At present, control of spontaneous combustion in goafs of coal mines mainly depends upon the injection of liquid or gas (inert) media. In this work, we attempted to use ultrasonic waves to produce a novel phase-transition aerosol. After treatment, gel layers were produced on the coal surface, whose formation is attributed to the reaction between aerosol particles of acrylamide and H3BO3. Additional experiments were performed to compare the effects of aerosol produced using MgCl2, CaCl2, and KH2PO4. Results show that the net weight of 10 g coal samples increased by 1.336 g after being treated with the phase transition aerosol for 120 min. Thermogravimetry/differential scanning calorimetry tests indicated that the heat released from the treated coal samples was significantly inhibited and the activation energy of low-temperature oxidation at 50-150 degrees C also increased significantly. According to in situ infrared spectral studies, the phase-transition aerosol inhibited the activation of the -CH2- structure in coal. Importantly, the oxygen uptake of phase-transition-aerosol-treated coal declined by 34.1% following treatment. This result indicates that the phase-transition aerosol effectively prevented the contact between oxygen and coal and chemically inhibited the activation of groups during the low-temperature oxidation of coal.