MARIPOSA COUNTY AIR POLLUTION CONTROL DISTRICT
RULE 419 - NONATTAINMENT POLLUTANT AIR QUALITY ANALYSIS
- Utilizing the air quality simulation model designated pursuant to Rule 407, the Air Pollution Control Officer
shall determine the increases in ambient nonattainment pollutant concentrations in downwind District zones and
other Air Pollution Control Districts that will occur as a result of operation of the proposed facility or modification.
Also, the Air Pollution Control Officer may require that the cost of modeling be borne by the applicant. The model
shall consider air quality impacts projected for the area from source emissions and secondary emissions.
- Where a facility or modification is constructed in phases which individually do not emit more that 100 tons
per year of a nonattainment pollutant or precursor, the allowable emissions from all such phases granted an Authority
to Construct after December 21, 1976, shall be added together and this Rule shall be applicable when a proposed
phase would cause the sum of the allowable emissions to exceed 100 tons per year of such nonattainment pollutant
- For sources of nitrogen oxides, the initial determination of whether a facility or modification would cause
or contribute to a violation of the national ambient air quality standard for nitrogen dioxide shall be made using
the model designated pursuant to the provisions of Rule 407 and assuming that all nitric oxide emitted is oxidized
to nitrogen dioxide by the time the plume reaches ground level. The initial concentration estimates may be adjusted
by the Air Pollution Control Officer if adequate data are available to account for the expected oxidation rate.
- The determination as to whether a facility would cause or contribute to a violation of the national ambient
air quality standards shall be made as of the new or modified facility's startup date.