An exhaust system for a compression ignition engine comprising: a water adsorbent material; and a catalyst composition for treating an exhaust gas pollutant produced by the compression ignition engine; wherein the water adsorbent material is: (i) arranged to contact exhaust gas from the compression ignition engine before the catalyst composition; and (ii) in thermal communication with the catalyst composition.

An exhaust gas line section, through which an exhaust gas can flow, includes a flow guiding structure, a feed unit configured to supply a liquid additive to the exhaust gas, and a permeable impingement structure, the flow guiding structure, the feed unit, and the permeable impingement structure being positioned one behind the other in the flow direction. The feed unit and the flow guiding structure are arranged and configured such that an impingement region of the liquid additive on the impingement structure overlaps the center of gravity of a flow distribution of the exhaust gas flowing through the impingement structure.

An exhaust system for a compression ignition engine comprising: a water adsorbent material; and a catalyst composition for treating an exhaust gas pollutant produced by the compression ignition engine; wherein the water adsorbent material is: (i) arranged to contact exhaust gas from the compression ignition engine before the catalyst composition; and (ii) in thermal communication with the catalyst composition.