The rate constants for the CO3-(H2O)n+SO2 reactions were measured for n=0--5 using a variable temperature-selected ion flow tube. Temperature dependences were measured for n=0--3 over the following temperature ranges: n=1, 158--550 K; n=1, 158--270 K; n=2, 158--193 K; n=3, 158--193. The n=4, 5 rate constants were measured exclusively at 158 K. Good agreement is found with previous measurements of the n=0 and 1 rate constants. Expressions are estimated for use in chemical ionization mass spectrometric detection of SO2 in the troposphere.¿ 1997 American Geophysical Union