inventory results  methodology  downloads  participants  acknowledgements		The YCI study addressed emissions from four categories of sources: power plants, buildings, transportation, and "other". The following briefly decribes the selection of a study boundary, scope of the inventory, collection of data, emissions calculations, and estimation of uncertainty. For more detailed information on the methodology and results, the full report will be available for download soon. Study Boundary The organizational boundary established for the YCI study encompassed all activities related to the educational mission of the University. The operational boundary of the study included all direct and indirect emissions of the six GHGs. Direct emissions are those emissions from sources that Yale University owns or controls, while indirect emissions are the emissions as consequences of Yale's activities but not necessarily owned or controlled by Yale. This study was conducted for the calendar year 2002 (note is made where only fiscal year data were available). Study Scope The study was broken up into tiers. Six tiers were identified: Tier 1, Yale emissions from Yale power plants; Tier 2, Yale emissions from activities for which Yale has the decision-making power, either through procurement process or an equivalent; Tier 3, Yale emissions from Yale activities that are decided and transacted by other individuals; Tier 4, Yale's emissions from its outsourced activities where decisions are made through contract provisions; Tier 5, Yale's incidental emissions; and Tier 6, Yale's emissions from embodied energy. The study was limited to the first four tiers based on available data. Data Collection All relevant activity data were gathered from institutional sources and University suppliers and the emissions from the sources calculated based on a four working group organization structure delineated by Power Plants, Buildings, Transportation (including fleet, work-related, and commuter travel) and Other Sources (including solid waste, laboratory chemicals and refrigerants, as well as sinks). Emissions Calculations Emissions factors are source-specific and convert activity data into emissions values. The relevant emissions factors for specific fuels were found in order to calculate emissions. Published emissions factors were researched and collected from leading sources, such as IPCC, EPA, and others. Once activity data and emissions factors for a specific source were identified, GHG emissions in Tons CO2 equivalent were calculated. Uncertainty Uncertainties were calculated for the data and conversion factors were based on specific uncertainties from different sources of data errors, human errors, and other errors due to assumptions made when collecting and analyzing the data.