Impact of Flame Retardants on the Physical and Chemical Properties of Residential Combustion Aerosol from Furniture Foams

Riley Weatherholt, Bailey Bowers, Amila De Silva, Heather Stapleton, Carrie McDonough, RYAN SULLIVAN, Carnegie Mellon University

     Abstract Number: 565
     Working Group: Burning Questions of Aerosol Emissions, Chemistry, and Impacts from Wildland-Urban Interface (WUI) Fires

Abstract
To meet flammability standards initially introduced in the 1970s, furniture manufacturers often add mixtures of chemical flame retardants to furniture foams. Flame retardants, including brominated organics and chlorinated organophosphates, are known to exhibit a wide range of toxic effects, but little is known about the effects these flame retardants have on the chemical and physical properties of the resulting emissions when residential fires occur. Since flame retardants work by making combustion less efficient, we hypothesize that foams treated with flame retardants will yield higher mass concentrations of combustion aerosol as well as gas and particle phase emission of potentially toxic byproducts resulting from transformations of the flame retardants. We combusted foams with and without flame retardants in a steel chamber, collected the emissions on quartz filters and polyurethane gas samplers, characterized the aerosol concentration and size distributions with a scanning mobility particle sizer (SMPS), and evaluated the elemental to organic carbon ratio (EC/OC) of the aerosol collected on filters. The foams included authentic commercial foams as well as a manufacturer’s sample with and without Firemaster 600, a common mixture of chlorinated organophosphate esters and brominated flame retardants. We analyzed filter extracts with gas chromatography-mass spectrometry (GC-MS) and ultra-high performance liquid chromatography mass spectrometry (UPLC-QTOF-MS), and compared the contents of the emissions to extracts from the intact foams. We found that combustion of flame retardant laden foams releases intact flame retardant molecules, such as tris(2-chloroisopropyl)phosphate (TDCIPP) and 2-ethylhexyl 2,3,4,5-tetrabromobenzoate. While it is generally thought that organophosphate flame retardants stay within or on the surface of the foam, polymerizing to create a char layer that suppresses combustion, we observe that up to 4% of the FR mass in the foam is released during combustion. We observed drastically different mixtures of flame retardants between commercial products, indicating that chemically complex mixtures of halogenated flame retardants are likely released during residential fires. Furthermore, halogenated transformation products of flame retardants were also measured. Our work suggests that the emission of intact flame retardants and halogenated byproducts would drive human exposure to harmful gas and aerosol emissions such as during and following urban fires.