Fine and Ultrafine Particle Emissions from Electric Burners and Stainless Steel Pans

摘要

Recent studies have documented emissions of ultrafine particles from cooking on electric stoves. A few of these studies show emissions from the electric coil itself (no pan). We have performed more than 100 experiments on an electric coil, or on the coil with an empty stainless steel pan on top, in an attempt to characterize the emissions of fine and ultrafine particles from these two sources. We used a condensation particle counter (CPC) capable of measuring ultrafine particles ＞ 10 nm (UFP10) and a laser photometer to estimate PM2.5 mass concentrations. Since the coil produces most of its particles in the range from 3-10 nm, our studies do not apply to this size range. We find that both the coil and pan produce copious emissions of UFP10 on first heating, but that repeated heating (without intervening cleaning) produces smaller amounts, and with sufficient heating periods, both coil and pan approach zero emissions of UFP10. Cleaning with dishwasher detergent produces quite large UFP10 emissions on first use after the cleaning, but subsequent experiments (without intervening cleaning) again produce smaller and smaller emissions until near-zero emissions are recorded. An older pan that was once used for cooking was also shown after a large number of repeated heatings to approach zero emissions. If the coil or pan is covered between experiments, no UFP10 particles are produced, but if either is left open to the indoor air for a few days, particles are produced. In all these experiments, PM2.5 mass emissions were essentially zero. We conclude that the UFP10 particles are not coming from the electric coil or stainless steel pan themselves, but from some material that is either deposited on them while open to the air or is a residue from cleaning materials or food cooked in the pan.