Refining the Resolution of Domestic Combustion Sector Emissions in Barcelona

Green infrastructures are being promoted in cities to improve air quality and thermal comfort of urban dwellers, among other ecological, economic and social benefits, but there is still little quantitative evidence of how efficient they are in achieving the aforementioned sense. We aim to fill this research gap, by employing state of the art methodologies and the numerical chemical-weather modelling system (WRF-Chem) which requires spatially and temporally resolved emissions of atmospheric pollutants from anthropogenic and biogenic sources. Presently, emission inventories are available up to 1 km²resolution (HERMESv2 - BSC) over the Metropolitan Area of Barcelona (MAB). However, we need more resolved emissions to quantify the effect of green infrastructures which could be relatively small areas such as green roofs and parks. Recently, the Cartographic and Geological Institute of Catalonia (ICGC), jointly with the University of Barcelona, developed the Local Climate Zones (LCZ) map of the MAB. The main advantage of using LCZ instead a common land use database is that LCZ provide better spatial discretization of urban and sub-urban land uses. We use the LCZ map of the MAB to disaggregate domestic combustion emissions from 1km to 100m grid-size having LCZ land use classes and population density as the main proxy (other proxies like population density are also considered). The use of LCZ at such higher resolution provides a better reallocation of emissions to residential areas instead of over other land use not related to domestic combustion activity. The more discretized emission product is used as input data for WRF-chem simulations using urban canopy schemes at high horizontal resolution. We also discuss other methods for the rest of the emissions sectors, such as traffic, biogenic (from green areas and urban/per-urban agriculture), etc.