Nitrogen oxides (NOx) and their reaction products (i.e. NOy) are an important precursor to ozone and particulate matter pollution and can impact nutrient loads to aquatic ecosystems. NOx emissions come from a variety of anthropogenic and natural sources including onroad vehicles, nonroad equipment, power plants, other combustion sources, wildland fires, soils, and lightning. Some recent studies in the scientific literature have found discrepancies between concentrations predicted by photochemical models and ambient measurement. These discrepancies could be attributed to emissions, meteorological model transport, model chemistry, or deposition processes or related to uncertainties in the measurements themselves. This session seeks submissions of new research results which use ambient measurements (e.g. routine ambient monitoring network data, near-road and tunnel measurement, special field campaign data, satellite data and deposition measurements) to characterize, evaluate, or constrain processes impacting the total modeled NOy budget. In addition, this session welcomes submissions which use new data or methods to more accurately characterize NOx emissions or photochemical model processes. Submissions along the following topics all fit within the scope of this session:
- Updates to emissions and implications for budgets
- Ambient constraint methodologies and applications
- Sampling methods and uncertainties
- Meteorological and seasonal factors
- Reaction and deposition lifetimes in the atmospheric Boundary Layer
- Removal processes, dry and wet deposition
Preference will be given to abstracts that make a clear connection between emissions or model processes and observations.