AIR EMISSIONS REGULATIONS:

Air Quality Status	Moderate nonattainment for ozone and PM (AQMD includes all of Butte County) EPA's Nonattainment Areas
Major Source Threshold	100 tons of NOx, VOCs or PM triggers NSR
Minor Source Permitting Exemption	Less than 50 hp or 250 hp and operating less than 200 hr/yr
Minor Source Treatment	BACT
Emergency Generating Limits	Case by case

DE MINIMIS EXEMPTIONS (Must meet 1298)

Engines less than 250 hp and operating less than 200 hours per year (excluding diesel) or less than 50 hp are exempt from permitting.

MINOR SOURCE PERMITTING

All units with a potential to emit greater than the following are required to do BACT:

Pollutant	Potential to Emit (lb/day)
CO	137
NOx	50
PM-10	80
VOC	50
SOx	80

The air district follows CARB's guidance for permitting of electric generating technologies. 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

There is also a toxics requirement. Under this requirement sources are subject to a site specific evaluation of potential adverse health effects to determine whether or not a permit can be issued. Units that do not trigger BACT will have a 0.02% fuel sulfur limit and a 40% opacity limit. No additional controls will be required.

TREATMENT OF EMERGENCY ENGINES

Emergency engines will receive a permit that limits them to operate only during emergencies and maintenance. An hourly limit for maintenance will be based on safety risks and the unit's potential to emit and it will generally be between 50-200 hours per year.