Watching Paint Dry: I/VOC Emissions from Architectural Coatings and their Impact on SOA Formation

Emissions from volatile chemical products (VCPs) are emerging as a major source of anthropogenic secondary organic aerosol (SOA) precursors. Paints and coatings are an important class of VCPs that emit both volatile and intermediate volatility organic compounds (VOCs and IVOCs). In this study, we directly measured I/VOC emissions from representative water-based (latex) and oil paints used in the U.S. Paint I/VOC emissions vary over several orders of magnitude by both solvent and gloss level. Oil paint had the highest emissions (>10^5 microgram/g-paint) whereas low-gloss interior paints (Flat, Satin, and Semigloss) all emitted ~10^2 microgram/g-paint. Emissions from interior paints are dominated by VOCs, whereas exterior-use paints emitted a larger fraction of IVOCs. Extended emissions tests showed that most I/VOC emissions occur within 12-24 hours after paint application, though some IVOC-dominated paints continue to emit for 48 hours or more. We used the emissions measurements to estimate paint I/VOC emissions and subsequent SOA production in the U.S. Total annual paint I/VOC emissions are 168 +/- 15 Mg. This amounts to 291 g/kg of paint used and 0.51 kg/person, which are significantly larger than comparable emissions factors from combustion systems. These emissions contribute to the formation of 8 Mg of SOA annually. Oil paints contribute ~90% of the I/VOC emissions and SOA formation, even though it only accounts for ~20% of paint usage.