AIR EMISSIONS REGULATIONS:

Air Quality Status	Serious and moderate nonattainment for PM (APCD includes all of Alpine, Inyo, and Mono counties) EPA's Nonattainment Areas
Major Source Threshold	70-100 tons of PM (depending on location) triggers NSR
Minor Source Permitting Exemption	IC engines with PTE less than 250 lb/day
Minor Source Treatment	BACT
Emergency Generating Limits	Case by case

DE MINIMIS EXEMPTIONS (Must meet 1298)

Internal combustion engines with a potential to emit less than 250 pounds per day of all criteria pollutants are exempt from permitting.

MINOR SOURCE PERMITTING

Units with a potential to emit 250 pounds per day of a criteria pollutant trigger BACT. The air district follows CARB's guidance for permitting of electric generating technologies which is available at. Sample BACT for control of NOx from turbines and internal combustion engines is as follows:

Size of Unit	Level of Control (ppm)
>3 MW	9
3-12 MW simple cycle	2.5
3-12 MW combined cycle	5
12-50 MW simple cycle	2.5
12-50 MW combined cycle	5
IC Engines	9

Units that don't trigger BACT may require controls on a case by case basis based on an impact analysis.

The entire permitting process takes less then 6 months.

TREATMENT OF EMERGENCY ENGINES

Emergency engines must obtain a permit. There are no rules specifically addressing these types of units. The air district may require timing retardation, a particulate trap on a diesel engine or an hourly limit. Units are allowed to operate during non-emergency situations as the air district determines.