The levels of malodorous compounds in the air above an anaerobic lagoon of a large swine farrowing operation were measured. Compounds were adsorbed onto silicone stir bars and retained compounds measured by gas chromatography-mass spectroscopy. Equilibration times were previously determined by experiments in which the stir bars were preloaded with a series of standard compounds varying in polarity and boiling point. Equilibration time for stir bars in air were found to be most related to compound boiling point whereas equilibration time for stir bars in water had been found previously to be correlated with compound polarity. While the samplers were deployed above the lagoon, air samples were also passed at a rate of 50 mL min-1 through thermal desorption tubes containing a bed of Tenax TA in an attempt to relate the concentration of specific mal-odorants with the level of compounds retained on the silicone stir bars. While the air samples were collected, meteorological measurements were also recorded including wind speed and direction, wind speed at two heights above the lagoon surface, air and water temperatures and relative humidity.