NOx · Nitrogen oxides
The combustion pollutant that sets the air-permitting envelope for on-site generation; the cheapest NOx is the NOx never combusted, the next cheapest is abated by design.
Current numbers
5 ppmvd at 15% O₂US KKKKa NOx limit, concentration option: new gas turbines above 850 MMBtu/h at utilization above 45%
≤850 MMBtu/h / ≤24 consecutive mo / 25 ppm NOx at 15% O₂US KKKKa temporary-turbine subcategory: unit size cap, maximum consecutive stay at one site, and natural-gas NOx limit