Air pollution in your area may not always be caused by local sources – the transport of air pollution from upwind sources across state lines can also contribute to local air pollutant concentrations. Emissions of nitrogen oxides (NOx), specifically, can undergo reactions in the atmosphere to create ground-level ozone downwind of where the emissions are originally generated. US EPA’s “Good Neighbor Plan” for the 2015 Ozone NAAQS, issued as a final rule on March 15, 2023, is intended to address NOx emissions in 23 states to help curb downwind ozone concentrations in neighboring states.
Figure 1 identifies 23 states that were found to contribute at or above a threshold of 1% of the NAAQS in downwind states. (Source https://www.epa.gov/csapr/good-neighbor-plan-2015-ozone-naaqs)
The Good Neighbor Plan establishes rate-based and production-based limits to directly control emissions of NOx from power plants and industrial sources in states that significantly contribute to ground-level ozone concentrations in downwind states. Figure 2 identifies states covered by Good Neighbor provisions for power plants and other industries (Source https://www.epa.gov/csapr/good-neighbor-plan-2015-ozone-naaqs).
The new rule implements a new cap-and-trade program and sets state budgets based on emissions reductions from power plants. It also sets initial control stringency based on the level of reductions achievable through immediately available measures, including consistently operating emissions controls already installed at power plants.
For the first time, this rule goes beyond power plants, regulating cross-state air pollution from new and existing non-electric generating units (non-EGUs) at industrial sources as well. The applicability criteria for non-EGU industries and associated emission limits are shown in Table 1:
Table 1 Applicability Criteria and Emissions Limits for Non-EGUs
| Industry | Emission Unit Type | Applicability Requirements | Emission Limits |
| Pipeline Transportation of Natural Gas | Reciprocating Internal Combustion Engines | Nameplate rating of >1000 braking horsepower (bhp) | Four Stroke Rich Burn: 1.0 g/hp-hr Four Stroke Lean Burn: 1.5 g/hp-hr Two Stroke Lean Burn: 3.0 g/hp-hr |
| Cement and Concrete Product Manufacturing | Kilns | Directly emits or has the potential to emit 100 tpy or more of NOx | Long Wet: 4.0 lb/ton Long Dry: 3.0 lb/ton Preheater: 3.8 lb/ton Precalciner: 2.3 lb/ton Preheater/Precalciner: 2.8 lb/ton |
| Iron and Steel Mills and Ferroalloy Manufacturing | Reheat Furnaces | Directly emits or has the potential to emit 100 tpy or more of NOx | Test and set limit based on installation of Low-NOx Burners |
| Glass and Glass Product Manufacturing | Furnaces | Directly emits or has the potential to emit 100 tpy or more of NOx | Container Glass Furnace: 4.0 lb/ton Pressed/Blown Glass Furnace: 4.0 lb/ton Fiberglass Furnace: 4.0 lb/ton Flat Glass Furnace: 7 lb/ton |
| Iron and Steel Mills and Ferroalloy Manufacturing Metal Ore Mining Basic Chemical Manufacturing Petroleum and Coal Products Manufacturing Pulp, Paper, and Paperboard Mills | Boilers | Design capacity of >100 mmBtu/hr burning coal, oil, or gas | Coal: 0.20 lb/mmBtu Residual Oil: 0.20 lb/mmBtu Distillate Oil: 0.12 lb/mmBtu Natural Gas: 0.08 lb/mmBtu |
| Solid Waste Combustors and Incinerators | Combustors or Incinerators | Design capacity >250 tons of waste/day | 110 ppmvd on a 24-hour averaging period 105 ppmvd on a 30-day averaging period |
The compliance date for non-EGU requirements is May 1, 2026, with an option to request 1-year compliance extensions in certain circumstances, as long as the request is submitted at least 180 days prior to the compliance deadline.
Based on information received by US EPA during the public comment period, several important adjustments were made to proposed sources and emission limits included in the rule. Some of the changes made include:
- Pipeline Transportation of Natural Gas:
- The applicability criteria were adjusted to exclude emergency engines.
- A case-by-case option for facility-wide emissions averaging plans was added.
- Cement and Concrete Product Manufacturing:
- The daily NOx source cap limit was removed, which could have resulted in artificially restrictive NOx emissions limits for cement kilns due to lower operating periods resulting from the COVID-19 pandemic.
- Iron and Steel Mills and Ferroalloy Manufacturing:
- Proposed requirements for units other than reheat furnaces (blast furnaces, blast oxygen furnaces, electric arc furnaces, etc.) were removed.
- Glass and Glass Product Manufacturing:
- Alternative requirements for startup, shutdown, and idling conditions were included.
- Boilers:
- A low-use exemption was added, but temporary boilers were still included in the final rule.
- Applicability criteria were adjusted to exclude recovery boilers and process heaters.
US EPA estimates the Good Neighbor Plan will reduce NOx emissions from the 23 significantly contributing upwind states by approximately 70,000 tons during the 2026 ozone season (May 1 through September 30), with about 25,000 tons coming from fossil-fueled power plants and 45,000 tons from other covered industrial sources.
The final rule has not yet been published in the Federal Register but will become effective 60 days after its publication.
To learn more, contact Sr. Compliance Specialist, Katie Milk, CHMM, CEA.
