GreenCalculus — US Supply-Chain GHG Emission Factors by NAICS-6 (EPA)

Supply-chain greenhouse gas emission factors for 1,016 US commodities in kg CO2eper 2022 US dollar of PURCHASER PRICE, from the EPA Supply Chain GHG EmissionFactors v1.3.0. Ranges from 3.924 for cement manufacturing to 0.029 for insurancebrokerage — a 135-fold spread, which means sector selection dominates aspend-based estimate far more than the precision of the spend figure. The 1,016 NAICS codes are a mapping, not 1,016 independent measurements. EPA'smodel runs on 386 USEEIO commodities producing only 281 distinct values, and thefactor is fully determined by the useeio_ref field carried on every row — acrossall 1,016 rows there is no case where two codes sharing a useeio_ref carrydifferent numbers. Around 80% of codes share their factor with at least onesibling: the three beef cattle codes all carry 2.893, and 21 codes resolve to asingle wholesale aggregate. Choosing a more specific NAICS code does not give youa more specific factor. Each commodity carries three figures: with margins (purchaser price, the headlinevalue), without margins (producer price), and the margin itself. 562 of the 1,016commodities carry a margin of exactly zero, because services are bought directlyand have no distribution chain; among the 454 that do carry one, the median is11.1% of purchaser price and the maximum is 56.7%. Match with-margins againstinvoice totals and without-margins against producer-price accounts. AR5 GWP-100 — EPA states "100-yr global warming potentials from IPCC 5th report(AR5)" for the v1.3 CO2e file. Note that v1.2 was published on AR4, so the basismoves between releases and should be re-checked rather than assumed. Electricity,government and household sectors are excluded by EPA: purchased electricity isScope 2 and belongs on a grid factor in kWh, not a dollar-denominated one. 2017NAICS vintage. Supports GHG Protocol Scope 3 Category 1 and 2 spend-basedestimation and PCAF data quality score 4. dollar-denominated one. 2017NAICS vintage. Supports GHG Protocol Scope 3 Category 1 and 2 spend-basedestimation and PCAF data quality score 4. Live page: https://greencalculus.com/data/us-supply-chain-ghg-emission-factors/API: https://greencalculus.com/wp-json/greencalculus/v1/us-supply-chain-factors