Review of the Bureau of Ocean Energy Management "Air Quality Modeling in the Gulf of Mexico Region" Study

Emissions from activities in the Gulf of Mexico Region (GOMR)—including emissions associated with oil and gas exploration, development, and production on the Gulf waters—can result in increased levels of air pollutants that contribute to a range of air quality impacts in the region. Carbon monoxide, lead, nitrogen dioxide, ozone, particulate matter (PM), and sulfur dioxide, also known as “criteria air pollutants,” are considered harmful to public health and the environment. In recognition of the potential adverse impacts, the Environmental Protection Agency (EPA) sets standards, called the National Ambient Air Quality Standards (NAAQS), for those pollutants. The Bureau of Ocean Energy Management (BOEM) manages the U.S. outer continental shelf (OCS) oil and gas resources and is required to help manage air quality in the GOMR to comply with the NAAQS. BOEM meets these requirements in part by conducting air pollution dispersion and photochemical modeling, and analyzing the results to estimate the individual and cumulative impacts of offshore oil and gas exploration, development, and production activities. Such analyses are used to set limits on emissions. If these analyses indicate that an offshore oil and gas facility adversely impacts the air quality of any state, then that OCS facility is subject to regulations and emissions controls to ensure compliance with the NAAQS. BOEM’s air quality analyses for the GOMR had not been updated in decades when in 2014, BOEM asked a team of contractors to conduct the Air Quality Modeling in the Gulf of Mexico Region Study (the “Study”). The Study will likely lead to regulatory changes, potentially including new emission exemption thresholds (EETs). EETs are a screening tool that take into account distance from shore and projected annual emission estimates in exploration, development, and production plans by potential lessees and operators to determine if more refined air quality modeling and emission controls are needed. The current EETs were developed in the 1980s and do not reflect more recently regulated pollutant (i.e., PM_2.5 and PM₁₀) and updated (i.e., 8-hour-average ozone, 1-hour-average NO₂ and SO₂) air quality standards, nor state-of-the-science dispersion and photochemical modeling approaches. BOEM designated the Study as “highly influential” because of the potential impact on EETs and the associated methods, the development of a long-term meteorological dataset for future analysis, and the assessment of potential air quality impacts. As a result, BOEM asked the National Academies of Sciences, Engineering, and Medicine (the National Academies) to provide an independent technical review of the Study. The National Academies Board on Atmospheric Sciences and Climate appointed an ad hoc committee to conduct this review (see Chapter 1 for the full statement of task)¹.