Ultrafine Particle Emissions from 'Non-stick' Coated Cookware

摘要

Cookware coated with polytetrafluorethylene (PTFE) (brand name "Teflon") is widely used because food is easily cleaned from its surface. However, when heated, the coating degrades and can release several fluorinated compounds, including perfluorooctanoic acid (PFOA). PFOA is globally dispersed and occurs in the blood of many persons. It has been associated with kidney and testicular cancer in human populations living near a plant manufacturing PFOA. Previous studies have noted birds dying on exposure to fumes from pans heated to 202 °C. Few studies have reported on ultrafine particles released from coated pans. We report here on emission rates of ultrafine particles from coated pans heated to temperatures in the range of 120-180 °C. Two coated pans (one used, one new) were heated for 4-6 minutes on the heating coil of an electric burner that had been reheated multiple times until it no longer emitted ultrafine particles (UFP) ＞ 10 nm. A TSI Model 3007 was used to count particles ＞10 nm. The temperature of the burner coil was measured throughout the heating period using a probe directly contacting the coil. Alternatively, the temperature of the pan was measured using the same probe. The pan was reheated without cleaning it in successive experiments of the same duration (usually 6 minutes) until the peak number of particles emitted reached an asymptote. It was observed that higher levels were produced following washing the pan as recommended in warm soapy water, perhaps due to a film left by the detergent. Both pans tested emitted UFP ＞ 10 nm at a rate of 0.88-1.1 × 10~(12) particles min~(-1). This was sufficient to achieve concentrations of 250,000 cm~(-3) in a small room of 25 m3 volume. Additional experiments in two homes with heated cookware were performed to confirm these findings.