spacing to represent different levels of smoke opacity. The charts are typically held at a specific distance from the observer and compared to the smoke plume to assign a Ringelmann number from 0 (no smoke) to 5 (100% opaque).",
  "subject": "Chemistry and the Environment",
  "see_also": [
    "air pollution",
    "smoke"
  ],
  "references": [
    "PAC, 1990, 62, 2167. 'Glossary of atmospheric chemistry terms (Recommendations 1990)' on page 2211 (https://doi.org/10.1351/pac199062112167)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/ringelmann-chart/"
}