A small emitter is a non-commercial air transport operator (i) whose flights in aggregate emit less than 10 000 tonnes of CO2 per annum; or (ii) which operates fewer than 243 flights per period for 3 consecutive 4-month periods. A small emitter can take advantage of a simplified procedure to monitor its emissions of CO2 from its flight activity. This procedure is described in Section 4 of Annex XIV of the Monitoring Decision and involves the use of a calculation tool developed by EUROCONTROL or similar tool developed by other organisations.