Secondary organic aerosols from ozone-initiated reactions with emissions from wood-based materials and a green paint

This study examined the formation and growth of secondary organic aerosols (SOA) generated when ozone was added to a 1 m(3) glass chamber that contained either pine shelving, oriented strand board (OSB), beech boards, or beach boards painted with an eco paint. The experiments were conducted at close to real-world conditions: the chamber was ventilated at similar to 0.5 air changes/h; the loadings (exposed surface of building materials to chamber volume) were in the range of 1-2.5 m(2) m(-3); and the initial O-3 concentrations were between 15 and 40 ppb. Throughout each experiment particles were measured with both a condensation nuclei counter and an optical counter, while terpenes Were measured before and after the ozone exposure period using sorbent tubes. The pine boards emitted primarily alpha-pinene and 3-carene and lesser amounts of 5 other terpenes; when 03 was introduced, the particle counts increased dramatically: the mass concentration reached similar to 15 mu g m(-3) at similar to 20 ppb O-3, and similar to 95 mu g m(-3) at similar to 40 ppb O-3. The OSB emitted primarily limonene and alpha-pinene. Although the particle counts increased when O-3 was introduced, the increase was not as large as anticipated based on the terpene concentrations. The beech boards emitted negligible quantities of terpenes, and the introduction of O-3 resulted in almost no increase in the particle concentration. Beech boards painted with an eco paint emitted large amounts of limonene and lesser amounts of carvone; upon introduction of O-3 the particle counts increased sharply with the mass concentration reaching similar to 20 mu g m(-3) at similar to 15 ppb O-3 and similar to 160 mu g m(-3) at similar to 35 ppb O-3. These experiments demonstrate that the emission of terpenes and potential generation of SOA varies greatly among different types of wood and pressed wood materials. in the case of the pine boards and painted beech boards, the SOA concentrations generated at modest O-3 concentrations approach or exceed current guideline levels for PM2.5 established by the US EPA and the World Health Organization. (C) 2008 Elsevier Ltd. All rights reserved.