Volkswagen have been in the news for all the wrong reasons over the past week. The company admitted to installing a ‘defeat device’ in millions of cars which made it appear in emissions tests that they emitted far lower levels of particular pollutants than they actually did in normal road conditions. Plenty of articles have looked at the particulars of the scandal since the story broke last week, so as well as considering the pollutants involved in the VW story, here we’ll also take a closer look at how we use chemistry to remove pollutants from vehicle emissions.