Characterization and Graphical Visualization of Fluxes of Oxides of Nitrogen from Agricultural Soils in North Carolina
Abstract
Oxides of nitrogen (NOx = NO + NO2) play a central role in tropospheric photochemistry. Natural biogenic emissions of NOx from soils are usually considered to be only a small fraction of the anthropogenic emissions, but the source strength is not well known. Field measurements of NOx were made in two seasons (summer and winter) in an agriculturally-managed field in North Carolina. The NO flux estimates were used to produce a graphical representation of the spatial distribution of ozone precursors in the state, and to assess the magnitude of these biogenic soil NO emissions as a percentage of the total NO emissions in the state. A significant negative correlation between NO flux and ambient O3 concentration, supports the hypothesis that soil emissions of NO contribute to local production of O3 in rural areas. The winter measurements suggest that significant fluxes are generated during fallow periods when the plant residue is mixed back into the soil, a common agricultural practice. Using the assumption that the calculated NO fluxes are representative of those across North Carolina, these fluxes were used to develop graphical displays of the spatial distribution of soil NO emissions in the state, with a county spatial resolution. These NO emission estimates were compared to other values in the literature. Estimates of the soil emission of NO as a percentage of total (all sources) NO emission in the state were compared to the current input values used in the Regional Oxidants Model (ROM). The values calculated from these measurements are significantly larger than those currently used in the ROM.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1994
- Accession Number
- ADA284491
Entities
People
- Benny D. Holbrook
Organizations
- Air Force Institute of Technology