Emissions from Cooking Microwave Popcorn

Abstract

This study characterized chemicals released into a chamber in the process of cooking microwave popcorn. Seventeen types of microwave popcorn from eight different brands were studied. The work proceeded in two phases: phase one investigated chemicals emitted during popping and opening, phase two investigated chemicals emitted at discrete intervals from 0–40 minutes post-pop opening. The research was performed using a microwave oven enclosed in a chamber with ports for air sampling of particulate matter (PM) and volatile organic compounds (VOCs). VOCs in the air samples were identified and quantified using gas chromatography/mass spectrometry (GC/MS). PM was characterized using both an aerodynamic particle sizer (APS) and a scanning mobility particle sizer (SMPS) to cover a full range of emitted sizes. The compounds measured during popping and opening included butter flavoring components such as diacetyl, butyric acid, acetoin, propylene glycol, 2-nonanone, and triacetin and bag components such as p-xylene and perfluorinated alcohol 8:2 telomer. The greatest chemical quantity is emitted when the bag is opened post-popping; more than 80% of the total chemical emissions occur at this time.

Keywords:

• air sampling
• diacetyl
• perfluorinated compounds
• volatiles

ACKNOWLEDGEMENTS

The authors would like to thank Shirley Wasson, Scott Moore, Betsy Howard, and John Holland of the U.S. EPA for their support of this project. This project was funded by a U.S. EPA National Risk Management Laboratory internal grant.

This article not subject to United States copyright law.

Notes

∗ Indicates that the chemical is present in less than 75% of all popcorn types, where type is defined by brand and flavor.

¹ The aerodynamic diameter is an equivalent diameter that standardizes for particle shape and density. For a particular particle, the aerodynamic diameter is defined as the diameter of a spherical particle with a density of 1 g/cm³ that has the same settling velocity as the particle (Hinds, 1999). The mass median aerodynamic diameter (MMAD) is the calculated aerodynamic diameter where, by weight, 50% of the particles will be larger than the MMAD and 50% of the particles will be smaller than the MMAD (U.S. Environmental Protection Agency, 2006).