Measurement of Emissions from Air Pollution Sources. 4. C1−C27Organic Compounds from Cooking with Seed Oils

Abstract

The emission rates of gas-phase, semivolatile, and particle-phase organic compounds ranging in carbon number from C1 to C27 were measured from institutional-scale food cooking operations that employ seed oils. Two cooking methods and three types of seed oils were examined: vegetables stir-fried in soybean oil, vegetables stir-fried in canola oil, and potatoes deep fried in hydrogenated soybean oil. The emission rates of 99 organic compounds were quantified, and these include n-alkanes, branched alkanes, alkenes, n-alkanoic acids, n-alkenoic acids, carbonyls, aromatics, polycyclic aromatic hydrocarbons (PAH), and lactones. Carbonyls and fatty acids (n-alkanoic and n-alkenoic acids) make up a significant portion of the organic compounds emitted from all three seed oil cooking procedures. The compositional differences in the organic compound emissions between the different cooking operations are consistent with the differences in the organic composition of the various cooking oils used. The distribution of the n-alkanoic acids between the gas and particle phases was found to be in good agreement with gas/particle partitioning theory. The relative importance of emissions from commercial deep frying operations to the total emissions of C16 and C18 n-alkanoic acids in the Los Angeles urban area was estimated using the available information and is estimated to account for approximately 7% of the total primary emissions of these acids. Additional emissions of these n-alkanoic acids from stir-frying and grill frying operations are expected. Estimates also indicate that seed oil cooking may make up a significant fraction of the emissions of lighter n-alkanoic acids such as nonanoic acid.