Air conditioning eventually reach the upper atmosphere. Once the refrigerant reaches the stratosphere, UV radiation from the Sun homolytically cleaves the chlorine-carbon bond, yielding a chlorine radical. These chlorine radicals catalyze the breakdown of ozone into diatomic oxygen, depleting the ozone layer that shields the Earth's surface from strong UV radiation. Each chlorine radical remains active as a catalyst until it binds with another radical, forming a stable molecule and quenching the chain reaction. Prior to 1994, most automotive air conditioning systems used R-12 as a refrigerant. It was replaced with R-134a refrigerant, which has no ozone depletion potential. Old R-12 systems
Burning Like the Midnight Sun the Midnight Sun" has received some of the most positive reviews of any album in the band's career. Jeff Eibel, writing for the Spin Control column in the "Chicago Sun-Times", called The Choir's latest release "a late-career triumph," and remarked that "Midnight Sun" was the band's "second exceptional album in a row, and its best since 1990's landmark "Circle Slide"." "Christianity Today"′s Andrew Greer highlighted the band's ability to create "smooth musical clarity to contrast the murky exploration of everyday faith," while "The Phantom Tollbooth"′s Derek Walker called "Midnight Sun" a "sonic delight" and The Choir's "most cohesive, melodic and