This dataset contains characterization factors (CFs) for the five mandatory life cycle impact assessment (LCIA) categories required in ISO 21930:2017: 1. Greenhouse gases (GHG), which is incorrectly named ‘GWP’ in the standard, 2. Ozone Depletion Potential (ODP), 3. Eutrophication Potential (EP), 4. Acidification Potential (AP), and 5. Photochemical Ozone Formation Potential (POCP) These CFs are appropriate for use with life cycle inventory data for activities occurring within the United States. The short name for the dataset is ISO21930-LCIA-US v0.1. The characterization factors, with the exception of GHGs, are identical to the those currently in TRACI v2.1 for the corresponding impact categories. The four TRACI v2.1 impact categories have the same names as ISO 21930:2017 with the exception of POCP, which is called “smog formation” in TRACI v2.1. The characterization factors for GHGs are the 100-year (GWP-100) GWPs from the International Panel for Climate Change (IPCC)’s 5th Assessment Report (AR5) report. The names for the chemicals, release contexts, units and IDs are from the Federal LCA Elementary Flow List (FEDEFL) v1.2. These datasets were created using the LCIA Formatter v1.1.2 (https://github.com/USEPA/LCIAformatter). Formats Datasets are provided in simple tables in Excel, in the openLCA JSON-LD format using Federal LCA Commons standards, and in Apache parquet format. The fields in the Excel and identical parquet versions use the LCIAmethod format fields: https://github.com/USEPA/LCIAformatter/blob/master/format%20specs/LCIAmethod.md 1. Zip archives of JSON files in the JSON-LD schema: a file type associated with the openLCA schema. Two JSON-LD versions are provided. a. “ISO21930-LCIA-USv0.1_noflows_json-ld.zip” is without flow objects. b. “ISO21930-LCIA-USv0.1_wprefflows_json-ld.zip” is with flow objects of preferred flows from the FEDEFL. See usage notes below. 2. Excel and parquet: tabular format according to schema from the LCIA formatter, with additional fields added: o “source_method”: indicates the original method source for the indicator (e.g., TRACI 2.1 or IPCC) o “source_indicator”: indicates the name of the indicator in its original form (e.g. Smog Formation) o “category”: indicates the desired parent folder name for the impact category (shown as “EPA EPD in Figure 1) Usage Generally, in all formats, the CFs can be multiplied by kg (or unit specified in the denominator) of the relevant chemical emitted to calculate the potential impact value for a given impact category for that relevant chemical. If no CF exists for a chemical in a given impact category, it is not considered to have an impact in that category. The parquet format is most efficient for import into applications or scripts using languages like Python and R. The Zip archives of JSON-LD files can be loaded into openLCA or other LCA or EPD software supporting that format. When loaded into openLCA (via JSON-LD), the method shows as a separate impact assessment method. Individual indicators are categorized within the EPA EPD category. For introduction to importing a dataset into openLCA we recommend this training video from the National Renewable Energy Laboratory. https://youtu.be/YLao5jC5b_0?si=H0SNZ_ufOwInkgCF&t=48 The version with no flows is designed to import in a database that already has FEDEFL elementary flows or no more modeling is to be done that would use any new flows. It will only create the LCIA method. The version with flows can be imported into a new ‘empty’ database and it will create not just the LCIA method but all associated flows and more basic objects like units and flow properties. It can be used when no process data that you wish to model has been created yet and/or if you want to have a full import of all relevant elementary flows.