TUOLUMNE 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 than 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 or precursor.
- For sources of nitrogen oxides, the initial determination of whether such 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.