Measuring visible smoke from a chimney The Ringelmann (Ringlemann) chart is used to determine which parameter in stack emissions?

Introduction / Context:
Before sophisticated opacity meters became widespread, inspectors used simple visual standards to judge smoke emissions. The Ringelmann chart provides a reference scale of grey shades to estimate smoke density (opacity) from chimneys and stacks.

Given Data / Assumptions:

• Visual observation of stack plume against a contrasting background.
• Use of Ringelmann numbered shades (0 to 5).
• Objective: qualitative quantification of smoke density, not chemical composition.

Concept / Approach:
The Ringelmann chart correlates perceived darkness (opacity) of a plume to a number. It does not directly measure temperature, gas density, or mass concentration, though smoke density may relate indirectly to particulate loading. Inspectors compare the plume darkness to chart shades to report compliance with visible emission standards.

Step-by-Step Solution:

Verification / Alternative check:
Regulatory visible emission limits are often expressed as Ringelmann equivalent (e.g., “not to exceed Ringelmann 2 for more than X minutes per hour”).

Why Other Options Are Wrong:

• Combustibles in auto exhaust, gas density, temperature: Not measured by a visual greyscale.
• Particulate mass directly: Requires isokinetic sampling; Ringelmann is only an opacity estimate.

Common Pitfalls:
Assuming Ringelmann numbers equal particulate mass; relationships are site- and fuel-specific and not directly interchangeable.

Final Answer:
Smoke density from a chimney