Q800. What factors could have influenced greenhouse gas trends?

A800. In general, observed trends in greenhouse gas totals presented in GHGRP data are due to changes in data reported by facilities. The annual variation in reported emissions generally is influenced by opening and closing of plants and processes, alterations or enhancements to manufacturing processes, and variations in annual production volume due to customer demand. However, for some industry sectors, EPA over time has adopted revisions to emission calculation methods for some sectors to reduce burden on reporters, simplify emission calculations, or improve the quality of the reported data. In some cases, these changes in calculation methods can impact observed trends.