The Valley of Ashes, the dumping ground of the industrial production of New York City, is a wasteland where everything is an ominous and disintegrating grey--hills of ash, "grotesque gardens," train cars, the foul river, ashen men with leaden spades, who raise a bleak cloud of ashes.
In contrast to this ash-heap of land and murky water and nebular air and sky is the home of Daisy and Tom Buchanan is described as "a cheerful read and white Georgian Colonial mansion." The green lawn spans a fourth of a mile; French doors that "reflected gold" are wide open to allow the warm windy afternoon breeze to come inside the "bright rosy-colored space" and ripple the curtains as though they were flags, casting shadows upon the wine-colored rug. Unlike the stagnant atmosphere of the Valley of Ashes, everything in the large room that Nick enters seems to flow as sunlight "ripples," blowiing shadows upon things "as wind does on the sea." Nick comments that the only stationary object is the enormous couch on which two young women are "buoyed up as though upon an anchored balloon." Even their dresses flutter as though they have just landed after a "short flight around the house." Fascinated by the illusion of movement, Tom listens to the "whip and snap of the curtains" as though they were the sails on a yacht.
Clearly, the Buchanan house connotes movement, cleanliness, and freshness in contrast to the stagnation, decay, and greyness of The Valley of Ashes that symbolizes the decadence and waste of the Jazz Age, a period that dissembles as a celebratory time, a time of freedom and prosperity, all the time hiding its underlying corruption.