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Annual modulation of $\ensuremath{\gamma}$ rays from $(\ensuremath{\alpha},\ensuremath{\gamma})$ reactions induced by the $\ensuremath{\alpha}$ activity of radon and its daughters was reported by Tiwari, Zhang, Mei, and Cushman (TZMC). While Mohr does not contest the measurements themselves, he has commented that unrealistic $(\ensuremath{\alpha},\ensuremath{\gamma})$ cross sections were used in the analysis of the $\ensuremath{\gamma}$-ray flux, and thus the $\ensuremath{\gamma}$-ray fluxes calculated by TZMC are not reliable. We demonstrate that the $(\ensuremath{\alpha},\ensuremath{\gamma})$ cross sections obtained from talys include the energy-broadened cross sections for discrete states in the high-energy tail of the spectra, which are required in order to compare with the angle-integrated and double-differential spectra obtained from a liquid scintillator detector with an energy resolution of only $\ensuremath{\approx}15%$. A comparison with varying ``elwidth'' shows that cross sections indeed are reliable within the energy region (4 to 10 MeV) reported by TZMC, especially for the dominant contribution, which is the aluminum wall of the detector. Any differences in the $(\ensuremath{\alpha},\ensuremath{\gamma})$ cross sections for $^{16}\mathrm{O}$ at the level detailed by Mohr will have negligible effect on the final flux.

Annual modulation of $\ensuremath{\gamma}$ rays from ($\ensuremath{\alpha},\ensuremath{\gamma}$) reactions in the Soudan Underground Laboratory was observed using a 12-liter scintillation detector. This significant annual modulation, measured over 4 years, can mimic the signature for dark matter and can also generate potential background events for neutrinoless double-$\ensuremath{\beta}$ decay experiments. The measured annual modulation of the event rate from ($\ensuremath{\alpha},\ensuremath{\gamma}$) reactions is strongly correlated with the time-varying radon concentration observed independently in the laboratory. The $\ensuremath{\alpha}$ flux from radon decay is simulated starting from the measured radon concentration, and the $\ensuremath{\gamma}$-ray flux is determined using the convolution of the $\ensuremath{\alpha}$ flux and the cross sections for ($\ensuremath{\alpha},\ensuremath{\gamma}$) reactions. The calculated $\ensuremath{\gamma}$-ray flux is sufficient to generate the measured event rate that exhibits an annual modulation.