The mass-production of cotton resulted in America gaining funds from selling goods (cotton, other things relating to cotton), therefore creating more factories, towns, and other sources of income.
The large amount of factories also caused overpopulation in many cites, due to the fact that more jobs were available in areas with more of those said factories.
This caused the unsanitary nature of many big cities, and possibly homelessness.
Overall, the cotton gin affected multiple aspects of America physically and socially with the pollution of the air, overpopulation, slavery, and the American economy.
Ira Berlin: Generations of Captivity: A History of African-American Slaves, Cambridge, London: The Belknap Press of Harvard University Press, 2003 (second graph/chart)