The U.S. Environmental Protection Agency (EPA) recently announced new regulations that will implement a provision of the Clean Air Act known as the Good Neighbor Rule or interstate transport rule for the 2015 ozone National Ambient Air Quality Standard (NAAQS).
The so-called Good Neighbor rule requires the states to prohibit emissions that significantly contribute to the nonattainment of a NAAQS - or that interfere with the maintenance of those national health-based standards - in another downwind state.
EPA’s new regulations will impose new limits on emissions of oxides of nitrogen (NOx) from certain sources in Pennsylvania and 22 other states because NOx emissions contribute to the formation of ozone in downwind areas.
But let’s pause here to talk about why the EPA is concerned with NOx emissions and ozone in the first place.
Some Need-to-Know Info About NOx and Ozone & How They Harm Our Health
Nitrogen oxides are a mixture of gases composed of nitrogen and oxygen that are released to the air from the exhaust of motor vehicles, the burning of coal, oil, and natural gas. They are also produced commercially by reacting nitric acid with metals or cellulose. Nitrogen oxides are used in the production of nitric acid, lacquers, dyes, and other chemicals.
Nitrogen oxides break down quickly in the atmosphere by reacting with other substances found in the air. When they react with chemicals produced by sunlight it leads to the formation of ground-level ozone (more on ozone in a bit).
Low levels of nitrogen oxides in the air can irritate your eyes, nose, throat, and lungs, and could even cause coughing, shortness of breath, fatigue, and nausea. Breathing high levels of nitrogen oxides can cause rapid burning, spasms, and swelling of tissues in the throat and upper respiratory tract, reduced oxygenation of body tissues, a build-up of fluid in your lungs, and death.
Let’s get back to ozone: It forms when sunlight chemically reacts with pollutants emitted by cars, power plants, industrial boilers, chemical plants, refineries, and even some species of trees. And it can be harmful to your health, causing everything from throat irritation and coughing to chest pain and airway inflammation.
Ozone can even reduce lung function and harm lung tissue, and exposure can exacerbate conditions like asthma and other breathing issues. Some scientists have compared ozone-caused lung damage to sunburn.
Understanding the Good Neighbor Rule
Now that we understand the air pollutants of concern when it comes to the Good Neighbor Rule, let’s get into its nuts and bolts.
The first thing you need to know is that the EPA sets the bar for what emissions “significantly contribute” to the nonattainment relatively low: Sources in an upwind state need only to contribute emissions constituting 1% of the NAAQS threshold.
That means that, for the 2015 ozone standard, 0.70 parts per billion measured at an air quality monitor in a downwind state to trigger the rule. EPA performs a cost-benefit analysis to determine which sources in upwind states will need to reduce their NOx emissions - and by how much - to satisfy the Good Neighbor Rule’s requirements.
States that are home to sources subject to the Good Neighbor Rule are required to address its requirements in their State Implementation Plans due to EPA within three years of the promulgation or revision of a NAAQS.
Accordingly, Pennsylvania and the other 22 states should have submitted plans implementing the Good Neighbor Rule for the 2015 ozone NAAQS rule back in 2018.
This means that EPA waited more than four years to finally act after the states either failed to submit required plans (like Pennsylvania did) or submitted inadequate plans.
EPA’s Good Neighbor regulations focus on sources of NOx from just a few source types in certain industries:
Coal- and oil-burning electric generating units
Reciprocating internal combustion engines used in the pipeline transmission of natural gas
Cement kilns
Reheat furnaces in iron, steel, and ferroalloy mills
Furnaces used to produce glass
Solid waste incinerators and
Industrial boilers used in several industries, including iron, steel, and ferroalloy mills; paper and pulp mills; basic chemical manufacturing; and coal products manufacturing.
The new emission limits for EGUs in states where the “good neighbor” rule is triggered will be phased in using a trading program beginning this year. EPA expects that EGUs will be able to comply with the rule by optimizing control devices (typically, selective catalytic reducers) that are already installed. Sources affected by the new regulations that are not EGUs will have until 2026 to comply.
When the Good Neighbor Rule & RACT Collide
There's an interesting wrinkle, though: Major sources in Pennsylvania subject to the Good Neighbor Rule are also covered by what's known as Reasonably Available Control Technology III (RACT III) regulations that went into effect in Pennsylvania on Jan. 1. Although the two sets of regulations impose similar emission limits, they are not exactly the same, as this chart shows:
"The major sources subject to both rules might have to reduce their Nox emissions twice in the space of three years to stay in compliance," said GASP's Senior Attorney John Baillie. “This is a remarkably short time in the context of the air pollution laws. It shows EPA is taking ozone pollution seriously."