I just turned in a story called "Fire's Children" for ELEMENTAL MAGIC, an anthology set in Mercedes Lackey's Elemental Masters world, scheduled to be published by DAW Books on December 4, 2012. The elements are earth, air, fire, and water.
My story is set more or less in the London that my great-grandfather emigrated from. He must have been pretty tough; he spent 25 years in East London (yes, he was a Cockney), and he lived to be 87, which is 17 years more than the Biblical "three score and ten." His father (born 1834) and grandfather (born 1805) both lived less than 36 years, or about half of that. Their London could have used elemental mages, and considering the condition of some of those elements gave me ideas for my story.
London in the 1800s was not a healthy place to live. In modern-day New York City you can see the air (and breathing it is said to be the equivalent of smoking a pack of cigarettes a day). In a London heated by burning coal, you could not only see the air, you could almost chew it. And when water vapor was added to it--well, London fogs were notorious for good reasons. Then there was the water. My annual Water Quality Report just arrived in the mail. The report on things they test for runs a full letter-size page of fairly small print, with a key to the abbreviations taking up a third of the next page. There are standards for color and for turbidity (contamination comes from "naturally occurring organic materials" and "soil runoff") and a lot of other things, and there's no way any large city that used horses as primary transportation would ever meet these standards. Some people may complain about tap water, but it doesn't give you dysentery or cholera.
There's a saying that those who don't remember history are condemned to repeat it. What I like about history is that I can see that--at least in some areas--we've made progress.