DETERMINATION OF ODOR EMISSION RATES FROM CATTLE FEEDLOTS .2. EVALUATION OF 2 WIND TUNNELS OF DIFFERENT SIZE

Wind tunnels have previously been shown to be a preferred method of sa mpling odour emissions from extensive surfaces. In this paper, odour e mission measurements made at a Queensland feedlot, for the purpose of evaluating the performance of two wind tunnels of different size, are presented. The emission rates measured using the two tunnels (both ope rated at the same average wind speed) are shown to be strongly correla ted, with the large wind tunnel giving emission rates consistently low er that those in the small tunnel by a factor of about 0.8. This diffe rence is presumed to be caused largely by different velocity profiles in the tunnels. The relationship between emission rate and average win d speed is evaluated for both tunnels and found to be consistent with similar relationships deduced from the results of previous studies.