VOC Potential to Emit and Nonattainment NSR
A commercial printing facility proposes to install a new sheet-fed press in a severe ozone nonattainment area where the major-source threshold for VOC is 25 tons per year. The press will use 12,000 gallons per year of solvent-based ink containing 45% VOC by weight (density 8.0 lb/gal) and 2,000 gallons per year of cleanup solvent that is 100% VOC (density 6.5 lb/gal). No add-on control device is proposed. The facility will also install a 10 MMBtu/hr natural gas-fired dryer with potential NOx emissions of 1.6 tpy. The company wants to know whether it needs a major nonattainment New Source Review (NSR) permit, and whether it can avoid that permit by accepting a lower VOC limit. The state has adopted the federal nonattainment NSR rules, including LAER and offsets. The facility has no existing VOC emission reductions available on-site.
1. Calculate the potential VOC emissions from the ink and cleanup solvent in tons per year. Is the facility a major source for VOC under the severe ozone nonattainment threshold?
Read the worked answer
Use the annual material usage, density, and VOC weight fraction; assume all VOC in the material is emitted because no control device is proposed.
Ink:
- 12,000 gal/yr × 8.0 lb/gal = 96,000 lb/yr
- VOC = 96,000 × 0.45 = 43,200 lb/yr
- 43,200 ÷ 2,000 lb/ton = 21.6 tpy
Cleanup solvent:
- 2,000 gal/yr × 6.5 lb/gal = 13,000 lb/yr
- VOC = 13,000 × 1.00 = 13,000 lb/yr
- 13,000 ÷ 2,000 = 6.5 tpy
Total VOC PTE = 21.6 + 6.5 = 28.1 tpy.
The severe ozone nonattainment major-source threshold is 25 tpy VOC, so the facility would be a major source for VOC at 28.1 tpy. The 1.6 tpy NOx from the dryer is below the 25 tpy NOx major-source threshold, so NOx alone does not make the facility major. The VOC calculation is the controlling issue.
2. What nonattainment NSR requirements apply, and how many tons of VOC offsets would be needed at a 1.3:1 ratio? Does PSD apply?
Read the worked answer
Because the new facility would be a major VOC source in a severe ozone nonattainment area, nonattainment NSR applies. The applicant must install LAER for VOC and obtain emission offsets that are surplus, permanent, quantifiable, and enforceable. In a severe area, the offset ratio is typically 1.3:1.
Offsets needed: 28.1 tpy × 1.3 = 36.5 tpy of VOC offsets. The offsets must generally be obtained in the same nonattainment area or an area with equal or higher ozone classification, and they must not be required by another applicable requirement.
PSD does not apply to the VOC emissions because the source is major in a nonattainment area and nonattainment NSR governs. PSD could apply to another pollutant if the facility were major for that pollutant and significantly increased it, but the given NOx PTE of 1.6 tpy is far below the major-source and significance thresholds. The facility would also likely need a title V permit after construction.
3. The company wants to accept an enforceable VOC limit to stay below major-source status. What limit would you recommend, and what permit terms would make it enforceable?
Read the worked answer
Recommend a total VOC limit below 25 tpy with a margin for calculation and operational variability, such as 24.0 tpy on a 12-month rolling basis. That requires reducing the calculated 28.1 tpy by about 4.1 tpy, through lower-VOC inks, a control device, or a production/material-use cap.
Enforceable terms should include:
- A permit condition limiting total VOC emissions to 24.0 tpy, calculated as a 12-month rolling sum.
- Recordkeeping of monthly ink and cleanup-solvent usage, VOC content, and density.
- A specified emission calculation method using the same mass-balance approach.
- Monthly or quarterly reporting, with prompt notification if the rolling total approaches the limit.
- A prohibition on using uncontrolled higher-VOC materials without a permit modification.
- A production or material-use cap if needed to make the limit practically enforceable.
The limit must be federally enforceable and included in the permit as a synthetic minor condition. If the facility cannot reliably stay below the limit, it should plan for nonattainment NSR, LAER, and 36.5 tpy of offsets.