BAJWA, KANWARDEEP SINGH. Measurements and Modeling of Emissions, Dispersion and Dry Deposition of Ammonia from Swine Facilities. (Under the direction of Dr. Viney P. Aneja and Dr. S. Pal Arya). Ammonia has recently gained importance for its increasing atmospheric concentrations and its role in the formation of aerosols. Studies have shown increasing atmospheric concentration levels of NH3 and N...

The input of nitrogen (N) to ecosystems has increased dramatically over the past decades. While total (wet + dry) N deposition has been extensively determined in temperate regions, only very few data sets of N wet deposition exist for tropical ecosystems, and moreover, reliable experimental information about N dry deposition in tropical environments is lacking. In this study we estimate dry and...

Comment: This manuscript presents a modeling study on the effects of anthropogenic nitrogen deposition on ozone pollution through surface-atmosphere exchanges. The Authors combine GEOS-Chem with CLM to produce an interesting, smart modeling experiment to study several processes (e.g. soil NOx, biogenic VOC, LAI, dry deposition velocity, etc) that affect surface ozone. They find that enhance atm...

Atmospheric deposition of the major elements was estimated from throughfall and bulk deposition measurements on 13 plots of the Swiss Long-Term Forest Ecosystem Research (LWF) between 1995 and 2001. Independent estimates of the wet and dry deposition of nitrogen (N) and sulfur (S) on these same plots were gained from combined simplified models. The highest deposition fluxes were measured at Nov...

Two modified passive samplers were evaluated at multiple field locations. The sampling rate (SR) of the modified polyurethane foam (PUF)-disk passive sampler for total gaseous mercury (TGM) using gold-coated quartz fiber filters (GcQFF) and gaseous oxidized mercury (GOM) using ion-exchange membranes (IEM) were 6.4 ± 1.4 and 15.3 ± 0.3 m(3) day(-1), respectively. The relative percent difference ...

Atmospheric dry deposition is typically modelled using an average roughness length, which depends on land use. This classical roughness-length approach cannot account for the spatial variability of dry deposition in complex settings such as urban areas. Urban canopy models have been developed to parametrise momentum and heat transfer. We extend this approach here to mass transfer, and a new dry...

The main purpose for this study was to monitor ambient air particles and metallic elements (Mn, Fe, Zn, Cr, and Cu) in total suspended particulates (TSPs) concentration, dry deposition at three characteristic sampling sites of central Taiwan. Additionally, the calculated/measured dry deposition flux ratios of ambient air particles and metallic elements were calculated with Woods models at these...

A tracer model, DREAM (the Danish Rimpuff and Eulerian Accidental release Model), has been developed for modelling transport, dispersion and deposition (wet and dry) of radioactive material from accidental releases, as the Chernobyl accident. The model is a combination of a Lagrangian model, that includes the near source dispersion, and an Eulerian model describing the long-range transport. The...

In this study, we present the response of model results to different scientific treatments in an effort to quantify the uncertainties caused by the incomplete understanding of mercury science and by model assumptions in atmospheric mercury models. Two sets of sensitivity simulations were performed to assess the uncertainties using modified versions of CMAQ-Hg in a 36-km Continental United State...

Atmospheric sulfur (S) deposition via precipitation, particles and gases was investigated at ten sites in Northern China. Measurements were performed continuously between December 2007 and November 2010. The total S deposition flux in the target area ranged from 35.0 to 100.7 kg S ha−1 yr−1, noticeably higher than the values documented in Europe, North America, and East Asia. The tensite, 3-yr ...