Methods for measuring concentrations andemission rates of particulate matter (PM) from mechanically ventilated livestock buildings were evaluated in a laboratory facility and in a swine-finishing barn. Concentrations of PM were measured inside the room (room sampling) and at the exhaust duct (exhaust sampling). Concentrations at the exhaust duct were determined using high-volume traverse downstream of the exhaust fan, low-volume traverse downstream of the fan, and fixed sampling upstream and downstream of the fan. The traverse methods, which served as the reference, were conducted under isokinetic conditions; fixed sampling was done under both isokinetic and sub-isokinetic conditions. Compared to the traverse method, both room sampling and exhaust sampling under subisokineticconditions overestimated PM concentrations.Fixed sampling under isokinetic conditions, on the other hand, did not differsignificantly (P>0.05) from the high-volumetraverse method. Thus, isokinetic fixed sampling can be an alternative to the more expensive and time-consuming high-volume PMtraverse method to measure PM concentrationsand emission rates at the exhaust.
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