Air samples for formaldehyde and acetaldehyde were collected on treated silica-gel cartridges (P/N WAT047205, Waters Corp.) using separate pumps. Sampling flow rates were L min-1 collected over 15 min to 30 min yielding sample volumes of about 30 L to 60 L. Each cartridge was extracted with 2 mL of acetonitrile. Extracts were analyzed by high- performance liquid chromatography with a diode array detector at a wavelength of 365 nm following ASTM D 5197 (ASTM, 1997a). Extract concentrations were determined from multi- point calibrations of external standard mixtures. .
