In Chapter 17 of Harper Lee's To Kill a Mockingbird, Scout recalls last Christmas being near the Ewells' house close to the county dump and the "Negro settlement." Each year after Christmas, the Finch family is in that part of the county because the mayor of Maycomb has asked his citizens to "help the garbage collector by dumping [their] own trees and trash."
In her narrative, Scout specifically details remembering turning the car around in the front yards of the Negroes' cabins, which gave her a chance to observe the settlement. She describes their cabins as looking "neat and snug" and notes the smoke rising from their chimneys. But what affects Scout and Jem, as well as Atticus, the most are the "delicious smells" in the air, such as chicken, bacon, and squirrel. Atticus himself is able to identify the smells of possum and rabbit cooking, smells that Atticus is well familiar with as an "old countryman" and that have a longstanding history in Maycomb's Negro community. Scout further notes that all the wonderful aromas of the Negro settlement disappeared as they drove past Ewell's house.
Scout has these recollections just as Bob Ewell is taking the witness stand. Her recollections help place Ewell in his social class and characterize his level of humanity. Economically speaking, he is in the same social class as the Negroes. Yet, the aromas that surround the Negro settlement help classify the Negroes as being far more human and cultured than Ewell. Though the Negroes may be poor, they have enough sense to take what they can from the land and feed themselves well. Ewell doesn't have this same sense; his life revolves around drinking booze, doing what labors he must do, and abusing others. And, as Scout notes, his lack of humanity is reflected in the lack of aromas surrounding his home.