Different high-level quantum chemical composite methods such as the Gaussian-n and Weizmann-n theories have been used to derive enthalpy of formation values from calculated atomization energies and scheme isodesmic reactions of peroxide pollutants. The resulting values of ΔH°f298K de HOOH, HOOF, HOOCl, HOONO, FOOF, FOOCl, FOONO, ClOOCl y ClOONO son -32,2 ± 0,8; -10,9 ± 1,1; -8,4x10 - 2 ± 1,2; -2,9 ± 0,7; 8,4±1,6; 21,5±1,3; 19,7±1,3; 32,3 ± 1,4 and -31,3 ± 0,8 kcal mol-11, respectively. A comparison with previous experimental and theoretical values are presented highlighting the high chemical accuracy with low computational cost. [ABSTRACT FROM AUTHOR]