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Emission Inventories and Projections

Emission Inventories and Projections

Emission Inventories and Projections

Emission inventories and projections serve as the foundation for understanding the causes of existing air quality problems and for evaluating potential solutions. They can help us understand the types of changes needed to reduce the impacts of climate change. SC&A staff have been preparing emission inventories for three decades and have actively supported EPA, states, regional, and local agencies in implementing and complying with the Clean Air Act Amendments and federal, state, and local air pollutant and climate change regulations.

Examples of emission inventory services we provide:

  • Multipollutant inventories including criteria pollutants, air toxics, and greenhouse gases and all anthropogenic emission sectors
  • Emission inventory support for meeting SIP, transportation conformity, NEPA, and other regulatory requirements
  • Application of EPA-approved emission models, including MOVES for onroad and nonroad mobile emission sources
  • Use of the Federal Aviation Administration’s Emission Dispersion and Modeling System (EDMS) for modeling aircraft and airport-related emissions
  • Activity and emissions forecasting
  • Developing emission inputs to air quality models
  • Analysis of emission control technologies, measures, and strategies
  • Development of emission inventory tools
  • Spatial and temporal resolution of inventories
  • Use of GIS-based data in inventory development
  • Energy mix and fuel consumption analyses

Sample Projects

Maritime Emission Inventories. The U.S. Coast Guard was interested in having a model that captured GHG and criteria pollutant emissions from all vessel activity in U.S. waters in order to evaluate new or potential regulatory actions, perform alternative scenario analyses, and perform research projects. SC&A developed a modeling approach that could achieve these goals and applied the developed approach in preparing vessel emission inventories covering three large geographic areas with significant port activity, validating the model concepts. The inventories were built from AIS vessel movement data, covering all AIS-enabled vessels in the selected areas while at berth and in transit. Several emission reduction scenarios were evaluated. Maureen Mullen of SC&A delivered a presentation on this project at the 2018 AWMA Annual Conference.

Yuma Emission Inventory. SC&A developed a PM10 emission inventory for Yuma, Arizona. A key to the success of this project was obtaining significant local data provided by stakeholders and developing tailored emission calculation methods for significant source categories, based on the latest research.

Project-Level Air Quality Studies. SC&A supported a state DOT in preparing air quality hot spot analyses needed to fulfill NEPA and Clean Air Act conformity requirements for five major road projects in a major metropolitan area. Tasks performed by SC&A included: CO screening hot spot analyses, quantitative Mobile Source Air Toxics (MSAT) hot spot analyses, CAL3QHC dispersion modeling of CO, and developing the MSAT affected road network.

National Emission Inventory. SC&A staff have supported the development of EPA’s National Emission Inventory. This includes development of the onroad and nonroad emission inventories, development of tools for use by state and local agencies in preparing non-point emission inventories, and related inventory development.

State-Level GHG Inventories. SC&A staff developed GHG base case emissions and projections for about 20 states covering all emission sectors. For many of these states, SC&A also evaluated potential GHG mitigation measures being considered as part of state climate action plans, including analysis of GHG emission benefits, potential multipollutant co-benefits, and the costs of the measures.

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