The potential of high temporal resolution automatic measurements of PM composition as an alternative to the filter-based manual method used in routine monitoring.

Under the EU Air Quality Directive (AQD) 2008/50/EC member states are required to undertake routine monitoring of PM composition at background stations. The AQD states for PM speciation this should include at least: nitrate , sulfate , chloride (Cl), ammonium (NH4), sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), elemental carbon (EC) and organic carbon (OC). Until 2017, it was the responsibility of each country to determine the methodology used to report the composition for the inorganic components of PM.

Spatial Distribution of Ammonia Concentrations and Modeled Dry Deposition in an Intensive Dairy Production Region.

Agriculture generates ~83% of total US ammonia (NH) emissions, potentially adversely impacting sensitive ecosystems through wet and dry deposition. Regions with intense livestock production, such as the dairy region of south-central Idaho, generate hotspots of NH emissions. Our objective was to measure the spatial and temporal variability of NH across this region and estimate its dry deposition.

A review of measurements of air-surface exchange of reactive nitrogen in natural ecosystems across North America.

This review summarizes the state of the science of measurements of dry deposition of reactive nitrogen (Nr) compounds in North America, beginning with current understanding of the importance of dry deposition at the U.S. continental scale followed by a review of micrometeorological flux measurement methods.

Toward the improvement of total nitrogen deposition budgets in the United States.

Frameworks for limiting ecosystem exposure to excess nutrients and acidity require accurate and complete deposition budgets of reactive nitrogen (Nr). While much progress has been made in developing total Nr deposition budgets for the U.S.

Long-term trends of wet inorganic nitrogen deposition in Rocky Mountain National Park: Influence of missing data imputation methods and associated uncertainty.

Excess reactive nitrogen (N) deposition is occurring in Rocky Mountain National Park and impacting sensitive ecosystems. In 2006, the National Park Service, State of Colorado, and Environmental Protection Agency established the goal to reduce N deposition to below the ecosystem critical load by 2032. Progress is tracked using 5-year averages of annual wet inorganic nitrogen (IN) deposition measured at Loch Vale, Colorado, by the National Atmospheric Deposition Program (NADP).

Aspects of uncertainty in total reactive nitrogen deposition estimates for North American critical load applications.

Determination of the amount of reactive nitrogen (Nr) deposition in excess of the ecosystem critical load (CL) requires an estimate of total deposition. Because the CL exceedance is used to inform policy decisions, uncertainty in both the CL and the exceedance itself must be understood. In this paper we review the state of the science with respect to the sources of uncertainty in total Nr deposition budgets used for CL assessments in North America and put forth recommendations for research and monitoring to improve deposition measurements and models.

Improved apportionment of ambient PM constituents to sources in Tampa, FL, with pseudo-deterministic receptor model-II.

In 2005, Park et al. developed a new Pseudo-Deterministic Receptor Model (PDRM) to apportion SO2 and ambient particulate matter (PM) constituents to local sources near Tampa Bay. Ambient pollutant measurements were fit to products of emission rates and dispersion factors constrained with a Gaussian Plume Model for individual sources.