Abstract. Cooking emissions account for a major fraction of urban
organic aerosol. It is therefore important to understand the atmospheric
evolution in the physical and chemical properties of organic compounds
emitted from cooking activities. In this work, we investigate the formation
of secondary organic aerosol (SOA) from oxidation of gas-phase organic
compounds from heated cooking oil. The chemical composition of cooking SOA
is analyzed using thermal desorption–gas chromatography–mass spectrometry (TD–GC–MS). While the particle-phase composition of SOA is a highly complex
mixture, we adopt a new method to achieve molecular speciation of the SOA.
All the GC-elutable material is classified by the constituent functional
groups, allowing us to provide a molecular description of its chemical
evolution upon oxidative aging. Our results demonstrate an increase in
average oxidation state (from −0.6 to −0.24) and decrease in average carbon
number (from 5.2 to 4.9) with increasing photochemical aging of cooking oil,
suggesting that fragmentation reactions are key processes in the oxidative
aging of cooking emissions within 2 d equivalent of ambient oxidant
exposure. Moreover, we estimate that aldehyde precursors from cooking
emissions account for a majority of the SOA formation and oxidation
products. Overall, our results provide insights into the atmospheric
evolution of cooking SOA, a majority of which is derived from gas-phase
oxidation of aldehydes.
Primordial atmospheric evolution recorded in the Martian mantle
