The EMEP/EEA Air Pollutant Emission Inventory Guidebook 2009 is a technical guidance document designed to assist countries in preparing national emission inventories. It provides a comprehensive set of emission estimation methods and emission factors for various sectors, including energy, industrial processes, agriculture, waste, and other sources. The guidebook is structured according to the Nomenclature for Reporting (NFR) and is compatible with the IPCC Guidelines for National Greenhouse Gas Inventories. It aims to ensure that inventories are transparent, consistent, complete, comparable, and accurate (TCCCA criteria). The guidebook is intended for use by parties reporting under the UNECE Convention on Long-range Transboundary Air Pollution and the EU National Emission Ceilings Directive. It also serves as a reference for researchers and can be used for reporting under other international agreements, such as the UN Framework Convention on Climate Change (UNFCCC). The guidebook has been updated to address shortfalls and introduce a tiered approach to determining emissions, with Tier 1 methods being simple and Tier 3 methods being more advanced and data-intensive. The document also includes sections on key category analysis, data collection, time series consistency, uncertainties, inventory management, spatial emissions mapping, and projections.The EMEP/EEA Air Pollutant Emission Inventory Guidebook 2009 is a technical guidance document designed to assist countries in preparing national emission inventories. It provides a comprehensive set of emission estimation methods and emission factors for various sectors, including energy, industrial processes, agriculture, waste, and other sources. The guidebook is structured according to the Nomenclature for Reporting (NFR) and is compatible with the IPCC Guidelines for National Greenhouse Gas Inventories. It aims to ensure that inventories are transparent, consistent, complete, comparable, and accurate (TCCCA criteria). The guidebook is intended for use by parties reporting under the UNECE Convention on Long-range Transboundary Air Pollution and the EU National Emission Ceilings Directive. It also serves as a reference for researchers and can be used for reporting under other international agreements, such as the UN Framework Convention on Climate Change (UNFCCC). The guidebook has been updated to address shortfalls and introduce a tiered approach to determining emissions, with Tier 1 methods being simple and Tier 3 methods being more advanced and data-intensive. The document also includes sections on key category analysis, data collection, time series consistency, uncertainties, inventory management, spatial emissions mapping, and projections.