Lifetime studies of the NO A2S+ (v = 0) Rydberg fluorescence in rare gas matrixes are reported. The fluorescence stems from two types of sites, red and main. The red site fluorescence shows a lifetime lengthening of 25% in Kr matrixes and 100% in Xe matrixes. The main site fluorescence exhibits dramatic lengthenings by orders of magnitude increasing with the host at. polarizability. These results also stress the role of the microscopic structure of the solvent around the mol. on the Rydberg lifetimes. [on SciFinder (R)]