22.8.1 Overview
Determining whether a project requires an air construction permit can be complex and will vary depending upon the local air quality regulations. To do this evaluation properly, there is no substitute for detailed knowledge and understanding of these local air quality regulations. However, I put together the following flowchart to assist when evaluating whether an air construction permit is required for a project:
22.8.1 Mobile Sources
Some mobile or portable sources (e.g., electrical generators) may be exempt from the air permitting requirements if the sources are non-road engines or the sources are engines used to propel vehicles such as the following: “self-propelled (tractors, bulldozers), propelled while performing their function (lawnmowers), portable or transportable (has wheels, skids, carrying handles, dolly, trailer or platform). Note: a portable non-road engine becomes stationary if it stays in one location for more than 12 months (or full annual operating period of a seasonal source)[1]”. This exemption is for the combustion emissions and not other emissions that might be generated by mobile equipment, while at a stationary site. For example, a facility that uses a truck-mounted grinder that generates particulate emissions from the grinding operation might have to include the particulate emissions in its emissions calculations, but not the truck’s engine emissions.
22.8.2 Fugitive
Although state regulations may vary, a facility is typically not required to consider fugitive emissions, such as storage piles and haul roads, towards permitting thresholds, unless the facility is subject to a New Source Performance Standards or it facility belongs to one of the following categories of industries:
- Coal cleaning plants (with thermal dryers)
- Kraft pulp mills
- Portland cement plants
- Primary zinc smelters
- Iron and steel mills
- Primary aluminum ore reduction plants
- Primary copper smelters
- Municipal incinerators capable of charging more than 50 tons of refuse per day
- Hydrofluoric, sulfuric, or nitric acid plants
- Petroleum refineries
- Lime plants
- Phosphate rock processing plants
- Coke oven batteries
- Sulfur recovery plants
- Carbon black plants (furnace process)
- Primary lead smelters
- Fuel conversion plants
- Sintering plants
- Secondary metal production plants
- Chemical process plants – The term chemical processing plant shall not include ethanol production facilities that produce ethanol by natural fermentation included in NAICS codes 325193 or 312140
- Fossil-fuel boilers (or combination thereof) totaling more than 250 million British thermal units per hour heat input
- Petroleum storage and transfer units with a total storage capacity exceeding 300,000 barrels
- Taconite ore processing plants
- Glass fiber processing plants
- Charcoal production plants
- Fossil fuel-fired steam electric plants of more than 250 million British thermal units per hour heat input[2].
22.8.3 Exempt Emission Types
A state environmental agency may exempt certain emission sources. These generally are not large emissions sources and this list sometimes overlaps with the mobile sources and emissions below certain thresholds (Section 22.8.4). You will need to review the state’s construction permit regulations to identify this list and they typically vary from state to state.
22.8.4 Emissions Below Certain Thresholds
Each state typically has an emissions threshold below-which the emission source does not need a construction permit. These thresholds are typically potential annual emissions with different thresholds for each pollutant, but they may also be hourly potential emissions and/or actual emissions.
22.8.5 References
[1] “Understanding the Stationary Engines Rules” Environmental Protection Agency website (https://www.epa.gov/stationary-engines/understanding-stationary-engines-rules) accessed January 7, 2023.
[2] 40 CFR 51 Appendix S II.F.
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