Road transport emissions in EDGAR (Emissions Database for Global Atmospheric Research)

Road transport on one hand plays an important role in the world economy and significantly contributes to the global gross domestic product; on the other hand, it is one of the main sources of air pollution and greenhouse gas emissions, mostly originating from the consumption of liquid fossil fuels. One of the main tools to monitor emissions, in an effort to reduce them, is to maintain inventories where emissions are estimated on a regular basis. Many countries maintain their own inventories, while there are also centralised databases gathering data from various countries and producing aggregated results, e.g. on total European Union level. However, maintaining emission inventories on a global scale is a tedious process mainly due to lack or poor quality of data for some countries and because of inconsistencies in the emission estimation methodologies followed. This article presents the methodology and results of a global road transport emission inventory, as part of the EDGAR (Emissions Database for Global Atmospheric Research) v6.1 database. It covers the majority of countries and regions in the world, i.e. global road vehicle fleet emissions. The vehicle emission processes considered comprise exhaust, fuel evaporation, tyre and brake wear, and road abrasion. The methodology involves the collection and processing of the relevant statistical data, i.e. vehicle fleet, activity, and energy from various sources. This information is combined with the appropriate emission factors, resulting in emission calculations per country, year, and vehicle category. The dataset developed is validated by comparison against official inventories and third-party emission estimates. The current database can be used to obtain a global view of emissions from the road transport sector for the period 1990–2020. Significant conclusions can be reached from analysing this dataset, for example which countries contribute the most to each pollutant, which vehicle types are the biggest emitters and more. The dataset can be useful for emission and air quality modellers, scientists and policy makers and can help design better policies for the future.