Development of an Inventory of Public Transportation Emissions: the Case of the Lima-Callao Metropolitan Area

International experience shows that the incorporation of clean fuels has a positive effect that directly affects the emissions of PM, SO2 and other polluting gases, both in new vehicles, and in use. This effect is obtained from the moment it improves the environmental quality of fuels. However, an additional and long-term effect is obtained by introducing vehicles with new technologies, which significantly reduce these pollutants.

Therefore, it is necessary to estimate the benefits of the introduction of cleaner fuels and technologies, for which the development of an inventory of vehicular emissions is one of the tools used. In general, there are two methodologies for the development of inventories of emission, which vary according to the type of base information and the purpose of it:

• Top-down: based on air quality data or on fuel consumption. If a total of emissions is estimated, aggregate and factor data are used for this purpose available for the main emission sources.
• Bottom-up: based on measured or estimated emissions, for this approach the calculation of emissions must be detailed, usually with GIS visualization (type / place of emission). This type of inventory can be used for later quality modeling of the air.

In the present study, an inventory of Bottom-up emissions was developed georeferenced of public transport in Metropolitan Lima. The intention is to estimate in which sectors of the city emit more pollutants and with this, perform different scenarios technologies to visualize changes in polluting emissions. 

It is important to highlight the approval of the Urban Transport Authority for Lima Metropolitana, an autonomous entity that coordinates transport in the provinces of Lima and Callao, and whose main function is "to provide the best service to citizens, within a framework of sustainability economic, environmental and road safety "(Congress of the Republic, Peru, 2018). Therefore, the results of this report could be an important input for this new metropolitan authority.