Chlorine levels are down 11.5% since they peaked in 1993, and bromine is at lower levels in the air, dropping 14.5 percent since its 1999 peak, the report said.

报告表示，其中氯的大气含量相比 1993 年的峰值下降了 11.5%，溴在大气中的水平比较低，含量较 1999 年的峰值下降了 14.5%。