Formaldehyde (HCHO) is a toxic air contaminant released indoors from pressed-wood materials and numerous consumer products. Formaldehyde emission data are needed for modeling of indoor personal exposures, health risks, and risk reduction measures. This study determined HCHO emission rates from 55 diverse materials and consumer products under two realistic chamber test conditions, using both time-integrated and continuous real-time measurements. Among dry products, relatively high emissions were found from bare pressed-wood materials made with urea-formaldehyde (UF) resins, and from new (unwashed) permanent press fabrics. UF materials with paper, vinyl, laminate, and other coatings showed HCHO emissions lower by about a factor of 10 than those from bare UF materials. Among wet products, an acid-cured floor finish showed the highest HCHO emissions, greatly exceeding those of any dry product even 24 h after application. Fingernail polish and hardener showed relatively high emission rates, and latex paint and wallpaper relatively low emission rates, but these products emit similar amounts of HCHO because of widely different surface areas of application. Acid-cured finishes, and personal activity patterns and exposures during application of wet products, are key areas for further study.

The U.S. Environmental Protection Agency has established a federal reference method (FRM) for ozone (O 3 ) and allowed for designation of federal equivalent methods (FEMs). However, the ethylene-chemiluminescence FRM for O 3 has been replaced by the UV photometric FEM by most state and local monitoring agencies because of its relative ease of operation. Accumulating evidence indicates that the FEM is prone to bias under the hot, humid, and stagnant conditions conducive to high O 3 formation. This bias may lead to overreporting hourly O 3 concentrations by as much as 20 -40 ppb. Measurement bias is caused by contamination of the O 3 scrubber, a problem that is not detected by dry air calibration. An adequate wet test has not been codified, although a procedure has been proposed for agency consideration. This paper includes documentation of laboratory tests quantifying specific interferant responses, collocated ambient FRM/FEM monitoring results, and smog chamber comparisons of the FRM and FEMs with alternative scrubber designs. As

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