Air conditioning
Modern air conditioning emerged from advances in chemistry during the 19th century, and the first large-scale electrical air conditioning was invented and used in 1902 by US inventor Willis Carrier. The introduction of residential air conditioning in the 1920s helped enable the great migration to the Sun Belt in the United States.
Ice cube
American physician and humanitarian John Gorrie built a refrigerator in 1844 with the purpose of producing ice to cool air. His refrigerator produced ice which he hung from the ceiling in a basin to lower the ambient room temperature. During his time, bad air quality was thought to cause disease. Therefore, in order to help prevent and treat sickness, he pushed for the draining of swamps and the cooling of sickrooms.