IMPERIAL COUNTY AIR POLLUTION CONTROL DISTRICT
RULE 401 - OPACITY OF EMISSIONS
(Adopted prior to 10/15/79; revised 11/19/85, 9/14/99)
This Rule applies to the discharge of pollutants into the Atmosphere.
No Person shall release or discharge into the Atmosphere from any single source of emission whatsoever, any Air Contaminant, other than uncombined water vapor, for a period or periods aggregating more than three (3) minutes in any hour which is:
B.1 As dark or darker in shade as that designated as No. 1 on the Ringlemann Chart, as published by the United States Bureau of Mines; or
B.2 Of such Opacity as to obscure an observer's view to a degree equal to or greater than does smoke described in subsection B.1. above,
B.3 Except that, for a any Source in operation prior to July 1, 1972 and which has been continuously subject to a valid permit to operate from the Air Pollution Control District, the "shade" or equivalent "Opacity" shall not exceed Ringlemann No. 2.
Exemptions to this Rule are identified in California Health and Safety Code Section 41701.5 (Diesel Pile Drivers), Section 41704 (Exemptions, to Prohibitions in Section 41701), Article 2 of Chapter 3 (Non- Agricultural Burning) Section 41800 et. seq., and Article 2 of Chapter 4 (Variances) Section 42350 et. seq., which are incorporated by reference.