Calculate total CO2 exposure per mode and scenario
Source:R/scenario_co2_calculations.R
      scenario_co2_calculations.RdCalculate total CO2 exposure for each mode and for each scenario based on the CO2 emissions inventory
Details
This function performs the following steps:
- calculate emission factors for each mode by dividing total emissions by distances travelled 
- calculate CO2 emissions for each mode in each scenario by multiplying the scenario distance times the emission factors 
- for modes without any assigned distance, use the CO2 emissions from the VEHICLE_INVENTORY instead