GREAT BASIN UNIFIED AIR POLLUTION CONTROL DISTRICT
RULE 400 - RINGELMANN CHART
(Adopted 9/05/74; Revised 1/18/79)
A person shall not discharge into the atmosphere from any single source of emission whatsoever, any air contaminant for a period or periods aggregating more than three minutes in any one hour which is:
- "An observer" is defined as either a human observer or a certified, calibrated, in-stack opacity monitoring system.