NORTHERN SIERRA AIR QUALITY MANAGEMENT DISTRICT
RULE 421 - CONTRIBUTION TO VIOLATION OF NATIONAL AMBIENT AIR QUALITY STANDARD
(Adopted: September 11, 1991)
The Air Pollution Control Officer shall deny an Authority to Construct for a new facility or modification for which
an analysis was required and performed in accordance with the provisions of Rule 419 and which would contribute
to concentrations which exceed a national ambient air quality standard as of the new or modified facility's startup
date unless the following conditions are met:
- Each new source or modification within the facility shall meet an emission limitation which is equivalent to
the lowest achievable emission rate for such source and such nonattainment pollutant or precursor.
- The applicant shall certify that all existing major facilities owned or operated by the applicant in the State
of California are in compliance, or are on approved schedules or compliance with all applicable emission limitations
and standards which are part of the State Implementation Plan approved by the Environmental Protection Agency.
- Emission reductions (offsets) from existing facilities in the area of the new facility or modification shall
be secured pursuant to the provisions of Rule 411. The emission reductions shall be sufficient to provide
a net positive air quality benefit consistent with the provisions of the approved Nonattainment Plan.