Column abundances of several atmospheric trace gases have been derived from solar absorption spectra measured from McMurdo, Antarctica, in September and October 1986 and from solar and lunar absorption spectra recorded in Ny Alesund, Spitsbergen, during winter and spring 1992-1995. The results clearly show that denitrification in the Antarctic lower stratosphere results in much smaller column abundances of HNO 3 than in the Arctic. The springtime recovery of HCl in the Antarctic showed a stronger increase than in the Arctic. The ClONO 2 peak occurred about 1 month later in the Antarctic and was found to be less pronounced than in the Arctic. A simple one-dimensional model was able to reproduce the behavior of HCl and ClONO 2 . Results imply that any differences in the O 3 depletion are caused mainly by differences in the stratospheric temperatures and dynamics and only to a small extent by the increased chlorine loading. The total column abundances of the short-lived tropospheric trace gases C 2 H 6 , C 2 H 2 , CO, and CH 2 O are found to be up to 10 times higher in the Arctic compared with the Antarctic.