PM _2.5 and ultrafine particles emitted during heating of commercial cooking oils

Seven commercial cooking oils were investigated to determine the PM _2.5 mass and ultrafine particle (UFP) emission rates and emission fluxes (rates per area). The results of this study showed that at 197°C soybean, safflower, canola, and peanut oils produced lower PM _2.5 emission fluxes (6.1×10 ⁵, 3.0×10 ⁵, 5.4×10 ⁵, and 3.9×10 ⁵μg/min/m ², respectively) than corn, coconut, and olive oils (2.7×10 ⁶, 2.9×10 ⁶, and 5.7×10 ⁶μg/min/m ², respectively). Similarly, the total particle number flux at 197°C was lower for soybean, safflower, and canola oils (3.5×10 ¹³, 8.6×10 ¹³, and 1.0×10 ¹⁴#/min/m ², respectively) than the corn, coconut, olive, and peanut oils (2.4×10 ¹⁴, 1.4×10 ¹⁴, 1.7×10 ¹⁴, and 3.8×10 ¹⁴#/min/m ², respectively). In general, oils with a higher smoke temperature resulted in lower particle concentrations over the measured temperature range (131-197°C). The percentage of UFP (particle diameter D _p 10-100nm) to total particles (D _p 10-500nm) ranged from 76 to 99% for this temperature range. Particles below 10nm in diameter were not measured. The particle number size distribution showed a polydisperse behavior with major mode sizes ranging from 25nm (for peanut oil) to 82nm (for soybean oil) at an oil temperature of 197°C. Practical Implications: The study presents particle number and mass concentrations, size distributions, emission rates, and emission fluxes from heating common cooking oils. The emission rates and emission fluxes can be used as inputs to models for indirect exposure analysis studies. The study may also be used to provide guidance on choosing oils that result in lower emission rates when heated.