Mobile Measurements of Atmospheric Ammonia in Northeastern Colorado

Yixing Shao1, Jeffrey L. Collett, Jr.2 and Katherine B. Benedict3

The spatial and temporal variability of ammonia is not well characterized in regions like northeastern Colorado where there are large agricultural sources adjacent to urban and remote areas. Northeastern Colorado is of interest since it is home to Rocky Mountain National Park (RMNP), a protected area experiencing the effects of increased nitrogen deposition. To protect the park from increasing nitrogen deposition it is crucial to understand the degree to which the urban and agricultural sources are impacting RMNP, as well as how meteorological conditions are influencing the ammonia concentrations and nitrogen deposition in the park. Mobile measurements of ammonia were made in June 2016 to examine the spatial variability of ammonia at high-time resolution. These data, together with modeling results from the Hybrid Single Particle Lagrangian Integrated Trajectory Model (HYSPLIT), will be used to investigate the transport of ammonia across the region. From previous observations it is unclear whether distinct plumes of ammonia are being transported over large distances or whether regional ammonia concentrations are relatively homogeneous. The combination of these measurements and modeling results will provide a clearer picture of how ammonia-rich air parcels in the eastern plains of Colorado are transported and contribute to nitrogen deposition in the park.


1Colorado State University,
2Colorado State University,
3Colorado State University,