What crucial element, when multiplied by the type of fuel used, determines the true long-term environmental impact of rocketry?

Answer

The multiplication factor of launch frequency

The multiplication factor of frequency is a crucial element; even a vehicle using a 'cleaner' fuel becomes environmentally suspect if launches occur at a very high frequency, depositing substantial byproducts repeatedly into sensitive atmospheric layers.

What crucial element, when multiplied by the type of fuel used, determines the true long-term environmental impact of rocketry?
propulsionrocket fuelcombustionemissions