AIR EMISSIONS REGULATIONS:

Air Quality Status	In attainment (APCD includes all of Colusa County) EPA's Nonattainment Areas
Major Source Threshold	250 tons of any criteria pollutant triggers PSD
Minor Source Permitting Exemption	None
Minor Source Treatment	BACT or NOx and opacity limits
Emergency Generating Limits	200 hours per year

DE MINIMIS EXEMPTIONS (Must meet 1298)

Exemptions may be made on a case by case basis at the discretion of the permitting official.

MINOR SOURCE PERMITTING

All units with a potential to emit greater than 25 pounds per day of a criteria pollutant will be required to apply BACT. 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

Units that do not trigger BACT are likely to have a NOx emission limit of 640 ppm if burning natural gas and 700 ppm if burning diesel. There is also a 40% opacity limit and. In addition pipeline grade natural gas or CARB certified diesel must be used.

The entire permitting process generally takes about 1 week, but could be longer.

TREATMENT OF EMERGENCY ENGINES

Emergency engines are likely to be exempted operating less than 200 hours per year for maintenance and testing and during emergencies only. CARB Air Toxic Control Measures for Stationary Compression Engines apply (see the CA state page for more information).