Formaldehyde, less volatile aldehydes, and terpene hydrocarbons are generally the predominant air contaminants in new manufactured and site-built houses. This study was conducted to identify the major sources of these compounds in a typically constructed, new manufactured house and to evaluate several source reduction practices. Specimens of materials used within the house were collected. These were individually pre-conditioned for 19 +/- 4 days, and tested for emissions of formaldehyde and other target compounds using small-scale chambers. Several cabinetry materials, passage doors, and the plywood subfloor were the predominant sources of formaldehyde and other aldehydes. The plywood subfloor was the predominant terpene source. Whole-house emission rates for combined materials were predicted based on the emission factors and the corresponding material quantities. These predicted rates were compared with whole-house emission rates derived from measurements made at the house 3 months after its installation. For 10 of 14 target compounds including formaldehyde, the predicted and derived rates were within a factor of two. Four emission barriers applied to plywood were shown to reduce emission factors for formaldehyde, hexanal, and other aldehyde