Ground Truthing CALPUFF and AERMOD for Odor Dispersion from Swine Barns using Ambient Odor Assessment Techniques

A collaborative research effort by several institutions investigated the dispersion of odors from a swine production facility. Trained human receptors measured downwind odor concentrations from four tunnel-ventilated swine finishing barns near Story City, Iowa, during twenty measurement events conducted between June and November 2004. Odor concentrations were modeled for short time steps using CALPUFF and AERMOD atmospheric dispersion models to compare predicted and measured odor levels. Source emission measurements and extensive micrometeorological data were collected along with ambient odor measurements using the Nasal Ranger® device (St. Croix Sensory, St. Paul MN), Mask Scentometer, odor intensity ratings, and air sample analysis by dynamic triangular forced-choice olfactometry (DTFCO). AERMOD predictions fit the odor measurements slightly better than CALPUFF with predicted concentrations being about half those predicted by CALPUFF. The Mask Scentometer and Nasal Ranger® measurements related best to the dispersion model output, and scaling factors of 3.0 for CALPUFF and 2.4 for AERMOD suggested for the Nasal Ranger® and 0.5 for the Mask Scentometer (both models). Measurements obtained using the Nasal Ranger®, Mask Scentometer, and odor intensity ratings correlated well to each other, had the strongest linear relationships, and provided slopes (measured: modeled) closest to 1.0. Converting intensity ratings to a dilution to threshold concentration did not correlate and relate as well, and this method was deemed less desirable for ambient odor assessment. Collection of ambient air samples for analysis in a olfactometry laboratory displayed poor correlations with other methods and should not be used to assess ambient odors

The dynamics and energetics of tropical temperate troughs over Southern Africa

Water vapour content and transport over southern Africa and adjacent oceans are examined. Early summer rainfall over the northern and central interior of South Africa tends to be associated with baroclinic controls whereas late-summer rainfall is barotropic in origin. This is reflected in the northwesterly water vapour transport from an Atlantic Ocean source by middle and upper tropospheric westerly waves in early summer. A thermally indirect Ferrel cell, indicated-from energetics, COpIU1nSthe· temperate nature of the early-summer atmosphere over southern Africa. Late summer water vapour transport, in contrast, is strongly from the tropics, with' a reduced eddy component, indicating an important tropical control on late SUmmerrainfall especially in terms of fluctuations in the position of the ascending limb of .the Walker cell Over southern Africa. The Hadley cell is of importance to the late summer rainfall in that dry (wet) years are associated with an anomalous cell OVereastern (central) South Africa such that low level vapour transport is southerly (northerly). The anticyclone over the eastern parts of southern Africa, coupled with. a trough over the interior (especially at the 700 hPa pressure level), is important for the introduction of water vapour over the subcontinent in wet and dry years and for tropical-temperate trough case studies. Water vapour source regions differ from early summer (Atlantic Ocean) to late summer (Indian Ocean), which reflects the temperate. control on early and the tropical control on late summer circulation. The convergence of water vapour over southern Africa in wet years and during tropical-temperate troughs is not only important for cloud formation and precipitation, but also for latent heat release associated with convergent water vapour. Diabatic heating decreases the stability of the tropical atmosphere thereby resulting in increased vertical motion. It also forces an anomalous Badley circulation during wet late summers and tropical-temperate trough .cases as a result of complex energy transformations. Heating increases eddy available potential energy which is converted to zonal available potential energy by a thermally indirect circulation found in the tropics. The zonal potential energy is then converted to kinetic energy by the thermally direct Badley cell. Water vapour and its variations are thus important for the precipitation, heating and SUbsequent energy of the subtropical southern African atmosphere,MN (2017

The dynamics and energetics of tropical-temperature troughs over Southern Africa

Water vapour content and transport over southern Africa and adjacent oceans are examined. Early summer rainfall over the northern and central interior of South Africa tends to be associated with baroclinic controls whereas late-summer rainfall is barotropic in origin. This is reflected in the northwesterly water vapour transport from an Atlantic Ocean source by middle and upper tropospheric westerly waves in early summer. A thermally indirect Ferrel cell, indicated-from energetics, COpIU1nSthe· temperate nature of the early-summer atmosphere over southern Africa. Late summer water vapour transport, in contrast, is strongly from the tropics, with' a reduced eddy component, indicating an important tropical control on late SUmmerrainfall especially in terms of fluctuations in the position of the ascending limb of .the Walker cell Over southern Africa. The Hadley cell is of importance to the late summer rainfall in that dry (wet) years are associated with an anomalous cell OVereastern (central) South Africa such that low level vapour transport is southerly (northerly). The anticyclone over the eastern parts of southern Africa, coupled with. a trough over the interior (especially at the 700 hPa pressure level), is important for the introduction of water vapour over the subcontinent in wet and dry years and for tropical-temperate trough case studies. Water vapour source regions differ from early summer (Atlantic Ocean) to late summer (Indian Ocean), which reflects the temperate. control on early and the tropical control on late summer circulation. The convergence of water vapour over southern Africa in wet years and during tropical-temperate troughs is not only important for cloud formation and precipitation, but also for latent heat release associated with convergent water vapour. Diabatic heating decreases the stability of the tropical atmosphere thereby resulting in increased vertical motion. It also forces an anomalous Badley circulation during wet late summers and tropical-temperate trough .cases as a result of complex energy transformations. Heating increases eddy available potential energy which is converted to zonal available potential energy by a thermally indirect circulation found in the tropics. The zonal potential energy is then converted to kinetic energy by the thermally direct Badley cell. Water vapour and its variations are thus important for the precipitation, heating and SUbsequent energy of the subtropical southern African atmosphere,GR 201

Ground Truthing CALPUFF and AERMOD for Odor Dispersion from Swine Barns using Ambient Odor Assessment Techniques

A collaborative research effort by several institutions investigated the dispersion of odors from a swine production facility. Trained human receptors measured downwind odor concentrations from four tunnel-ventilated swine finishing barns near Story City, Iowa, during twenty measurement events conducted between June and November 2004. Odor concentrations were modeled for short time steps using CALPUFF and AERMOD atmospheric dispersion models to compare predicted and measured odor levels. Source emission measurements and extensive micrometeorological data were collected along with ambient odor measurements using the Nasal Ranger® device (St. Croix Sensory, St. Paul MN), Mask Scentometer, odor intensity ratings, and air sample analysis by dynamic triangular forced-choice olfactometry (DTFCO). AERMOD predictions fit the odor measurements slightly better than CALPUFF with predicted concentrations being about half those predicted by CALPUFF. The Mask Scentometer and Nasal Ranger® measurements related best to the dispersion model output, and scaling factors of 3.0 for CALPUFF and 2.4 for AERMOD suggested for the Nasal Ranger® and 0.5 for the Mask Scentometer (both models). Measurements obtained using the Nasal Ranger®, Mask Scentometer, and odor intensity ratings correlated well to each other, had the strongest linear relationships, and provided slopes (measured: modeled) closest to 1.0. Converting intensity ratings to a dilution to threshold concentration did not correlate and relate as well, and this method was deemed less desirable for ambient odor assessment. Collection of ambient air samples for analysis in a olfactometry laboratory displayed poor correlations with other methods and should not be used to assess ambient odors.This proceeding is from International Symposium on Air Quality and Manure Management for Agriculture Conference Proceedings, 13-16 September 2010, Dallas, Texas 711P0510cd.</p