6. Business travel

Select one of the buttons below to enter your scope 3 category 6 data. There are two options: Business travel & study abroad (distance traveled), and Purchasing data (dollars or MT eCO2).

Business Travel & Study Abroad (distance traveled)  Air travel paid for by the institution is required for Second Nature signatories

Purchasing Data (USD)

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What is business travel? 

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The business travel category includes emissions from transportation of employees for activities related to the organization. This only includes travel that does not take place in vehicles owned by the organization; travel in vehicles owned by the organization should be reported in scope 1. Examples include air travel, personal mileage reimbursement, and travel by train. Business travel is category 6 of scope 3.

Air travel and radiative forcing

Radiative forcing is associated with emissions at higher altitudes and results in a higher global warming effect. Air travel CO2 emissions are multiplied by the radiative forcing factor to account for the higher global warming potential from emissions released at higher altitudes. The radiative forcing factor is also sometimes referred to as the radiative forcing index.

SIMAP accounts for radiative forcing for all air travel CO2 emissions. Radiative forcing does not apply for CH4 and N2O emissions. To calculate your total air travel emissions, SIMAP multiplies the radiative forcing factor by the air travel emissions factor (see the emissions factors page). The SIMAP calculation is as follows:

        Passenger miles * air travel CO2 emissions factor * radiative forcing factor

SIMAP has two options for the air travel radiative forcing factor: 2.7 (default, IPCC) and 1.9 (DEFRA). See the SIMAP guidance on air travel emissions for more information about radiative forcing.

What options are available in SIMAP for business travel data entry?

There are 2 data entry categories for business travel in SIMAP: Business travel & study abroad and Purchasing data.

  • Business travel & study abroad: Enter activity data specific to the mode of transport. The specific options in SIMAP are: 
    • Directly financed air travel. Units: Passenger miles or US dollars.
    • Ground travel: Charter buses. The types of buses in SIMAP are diesel, CNG, alternative fuel, and other. Units: vehicle miles.
    • Ground travel: Personal mileage reimbursement. Units: Vehicle miles.
    • Ground travel: Public bus. Units: Passenger miles.
    • Ground travel: Train. Units: Passenger miles.
    • Ground travel: Taxi / ferry / rental car. Units: Vehicle miles.
    • Other: This source has no default emission factors and is intended to be customized.
    • Study abroad air travel. Units: Passenger miles or US dollars.
  • Purchasing data: Enter dollars spent on purchasing categories. You can assign any of the purchasing data categories to the business travel category. Note that purchasing data is intended to provide an order of magnitude estimate; enter more detailed activity data (e.g., weight of food) whenever possible. See this page for guidance on purchasing data entry.


GHG Protocol Corporate Value Chain (Scope 3) Accounting and Reporting Standard