Pollution seems like something that must have always provoked outrage, but in Britain that was not always the case. The famous London smog, etched into history by writers like Dickens and Impressionist painters such as Monet, Turner and Whistler, was once a symbol of prosperity, Dr. Corton said. It signified home fires burning (in Dickens there are grim references to meager fireplaces with just a few lumps of coal) and thrumming factories.