Characterization of Non-Methane Total Hydrocarbons (Nmhcs) and Their Ozone Formation Potential for Indoor Cooking Emissions

Non-methane hydrocarbons (NMHCs) are a group of low molecular weight compounds containing only hydrogen and carbon atoms in the C 2 -C 12 range, not only acts as a major precursor for the formation of O 3 through oxidation, but also cause several health problems. Cooking oil fume (COF) is one of the important indoor NMHCs sources. Therefore, this study conducted measurements in a laboratory kitchen to investigate the species and concentrations of NMHC generated during various cooking processes and their impacting factors. The corresponding ozone formation potentials (OFP) were assessed. Results showed the types of oil and seasonings impacts on NMHCs produced during cooking significantly. Alkanes and halogenated hydrocarbons accounted for the largest proportion of NMHCs produced from heating oil. N-dodecane and cyclopentane were the major species for the former one, trichloroethylene, 1,4-dichlorobenzene, toluene, 1,2-dichloroethane and M/p-xylene were for the latter. Heating oil with added seasonings generally released much more NMHCs, but not for heating soybean oil with paprika and pepper, which was mainly because halogenated hydrocarbons decreased significantly, specifically trichloroethylene and 1,2-dichloroethane. The NMHCs concentration per unit mass seasoning was 27483.52-61561.26μg g seasonings -1 h -1 for heating oil with added seasonings. NMHCs released from cooking chili frying meat were 16- 25 times over those produced from cooking tomato frying eggs. Trichloroethylene, toluene, n-dodecane, isoprene, ethylene, and 3-methylpentane were the species with the greatest OFP produced from during cooking. The findings of this study provided scientific evidences for the roles of COF on indoor ozone formation