Air Travel: Data for the ~Lbs CO2/flight column was obtained by multiplying emissions factors from the GHG Protocol Mobile Combustion Tool and the UK Department for Environment, Food and Rural Affairs (DEFRA) by the approximate corresponding mileage for each type of flight. The number of each type of flight entered is multiplied with ~Lbs CO2/flight to generate Total lbs CO2 for each type of flight. Totals for each type of flight are then summed to produce a total carbon footprint for air travel.

Car Travel: Weighted Avg MPG was obtained from The Bureau of Transportation Statistics.  # miles driven is divided by Weighted AVG MPG to determine Gallons of fuel used.  Gallons of fuel used is multiplied by the emissions factor of 19.6 to convert to lbs CO2.  An emissions factor of 22.4 should be substituted for diesel vehicles. Emissions factors were obtained from the Energy Information Administration, Fuel and Energy Source Codes and Emissions Coefficients.

Electricity: The Weighted Avg $/kWh was obtained from the Energy Information Administration (EIA). The dollar amount entered for the monthly electric bill is divided by this average cost of electricity to determine total kWh Used per month. KWh Used is automatically multiplied by 12 to annualize average monthly electricity usage. This result is then multiplied by the average emissions factor for United States electricity, obtained from http://tonto.eia.doe.gov/FTPROOT/environment/e-supdoc-u.pdf, to generate a total carbon footprint for electricity usage. If clean, renewable power sources that do not result in carbon emissions are used, the total carbon output due to electricity is reduced by the percentage of green power used.

The corresponding total lbs CO2 for each area (air travel, car travel, and electricity) are summed to produce an approximate total carbon footprint estimate.

For non-carbon-related environmental impacts, environmental impact factors have been relatively arbitrarily assigned. The Institute for Lifecycle Environmental Assessment provides costs associated with the large-scale disposal of the above items. We have taken into account these values while attempting to isolate the costs associated with monthly business behaviors, thus resulting in the above environmental impact factors. Based on compositions, we have estimated a cost of $.04 for each can used, $.12 for each PE plastic bottle used, $3 for each cathode-ray tube disposed of, $1 for each hard drive disposed of, and $.80 for each thousand sheets of paper used. Assuming recycling, the approximate monetary cost of the environmental impact associated with standard office furniture is around fifteen percent of its original cost. This amount (fifteen percent of the original value of office furniture) is divided by the total number of years the furniture will be used to yield the furniture's net amortized environmental impact. For simplicity, we have assumed that recycling mitigates seventy percent of the environmental impact of disposal activities. That is, if one-hundred percent of disposal is done through recycling, only thirty percent of the gross environmental impact remains. Individual net impacts are summed to find the total non-carbon-related environmental impact in approximate monetary terms.