The CO$_{2}$, CH$_{4}$, and N$_{2}$O emissions are again adjusted to account for GWP with a result of CO$_{2e }$ (in metric tons). Equation C-13 ( CO$_{2e }$ Emission Calculation for Pacific Northwest Electrical Consumption ) provides an example for electrical consumption in the Pacific Northwest. 

CO$_{2 }$(metric tons) = Electrical Consumption (kWh) x 819.21 pounds CO$_{2 }$per MWh x short ton per 2,000 pound x 0.907185 metric ton per short ton x 0.001 MWh per kWh 

CH$_{4 }$(metric tons) = Electrical Consumption (kWh) x 15.29 pounds CH$_{4 }$per GWh x short ton per 2,000 pound x 0.907185 metric ton per short ton x 0.000001 GWh per kWh 

N$_{2}$O (metric tons) = Electrical Consumption (kWh) x 12.50 pounds N$_{2}$O per GWh x short ton per 2,000 pound x 0.907185 metric ton per short ton x 0.000001 GWh per kWh 

CO$_{2e }$(in metric tons) = Electrical CO$_{2 }$+ Electrical CH$_{4 }$x 34 + Electrical N$_{2}$O x 298 

## Equation C-13. CO$_{2e }$Emission Calculation for Pacific Northwest Electrical Consumption 

## C.2.7 Waste Management 

Most airports have implemented waste management activities designed to recycle various forms of waste. These activities produce GHG emission reductions when contrasted with activities that do not recycle (i.e., divert waste from landfills). 

GHG emissions related to the waste management practices should be estimated using EPA’s Waste Reduction Model (WARM) 68 . WARM is available both as a Web-based calculator and as a Microsoft Excel spreadsheet. WARM calculates and totals GHG emissions of baseline alternative waste management practices—source reduction, recycling, combustion, composting, and landfilling. The model calculates emissions in metric tons of CO$_{2e }$ for 26 materials and 8 mixed material categories (e.g., construction and demolition waste, aluminum cans, glass, plastic, paper, wood, and metals , etc.) commonly found in municipal solid waste (MSW). The emission factors represent the GHG emissions associated with managing one short ton of MSW in a specified manner. 

WARM also provides several options for landfill emissions modeling, including whether or not landfill gases are recovered. Emissions from the transportation of the waste to the landfill are also incorporated into WARM. Default transportation distances of 20 miles can be used if site- specific data is unavailable. 

For each material type, the amount of material recycled, landfilled, composted, and/or combusted is input into WARM. GHG savings are then be calculated by comparing the emissions associated with the alternative scenario with the emissions associated with the baseline scenario. 

## C.2.8 Refrigerant Usage 

The following section discusses the methodologies for computing GHG emissions refrigerant usage at airports. At airports, refrigeration usage can be composed of air conditioning and heat pumps, chillers, fire extinguishers, and storage refrigeration. 

