Measurements of the C-H overtone transition strengths combined with estimates of the photodissociation cross sections for these transitions suggest that near-IR photodissociation of peroxy acetyl nitrate (PAN) is less significant (<i>J</i><sub>near-IR</sub>≈3x10<sup>-8</sup>s<sup>-1</sup> at noon) in the lower atmosphere than competing sinks resulting from unimolecular decomposition and ultraviolet photolysis. This is in contrast to the photochemical behavior of a related peroxy nitrate, pernitric acid (PNA), that undergoes rapid near-IR photolysis in the atmosphere with <i>J</i><sub>near-IR</sub>≈10<sup>-5</sup>s<sup>-1</sup> at noon (Roehl et al., 2002). This difference is attributed to the larger binding energy and larger number of vibrational degrees of freedom in PAN, which make 4ν<sub>CH</sub> the lowest overtone excitation with a high photodissociation yield (as opposed to 2ν<sub>OH</sub> in PNA).