The emission of volatile species accompanying the fracture of polystyrene has been monitored as a function of time by two quadrupole mass spectrometers mounted at different distances from the sample. The resulting time-of-arrival signals were numerically modeled to yield an estimate of the energy per unit area dissipated as heat by fracture. Neutral emissions of ethyl benzene molecules (a common volatile impurity) and a noble gas (Ar-introduced by exposure) were monitored. Dissipation (fracture) energies determined ranged from 680 to 1480 J/cm2, consistent with the range of energy release rates in the literature. The peak surface temperatures calculated from the measured heat dissipation ranged from 600 to 1300 K.