Dirty cities in the dirty south

So I was reading over the list of Travel+Leasure's America's Favorite Cities and noticed that a lot of the cities had something in common other than their size.  About half of the top 10 cities are located in the south.  I wonder if the magazine's readers have something against the south or if they just think big cities are dirty.  New Orleans came in as the 2nd dirtiest city in America and Atlanta Georgia ranked 5th despite a smoking ban recently inacted to keep cigarrette butts out of parks in the city.  Brendan Spaar thinks that keeping a city the size of a top 10 market clean is nearly impossible.  With that many people roaming around at all hours of the day and night, you're fighting a losing battle.  Click the source link to see the full list (spoiler alert: nearly the entire top 10 are the top 10 by population size)

Source:  http://travel.yahoo.com/ideas/america%E2%80%99s-dirtiest-cities.html