Monitoring of odour occurrence in the vicinity of swine farms by resident observers - Part II: impact of weather conditions on odour occurrence

Abstract

Guo, H., Feddes, J., Dehod, W., Lague, C. and Edeogu, I. 2006. Monitoring of odour occurrence in the vicinity of swine farms by resident-observer - Part II: Impact of weather conditions on odour occurrence. Canadian Biosystems Engineering/Le genie des biosystemes au Canada 48 : 6.23 - 6.29. The impact of weather conditions including wind speed and atmospheric stability on odour occurrences as reported by the resident observers in the vicinity of intensive swine farms was studied. The results indicated that the number of odour events had an inverse linear relationship with the wind speed. High intensity odours were detected at distances up to 5.8 km from the swine farms at wind speeds up to 9.4 m/s. Swine odours were detected under all atmospheric stability classes except stability class A. Most odour events (61.7%) were detected under neutral atmospheric stability class D while only 15.0% were detected under stable atmospheric conditions. Stable atmospheric conditions occurred the least in the period from May to August, yet this period had the highest number of odour events. Hence, atmospheric stability was not the main determinative factor for odour detection frequencies. Other factors, such as increased odour emissions from outside manure storage during the warm season and the increased frequency and duration of time observers spend outside of their residences, escalating the probability they would detect an odour, seem to have greater impact on odour detection frequencies. Most observers who detected a high number of odour events were located downwind of the swine farms from the directions with the highest frequencies of neutral and stable atmospheric conditions. The results of this study suggest that odour occurrences as experienced by the resident observers varied with season, time of day, location, weather conditions, and availability of