Evaluation of Potential Exposure to Formaldehyde Air Emissions from a Washing Machine Using the IAQX Model

ABSTRACT

Consumers may be exposed to formaldehyde during the use of liquid laundry detergent containing a preservative. The primary objective of this analysis was to present an approach to predict formaldehyde air emissions from a washing machine and the subsequent vapor concentrations in the laundry room air using the U.S. Environmental Protection Agency's (USEPA's) Simulation Tool Kit for Indoor Air Quality and Inhalation Exposure, referred to as the IAQX model. A second objective was to identify key model input parameters for formaldehyde. This analysis recommends use of the IAQX emission Model 52 because it provided the best estimates by correlating the formaldehyde evaporation to the Henry's law constant and to the overall gas-phase mass transfer coefficient that was based on washing machine experimental results. The mass balance estimated that 99.7% of the initial formaldehyde mass in the washing machine was discharged down the drain with the wash water and the rest of the formaldehyde was emitted to the air from the top loading washing machine and the hot air clothes dryer. The predicted formaldehyde exposures were acceptable and much lower than the USEPA proposed targets for non-cancer effects and cancer risk.

Key Words:

• air emissions
• evaporation
• inhalation exposure
• formaldehyde
• washing machine

ACKNOWLEDGMENTS

The authors thank the following individuals for providing guidance and helpful suggestions for this study: Hamukh C. Shah of the American Chemistry Council; Adrian Krygsman of Troy Corporation; William B. Woods of ISP Corporation; Zhishi Guo, Xiaoyu Liu, and Mark Mason of the USEPA National Risk Management Research Laboratory; and Cynthia Howard-Reed of the National Institute of Standards and Technology.