AIR QUALITY AND EMISSION MEASUREMENT METHODOLOGY AT SWINE FINISHING BUILDINGS

Abstract

Reliable measurements of air quality and emissions at large livestock buildings with inherently large spatial andtemporal variations of pollutant concentrations are relatively difficult and expensive. Appropriate methodologies for suchmeasurements are not readily apparent and techniques and strategies vary widely. Several important technical issues needto be addressed by an air pollutant emission measurement plan. This article describes comprehensive field measurements ofindoor air quality and air pollutant emissions at eight commercial swine finishing buildings.<br><br>The objective of the field test was to evaluate the effect of a manure additive on concentration and emission of ammonia,hydrogen sulfide, and odor. Continuous measurements of gases, ventilation rate, building static pressure, inside and outsidetemperature and humidity, and wind speed and direction were conducted at four naturallyventilated buildings and fourmechanicallyventilated buildings. Air was pumped continuously from inside each building into airsampling manifolds. Oneair stream was drawn from beneath the floor to assess pit headspace air concentrations. Another air stream was drawn fromventilation exhaust points to assess inside gas concentrations and building emission rates. Gas analyzers were switchedbetween sampling manifolds on 10 to 15min sampling intervals. Ammonia was measured with chemiluminescence NOxanalyzers after conversion to nitric oxide. Hydrogen sulfide was converted to sulfur dioxide and measured withpulsedfluorescence, sulfur dioxide analyzers. Odor samples were collected in bags and evaluated using olfactometry. Gasand odor emission rates were determined by multiplying mean gas concentrations in the exhaust air by ventilation airflowrates. Ventilation rates of naturallyventilated buildings were estimated using sensible heat and carbon dioxide balances.Ventilation rates of mechanicallyventilated buildings were determined by monitoring wall fan operation and directlymeasuring airflow of some variablespeed pit fans with fullsize impeller anemometers. Labor and equipment requirements,pitfalls, problems, and solutions to problems of field studies are discussed. Several recommendations for future studies of thistype were developed based on experience gained during this measurement campaign.