<p>Identification of atmospheric molecular clusters and measurement of their concentrations by APi-TOF mass spectrometers may be affected by systematic error due to possible decomposition of clusters inside the instrument. Here, we perform numerical simulations of decomposition in an APi-TOF and formation in the atmosphere of a set of clusters which involve a representative kind of highly-oxygenated organic molecule (HOM), with molecular formula C<sub>10</sub>H<sub>16</sub>O<sub>8</sub>. This elemental composition corresponds to one of the most common mass peaks observed in experiments on ozone-initiated autoxidation of <i>α</i>-pinene. Our results show that decomposition is highly unlikely for the considered clusters, provided their bonding energy is large enough to allow formation in the atmosphere in the first place.</p>