From global to regional scale: Impact of road traffic emissions

Abstract

Road transport is the most important transport sector for passengers and goods in Europe. According to the European Commission 45.9 % of all goods where transported on roads, while 73.7 % of all passengers where transported by cars in 2010. Due to this large amount of vehicles the road transport sector is an important anthropogenic source of air pollutants. In this study we focus on the emission of nitrogen oxides (NOx), carbon monoxide (CO) and non methane hydro carbons (NMHC), which act as precursors for the formation of ozone in the troposphere. As the chemical system is highly non-linear it is not straight forward to estimate the contribution of the traffic sector to tropospheric ozone. Therefore we are using a detailed Tagging technique to quantify this effect. Our focus is not only on the global, but especially on the regional scale with special attention to the European and German area. Therefore we are using the MECO(n) model system, which couples the regional chemistry climate model COSMO/MESSy on-line to the global chemistry climate model EMAC. This consistent model chain allows us to directly compare effects on the global and the region scale. We will present a detailed evaluation of the chemical system on both scales, including comparisons with ground and airborne based observations. In addition we show results of our Tagging technique, which show that more than 20% of the anthropogenically produced ozone is due to road traffic emissions in Europe (for 2008).