NORTHERN SIERRA AIR QUALITY MANAGEMENT DISTRICT
RULE 224 - EXISTING SOURCES
Adopted: September 11, 1991
In any case where Regulation II imposes standards different than the standards applicable to an existing source of emission (on day before adoption of new Regulation 1974), and the source of emissions was in compliance, under variance, or authority to construct, with the less restrictive standards applicable on such date, then the source shall remain in compliance with such Rule, until modified or until July 1, 1984, whichever occurs first. In no event is any modification to cause an increase in emissions over that being emitted prior to such modification.