Comment on acp-2022-320

Abstract

To elucidate the molecular chemical compositions, volatility-polarity distributions, as well as influencing factors of Chinese cooking emissions, a comprehensive cooking emission experiment was conducted. Semi-volatile and intermediate volatility organic compounds (S/IVOCs) from cooking fumes were analyzed by a thermal desorption comprehensive two-dimensional gas chromatography coupled with quadrupole mass spectrometer (TD-GC×GC-qMS). Emissions from four typical Chinese dishes, i.e., fried chicken, Kung Pao chicken, pan-fried tofu, and stir-fried cabbage were investigated to illustrate the impact of cooking style and material. Fumes of chicken fried with corn, peanut, soybean, and sunflower oils were investigated to demonstrate the influence of cooking oil. A total of 201 chemicals were quantified. Dishes cooked by stir-frying or deep-frying cooking styles emit much more pollutants than relatively mild cooking methods. Aromatics and oxygenated compounds were extensively detected among meat-related cooking fumes, while a vegetable-related profile was observed in the emissions of stir-fried cabbage. The volatility-polarity distributions of the four dish emissions were quite similar, yet the distributions diverged when different types of oils were utilized. Ozone formation potential (OFP) was dominated by chemicals in the VOC range. 10.2 % - 32.0 % of the SOA estimation could be explained by S/IVOCs. Pixel-based partial least squares-discriminant analysis (PLS-DA) and multiway principal component analysis (MPCA) were utilized for sample classification and key components identification. The results indicated that the oil factor explained more variance of chemical compositions than the cooking style factor. MPCA results emphasize the importance of the unsaturated fatty acid-alkadienal-volatile products mechanism (oil autooxidation) accelerated by the cooking and heating procedure.