§ 11-7. Restrictions applicable to existing installations.

A. 

No person shall discharge into the atmosphere from any single source of emission whatsoever any air contaminant:

(1) 

Of a shade or density equal to or darker than that designated as No. 2 on the Ringelmann Chart, or

(2) 

Of such opacity as to obscure an observer's view to a degree equal to or greater than does smoke described in § 11-7A(1) of this regulation.

B. 

Discharge into the atmosphere from any single source of a shade or density greater than Ringelmann No. 2 shall be permitted for a period not to exceed two minutes and aggregating not more than four minutes per hour.