Documentation

• Indicators and units
• Air emission flows
• Definition notes
• What the results page shows
• The copied result block
• Citing a result
• Mapping NAICS codes to sectors
• Data files and verification

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

Definition notes

• NOx. The model carries nitrogen oxides as the flow "Nitrogen dioxide", reported as NO₂. There is no flow named nitrogen oxides.
• PM10. Not a model flow. The tool reports it as PM ≤ 2.5 µm plus PM 2.5–10 µm.
• Energy. The ENRG indicator is primary energy of extracted resources. For a fuel sector it includes the heat content of the fuel itself. It is not delivered energy. The older CMU EIO-LCA models report "Energy" as fuel and electricity consumed along the supply chain, so the two quantities must not be compared. 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 mining it is about five times the carbon dioxide flow alone. Say which one you report.
• Vintage. Emissions reflect about 2012 U.S. inventories. Differences from 2002-era results are partly real emission-control progress and partly definition.
• Single region. Imported inputs are represented with U.S. production technology.
• Sector averages. 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.

What the results page shows

• Total. The indicator for your dollars, including the whole supply chain.
• Supply-chain share. The fraction of the total that occurs outside the chosen sector: (N − D) / N for that sector.
• Drivers. The flows that make up the indicator for that sector, with each flow's share.
• Contributing sectors. The ten sectors, anywhere in the supply chain, in whose production the largest parts of the total occur, with values and shares. The sector itself is usually first. Shares are computed as D_ij L_js / N_is and add to one over all 411 sectors.

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 adjusters applied, the effective demand in 2012 producer dollars, all 23 indicators with supply-chain shares, the air emission flows with totals and direct values, the caveats above, and a citation line. The block is the same whatever category is displayed. Values are rounded to six significant figures; the effective demand is given at full precision so the price conversion can be checked by hand.

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

The file sectorcrosswalk.csv maps NAICS codes to the model's BEA commodity codes. Search it for your NAICS code, then search the tool for the BEA code. 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: Φ and ρ by sector and year, from the model's price tables.
• derived/top_flows.json: per sector, the flows that drive each indicator, and the air emission flows with total and direct values.
• derived/top_sectors.json: per sector and indicator, the ten largest contributing sectors and their shares, computed from D and L. The file records the hashes of the matrices it was built from.
• MANIFEST.sha256 lists every file with its hash; verify_deploy.sh checks a deployed copy against it.

The model files were compared with EPA's published workbook for the same version; the largest relative deviation was 5 × 10⁻¹⁶. The tool's own check reproduces a reference set of coal values within 0.5%.