Deriving Nitrogen Oxide emissions from inland waterway vessels using MAX-DOAS measurements

Abstract

<p>Inland waterway shipping is an important mode of freight transport in Europe with an extended network especially in Germany, e.g. the Rhine and Danube Rivers, and a variety of artificial channels. Nitrogen oxides (NO<sub>x </sub>= NO + NO<sub>2</sub>), which are also emitted by ships, play an important role in tropospheric chemistry. NO<sub>x</sub> contributes to the formation of tropospheric ozone and thus photochemical smog. Moreover, NO<sub>x</sub> affects human health and increases the acidification of ecosystems.  Monitoring of NO<sub>x</sub> emissions from inland waterway vessels could provide cities that are located along the rivers with valuable information about ship contribution to the pollution.</p><p>In this study, ground-based MAX-DOAS (Multi AXis-Differential Optical Absorption Spectroscopy) measurements were performed along the Rhine River. The aim is to derive NO<sub>2</sub> emissions from individual ships. First sensitivity measurements showed that our Tube MAX-DOAS instrument is sensitive enough to detect a NO<sub>2</sub> signal that can be attributed to passing ships. However, finding the optimal measurement mode to determine the emissions proves to be a challenging endeavour.</p>