Documentation

Indicators and units

CTUe and CTUh are comparative toxic units for ecosystems and humans (USEtox). Value added and jobs are economic outputs, not environmental impacts.

Air emission flows

The "Air emission flows" category reports individual emissions: sulfur dioxide, nitrogen dioxide, carbon monoxide, carbon dioxide, methane, lead to air, particulate matter ≤ 2.5 µm and 2.5–10 µm. Total includes the supply chain; Direct is the sector's own on-site emission.

Definition notes

• NOx. Carried as the flow "Nitrogen dioxide", reported as NO₂; there is no flow named nitrogen oxides.
• PM10. Not a model flow; reported as PM ≤ 2.5 µm plus PM 2.5–10 µm.
• Energy. ENRG is primary energy of extracted resources; for a fuel sector it includes the heat content of the fuel itself. It is not delivered energy, and the older CMU EIO-LCA "Energy" (fuel and electricity consumed along the supply chain) must not be compared with it. NNRG and RNRG split it into nonrenewable and renewable.
• Greenhouse gases and carbon dioxide. GHG is in CO₂ equivalent and includes methane and other gases; for coal it is about five times the carbon dioxide flow alone. Say which one you report.
• Supply-chain share. (N − D) / N for the sector: the fraction of the total that occurs outside the sector you chose. Contributing-sector shares are D_ij L_js / N_is and add to one over all 411 sectors.
• Vintage and region. Inventories of about 2012; imports represented with U.S. production technology; every result is the average for the whole commodity sector.
• Price basis and year. Inputs are converted to 2012 producer prices before intensities are applied; the conversion is shown with the result.

The copied result block

"Copy results + citation" places a tab-separated block on the clipboard: the model version, the sector, your input, the price year and basis, the conversion factors, the demand in 2012 producer dollars, all 23 indicators with supply-chain shares, the air emission flows, the caveats above and a citation line. Values are rounded to six significant figures; the demand is given at full precision so the conversion can be checked by hand. "Download CSV" adds the contributing-sectors table as displayed.

Citing a result

Impacts computed with the CEE 226 EIO-LCA Explorer (USEEIO v2.0.1-411; Ingwersen et al., "USEEIO v2.0, The US Environmentally-Extended Input-Output Model v2.0," Scientific Data 9, 194 (2022); data verified against EPA's published model workbook). Interface: EPA useeio-widgets (open source) with course additions. Sector [code — name]; demand [amount, year, basis]; indicator/flow [the one you report].

Mapping NAICS codes to sectors

sectorcrosswalk.csv maps NAICS codes to the model's BEA commodity codes. Find your NAICS code there, then type the BEA code into the Explorer. Most six-digit NAICS codes map to one sector; some map to a broader sector that combines several.

Data files and verification

• api/USEEIOv2.0.1-411/: sectors, indicators, flows, and the matrices A, L, D, N and N_d, as JSON.
• derived/price_adjusters.json: purchaser-to-producer and price-year factors by sector and year.
• derived/top_flows.json, derived/top_sectors.json, derived/top_sectors_flows.json: per sector, the flows that drive each indicator and the ten largest contributing sectors per indicator and per air flow, computed from the matrices; each records the hashes of its inputs.
• MANIFEST.sha256 lists every file with its hash.

The model files were compared with EPA's published workbook for the same version (largest relative deviation 5 × 10⁻¹⁶), and the tool reproduces a reference set of values within 0.5%.