AIR EMISSIONS REGULATIONS:

Air Quality Status	In attainment (AQMD includes all of Mendocino 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
Emergency Generating Limits	50-100 hours for maintenance

DE MINIMIS EXEMPTIONS (Must meet 1298)

There are no permitting exemptions. Units may be exempted based on the discretion of the permitting officials.

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

Sources that do not trigger BACT are subject to a 20% opacity limitation and 0.1 grains of PM per cubic foot.

The entire permitting process must be complete in 60 days and generally takes between 2 weeks to 30 days.

TREATMENT OF EMERGENCY ENGINES

Emergency engines are permitted normally. These units are likely to receive an hourly operating limit between 50-100 hours per year for testing and maintenance, however there is no limit on hours of operation during actual emergencies. CARB Air Toxic Control Measures for Stationary Compression Engines apply (see the CA state page for more information).