Work out your bus emissions

= 3.33 tonnes CO2e in 2026 (Scope 3)

Each passenger-mile × 0.06664 kg CO2e, the 2026 GHG Emission Factors Hub figure (Cornerstone) for "Bus", CO2, CH4 and N2O combined.

That is one line of your footprint. Want the whole thing done for you?

Carbon Recycling holds every UK government factor for every year, works out each line from your bills, mileage and travel, and writes your Carbon Reduction Plan and SECR report.

Start your 14-day free trialTry our free tools

No card needed for the trial.

Bus: emission factor by Hub edition (per passenger-mile)

From Table 10, Scope 3 Category 6 and 7: Business Travel and Employee Commuting, row "Bus". The Hub publishes the three gases separately; the kg CO2e column adds them up with the global warming potentials (GWPs) each edition states.

Editionkg CO2g CH4g N2OGWPs (CH4, N2O)kg CO2e per passenger-mileChange
2026 (Cornerstone)0.066000.0046000.00190027, 2730.06664+0.02%
2025 (EPA)0.066000.0046000.00190028, 2650.06663-6.7%
2024 (EPA)0.070710.0050300.00212628, 2650.07141+28.7%
2023 (EPA)0.055000.0063000.00110025, 2980.05549–

The gases changed between editions as the Hub updated its source data, and the GWPs changed too (2023: CH4 25, N2O 298 (IPCC AR4); 2024: CH4 28, N2O 265 (IPCC AR5); 2025: CH4 28, N2O 265 (IPCC AR5); 2026: CH4 27, N2O 273 (IPCC AR6, non-fossil CH4)). Source: US EPA, GHG Emission Factors Hub (2023-2025 editions, public domain) and Emission Factors Hub 2026, Cornerstone Sustainability Data Initiative, CC BY 4.0.

Worked example

Take a workforce whose commuting survey adds up to 50,000 passenger-miles a year. 50,000 passenger-miles × 0.06664 kg CO2e = 3.3 tonnes CO2e, reported as Scope 3, Category 7 (employee commuting) or 6 (business travel). In metric units the factor is 0.04141 kg CO2e per passenger-km (one mile is exactly 1.609344 km).

How to use it

Multiply the passenger-miles for each trip by the factor for that mode and report the total as Scope 3, Category 7 (employee commuting) or 6 (business travel). Under the GHG Protocol's Scope 3 Standard, business travel is Category 6 and employee commuting Category 7.

The Hub gives one bus figure per passenger-mile, from national passenger-mile data, so it is one average for all buses. Use it for city buses and intercity coaches unless your operator publishes its own figure.

Check the unit. These figures are per passenger-mile, so multiply by the miles each traveller covers, not the miles the vehicle covers. Booking tools outside the US often report kilometres; divide by 1.609344 to get miles before using these figures.

UK companies with sites, staff or shipments in the US can use these figures for that activity, and the UK government factors for activity in the UK (see the UK government factor for the same activity). Say in your methodology which set you used for which activity. In Carbon Recycling, every line keeps the factor and source it was worked out with.

Where to find your passenger-mile figure

An employee commuting survey, or tickets and expense claims for business trips.

Who publishes the 2026 figures

The GHG Emission Factors Hub was published by the US EPA's Center for Corporate Climate Leadership every year up to the January 2025 edition, as a US government work in the public domain. The 2026 edition, last updated 26 May 2026, was published by the Cornerstone Sustainability Data Initiative, not by EPA, under a CC BY 4.0 licence (doi:10.5281/zenodo.20403776). It keeps EPA's table layout and its footnotes cite the same sources, such as 40 CFR Part 98 and EPA's Inventory of US Greenhouse Gas Emissions and Sinks. EPA has not endorsed it.

Related emission factors