Does Changchun need to be isolated when returning to Yangquan?

No need. When returning to Yangquan from Changchun, there is no need for isolation. Changchun, formerly known as Xi Du and Chachong, is a prefecture-level city, provincial capital, sub-provincial city and I-type big city, and is the core city of Harbin-Changzhou urban agglomeration under the jurisdiction of Jilin Province. It is one of the central cities and important industrial bases in Northeast China approved by the State Council.