Air emissions inventories catalog emission sources and quantify key air pollutant emissions for air quality planning and modeling for, among other purposes, SIP requirements for ozone, fine particulates, and regional haze to meet the Clean Air Act requirements.
MARAMA began coordinating the development of regional inventories in 1998 and continues to be integral to inventory development as part of national collaborations of US EPA, state, tribal, and MJO staff. During this time MARAMA developed tools and expertise for projecting future years and control strategies from base year inventories, allowing the nimble changing of both base and projection years and accommodating changing priorities.
The hallmark of MARAMA inventories is working with agency staff, providing a peer community for learning and collaborating and providing MARAMA with a wealth of information for continuous emissions inventory improvements. This work happens regionally in the monthly Northeast Regional Emissions Inventory (EI) Leads Workgroup and nationally in the various Collaborative workgroups.
For more information on MARAMA’s emissions inventory development or to obtain current or past inventory files, please contact Susan McCusker at smccusker@marama.org.
The EI Leads Workgroup is a monthly meeting that provides MARAMA and northeast state and local air agency staff a forum for: discussing emissions inventory topics such as technical and policy aspects of EI development and impacts of changes to EI methodologies, working with other groups such as Ozone Transport Commission (OTC) modelers and EPA staff, conducting remote EI training, and engaging in special breakout discussions as needed. In addition, the workgroup reviews and provides important feedback on regional growth factor development, Collaborative inventory efforts, and the National Emissions Inventory (NEI) leading more complete and robust inventories for regional planning an SIP needs.
An Emissions Modeling Platform (EMP) is developed periodically to serve as a basis for national, regional, and local modeling for regulatory analyses and State Implementation Plan (SIP) development. Following the success of the 2016 Emissions Modeling Platform (2016 EMP), when it was time to consider a new base year and new analytic years, the U.S. EPA, multi-jurisdictional organizations (MJOs), states, local, and tribal air agencies again came together in a collaborative effort to develop the 2022 EMP. The 2022 EMP includes 2022v1 with the 2022 base year and 2026 analytic year and 2022v2 with the 2022 base year.
The 2022 Emissions Collaborative (2022EC) was structured around workgroups organized by emission inventory sectors. The Electric Generating Unit (EGU) sector offers two options for projected analytic year emissions: Eastern Regional Technical Advisory Committee (ERTAC) and U.S. EPA Integrated Planning Model (IPM). The Mid-Atlantic and Northeast states, as well as others throughout the country, use ERTAC EGU emissions to support air quality attainment demonstrations and for SIP development.
In considering base years, the 2022EC ruled out the 2020 and 2023 national emissions inventories (NEIs) for being, respectively, an unrepresentative baseline due to impacts from the COVID-19 pandemic and too late for some air quality modeling needs. Eliminating 2020 and 2023, the Collaborative next looked at 2021 and 2022. 2022 had the advantages over 2021 of being more recent and having ozone-conducive meteorology over most of the country. Not being an NEI year, however, meant that full emissions reporting was not required for 2022 so 2022 emissions were based on the 2020 NEI with adjustments applied for several sectors. The 2022EC then developed growth and control factors for projecting the base year to analytic years with MARAMA taking a leading role in the effort to develop growth factors for the analytic year projections.
Files and documentation for the 2022 EMP are available here: https://views.cira.colostate.edu/wiki/SiteSettings/Wiki/Index/11209
For more information on the ERTAC EGU platform option, contact Susan McCusker (smccusker@marama.org)