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APEN and permit threshold table

The following table lists APEN and permit threshold limits for pollutants in Colorado. VOCs and NOx are considered precursors to ozone and therefore businesses in the 8-hour ozone nonattainment area must report at the nonattainment thresholds for those pollutants. All other pollutants are reported at the attainment thresholds. The 8-hour ozone nonattainment area currently consists of the following counties:
  • Adams
  • Arapahoe
  • Boulder (including most of Rocky Mountain National Park)
  • Broomfield
  • Denver
  • Douglas
  • Jefferson
  • Weld
  • and a portion of Larimer (see ozone nonattainment map).

Ozone nonattainment map 

APEN and Permit Reporting Thresholds

for Attainment and Nonattainment Areas

 Calendar Year Uncontrolled Actual Emissions
APEN ThresholdsPermit Thresholds1
PollutantAttainmentNonattainmentAttainmentNonattainment

VOCs

(Volatile Organic Compounds)

2 tons1 ton5 tons2 tons

PM-10

 

2 tons

---2

5 tons

---2

PM-2.5

 

2 tons

---2

5 tons

---2

TSPs

(Total Suspended Particulates)

2 tons

---2

10 tons

---2

CO (Carbon Monoxide)

 

2 tons

---2

10 tons

---2

SOx (Sulfur Dioxide)

 

2 tons

---2

10 tons

---2

NOx (Nitrogen Oxide)

 

2 tons1 ton10 tons5 tons

Other Criteria Pollutants3

 

2 tons

---2

2 tons

---2

Pb (Lead)

 

100 pounds

---2

200 pounds

---2

HAPs

(Hazardous Air Pollutants)

250 pounds

---2

N/AN/A

1These thresholds are for equipment from the entire facility (total facility uncontrolled actual emissions from all sources above APEN thresholds for this pollutant), and not just one individual piece of equipment.

2Colorado does not have an existing nonattainment area for this pollutant and utilization of the attainment area thresholds is appropriate.

3Other criteria pollutants: fluorides, sulfuric acid mist, hydrogen sulfide, total reduced sulfur, reduced sulfur compounds, and municipal waste incinerator emissions.