APPENDIX TO POLICY

Air Permitting Emission Thresholds

Operating Permit and Permit Amendment Thresholds

Table 1. Air Emission Operating Permit Thresholds (tons/year)

Pollutant

Option D Registration Permit
(< value)

State Permit
(< value)

Federal Permit
(> value)

Carbon Monoxide (CO)

50

100

100

Nitrogen Oxides (NOx)

50

100

100

Sulfur Dioxide (SO2)

50

100

100

Particulate Matter (PM)

50

100

100

Particulate Matter < 10 microns (PM10)

50

100

100

Volatile Organic Compounds (VOC)

50

100

100

Lead

0.5

10

10

Combined Hazardous Air Pollutants (HAP)

12.5

25

25

Single HAP

5

10

10

Registration permit thresholds are based on actual emissions while other permits are based on "allowable" emissions, which are either potential emissions (8,760 hr/yr) or are calculated considering voluntary operating limits.

Table 2. Air Emission Permit Amendment Thresholds
 

Insignificant

Minor

Moderate/Major

Pollutant

lb/hr

lb/hr

lb/hr

Nitrogen Oxides (NOx)

< 2.28

2.28 – 9.13

9.13

Sulfur Dioxide (SO2)

< 2.28

2.28 – 9.13

9.13

Volatile Compounds (VOC)

< 2.28

2.28 – 9.13

9.13

Particulate Matter <10 microns (PM10)

< 0.855

0.855 – 3.42

3.42

Carbon Monoxide (CO)

< 2.28

5.70 – 22.80

22.80

Lead

< 2.28

0.025 – 0.11

0.11

Table 3 presents examples of the types of individual processes or equipment that may qualify for each amendment type:

Table 3: Air Emission Permit Amendment Thresholds

Equated to Table 1 by Equipment Type and Approximate Rated Throughput Guidance

 

Insignificant

Minor

Moderate/Major

Process/Equipment Type

Throughput

Throughput

Throughput

New Emergency Generators

< 200kw

<= 750kw

> 750kw

New Peak-Shaving Generators

n/a

n/a

ALL

Boilers – Natural Gas

< 10 MMBtu/hr

n/a

> 10 MMBtu/hr

Boilers – Distillate Oil

< 4.4 MMBtu/hr

4.4 – 10

> 10 MMBtu/hr

The preceding tables are provided only for guidance. Please contact DEHS and provide relevant data for final determination.

Construction Permit Thresholds (New Source Review)

The federal New Source Review (NSR) Program ensures that major projects (such as a new steam plant) undergo thorough review before permission to construct is granted. The NSR program affects only those projects that occur at a facility that is already a NSR major source (see column 1 of Table 4), or that, by adding new emission sources, will have potential emissions that exceed column 2 of Table 4. The Twin Cities campus is a NSR source. The other campuses are state-permitted facilities and are likely not going to become subject to the NSR program.

If a project will have a potential emission increase greater than those listed below (for any pollutant), a detailed review must be conducted to ensure that local ambient air quality will not be adversely impacted and that "best available control technology" is installed on new equipment. New Source Review can increase the permitting timeline by one year.

NSR can be avoided by accepting voluntary operating limits (hours or throughput) that would reduce increased annual emissions to less than the thresholds listed below.

Table 4. Air Emission NSR Construction Permit Thresholds (tons/year)

Pollutant

Modification of an Existing federal NSR Source

Existing State Source or
New Facility

Carbon Monoxide (CO)

100

250

Nitrogen Oxides (NOx)

40

250

Sulfur Dioxide (SO2)

40

250

Particulate Matter (PM)

25

250

Particulate Matter < 10 microns (PM10)

15

250

Volatile Organic Compounds

40

250

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