Odour and gas release from anaerobic lagoons for treating swine waste affect air quality in neighbouring communities but rates of release are not well documented. A buoyant convective flux chamber (BCFC) was used to determine the effect of lagoon loading rate on measured odour and gas releases from two primary lagoons at a simulated wind speed of 1.0 m s-1. Concentrations of ammonia (NH3), hydrogen sulfide (H2S), carbon dioxide (CO2), sulfur dioxide (SO2), and nitric oxide (NO) in 50-L air samples were measured. A panel of human subjects, whose sensitivity was verified with a certified reference odorant, evaluated odour concentration, intensity, and hedonic tone. Geometric mean odour concentrations of BCFC inlet and outlet samples and of downwind berm samples were 168+or-44 (mean+or-95% confidence interval), 262+or-60, and 114+or-38 OUE m-3 (OUE, European odour unit, equivalent to 123 micro g n-butanol), respectively. The overall geometric mean odour release was 2.3+or-1.5 OUE s-1 m-2 (1.5+or-0.9 OU s-1 m-2). The live mass specific geometric mean odour release was 13.5 OUE s-1 AU-1 (animal unit=500 kg live body mass). Overall mean NH3, H2S, CO2 and SO2 releases were 101+or-24, 5.7+or-2.0, 852+or-307, and 0.5+or-0.4 micro g s-1 m-2, respectively. Nitric oxide was not detected. Odour concentrations were directly proportional to H2S and CO2 concentrations and odour intensity, and inversely proportional to hedonic tone and SO2 concentration (P<0.05). Releases of NH3, H2S, and CO2 were directly proportional (P<0.05) to volatile solids loading rate (VSLR).