Method

Factors

• Scope: producing the fuel or electricity plus burning it. Building vehicles and infrastructure is left out.
• Trains: each country's grid mix, not green certificates. Renfe's certificates would give 3.8, the low end of its range.
• Flights: fuel per flight for the aircraft class. With “+ non-CO₂” the CO₂ is multiplied by about 1.7 (1.2–3) for contrails and NOx. Only flights get this.
• Ships: the ship's own fuel per nautical mile from EU reports, split by the ferry share below. Soot and sulphate effects are left out, as in ISO 14083.
• Cars and sailing: logged litres beat any factor (grade A). A yacht's engine hours count 1.2–4 L/h (grade B); add half an hour per hour of dinghy use.
• Occupancy: the factors are at typical loads. An entered head count rescales them.

Ferries

Each sailing split between passengers and freight, three ways. Blue is the passengers' share; every passenger carries an equal slice of it.

By mass instead counts 100 kg per passenger, 1.25 t per car and about 22 t per truck (DESNZ). Per passenger ignores the freight.

Grades

A

Fuel measured for this trip: litres refuelled for a car or logged on a boat.

B

This vessel, service or trip: a ship's own fuel from EU reports, a yacht's engine hours.

C

Operator, model or country: TGV, Renfe, a small petrol car, an aircraft class.

D

Generic for the mode, e.g. "local bus". Worth researching if it matters.

Sources

Every factor and its source: config/emissions.toml. The research behind them: docs/METHODOLOGY.md.