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The Combined Air Emissions Reporting (CAER) project seeks to streamline the way industry reports air emissions to meet EPA, state, local, and tribal program requirements. The CAER System (CAERS) is an electronic reporting application that allows facilities to report to more than one program via a single data submission.


Various federal, state, local, and tribal programs require industry to report air pollutant emissions to separate systems at different times of the year to meet requirements for the following programs: the National Emissions Inventory (NEI), the Toxics Release Inventory (TRI), the Greenhouse Gas Reporting Program (GHGRP), the Compliance and Emissions Data Reporting Interface (CEDRI), and partner-specific systems. This leads to duplication of effort for both industry and government. While each program collects different data, shared data could be reported just once for use across multiple programs.


Combined emissions reporting will reduce redundancy in reporting air emissions and associated facility data, as well as review time for EPA, state, local, and tribal programs on data quality assurance and data reconciliation among programs. In 2021, facilities will be able to use the CAER System (CAERS) to report inventory year 2020 data to support their state, local, tribal, NEI, and TRI reporting. This will benefit the following stakeholders:

  • Regulated Community: CAER will decrease the reporting burden for facilities by reducing duplicative data entry across programs and improving both the reporting experience and efficiencies.
  • Public: CAER will improve data availability, timeliness, transparency, consistency, and quality for users.
  • Regulators: EPA, states, tribes, and local governments will spend less time reviewing, compiling, and reconciling data, and the most timely and high-quality data will be available to decisions makers.


CAER partnered with the Georgia Department of Natural Resources (DNR) and 12 of its regulated facilities to develop and pilot the “Common Emissions Form,” now known as CAERS. The first version of CAERS was released in April 2020 and was used for Georgia DNR’s 2019 NEI reporting cycle. Using CAERS, Georgia DNR was able to submit its point source NEI data one month earlier than in previous years.

CAERS Version 2 deployed in March 2021 for the NEI 2020 reporting cycle and is being used by more than 300 facility reporters in Georgia and by the District of Columbia Department of Energy and Environment, and the local authorities of Pima, Arizona, and Lincoln-Lancaster, Nebraska. Shared air toxics data reported there are also available for industry use in reporting air emissions to TRI.

CAERS is currently adding new partners and several state, local, and tribal agencies have CAERS test accounts to explore their needs as they consider onboarding with CAERS. Future work includes building out this new functionality with partners, as well as designing and building out shared data workflows with CEDRI and GHGRP.


  • Build additional CAERS functionality to meet new NEI program requirements and refine the data that can be made available to TRI.
  • Establish data workflows with CEDRI and GHGRP.
  • Work with partners from Arizona, Minnesota, Montana, and Rhode Island.
  • Develop several shared services to support CAERS. These services will also be available as stand-alone products for use by state, local, and tribal partners not using CAERS.


For more information, please visit the CAER Project Website. To join the CAER listserv, send an email to


CAER Fact Sheet

State/Local/Tribal (SLT), National Emission Inventory (NEI), Toxic Release Inventory (TRI) Mapping

Research consistency and possible workflows for sharing of emissions data between TRI, SLTs and NEI. This will include creating a crosswalk for pollutants between programs, figuring out how to handle each program’s terminology (e.g. facility, unit) and emission sources covered by reporting, and identifying where guidance needs to be harmonized, among other things.

Phase 1 – Final Report

TRI/NEI Pollutant Crosswalk

Quality Assurance / Quality Control (QA/QC)

Identification and evaluation of a common set of emissions data QA/QC procedures for potential use in a shared emission reporting system.

Phase 1 – Final Report

Data Model for the Common Emissions Form (CEF)

Document a data model with the emissions-related data elements needed to support a common emission form (CEF) reporting structure in a shared emissions platform. Identify and include state-specific data elements sufficient to allow for broad usage by states and EPA CAER

Phase 1 – Final Report

Appendix A – Data Model Survey Results

Appendix B – Additional Pollutants

Appendix C – Additional Data Fields

SCC-WebFIRE for the Common Emissions Form (CEF)

Scoping study for identifying problems and solutions with SCCs and WebFIRE that will meet SLT, NEI, NATA, and CEDRI/ERT requirements under the CAER project.

Phase 1 – Final Report

State Greenhouse Gas Reporting Program (GHGRP) to National GHGRP Mapping

This will be a pilot study to map emission data in the national GHGRP to state GHGRP programs. The goal of the study is to understand which data elements state mandatory reporting programs have in common with GHGRP required data elements. This will help us understand what would be necessary to share data between the programs.

Phase 1 – Final Report

Appendix A – GHG PDT Dad Element Comparison