As mentioned above, both acetone and CO2 can be formed from the thermal decomposition of acetoacetic acid at mild temperatures. Other beta-keto acids can also readily form CO2 upon heating. CO2 elimination can also occur by thermal decomposition of diacyl peroxides, functionalized organic aerosol at mild to moderate temperatures (45-100 °C) leads to the decomposition of oligomers and the formation of CO2, CO, and H2O. In addition, to explain results from thermal desorption instruments, Stark et al. (2017) assumed that heating SOA leads to the loss of carboxyl groups (-CO2), carbonyl groups (-CO), and hydroxyl groups (-H2O, assuming dehydration involving the loss of a hydroxyl group). 18