Ammonia emissions in the United States, European Union, and China derived by high‐resolution inversion of ammonium wet deposition data: Interpretation with a new agricultural emissions inventory (MASAGE_NH3)

Abstract

We use the adjoint of a global 3-D chemical transport model (GEOS-Chem) to optimize ammonia (NH 3 ) emissions in the U.S., European Union, and China by inversion of 2005-2008 network data for NH + 4 wet deposition fluxes. Optimized emissions are derived on a 2 • × 2.5 • grid for individual months and years. Error characterization in the optimization includes model errors in precipitation. Annual optimized emissions are 2.8 Tg NH 3 −N a −1 for the contiguous U.S., 3.1 Tg NH 3 −N a −1 for the European Union, and 8.4 Tg NH 3 −N a −1 for China. Comparisons to previous inventories for the U.S. and European Union show consistency (∼±15%) in annual totals but some large spatial and seasonal differences. We develop a new global bottom-up inventory of NH 3 emissions (Magnitude And Seasonality of Agricultural Emissions model for NH3 (MASAGE_NH3)) to interpret the results of the adjoint optimization. MASAGE_NH3 provides information on the magnitude and seasonality of NH 3 emissions from individual crop and livestock sources on a 0.5 • × 0.5 • grid. We find that U.S. emissions peak in the spring in the Midwest due to corn fertilization and in the summer elsewhere due to manure. The seasonality of European emissions is more homogeneous with a well-defined maximum in spring associated with manure and mineral fertilizer application. There is some evidence for the effect of European regulations of NH 3 emissions, notably a large fall decrease in northern Europe. Emissions in China peak in summer because of the summertime application of fertilizer for double cropping.

Retrieval of ammonia from ground-based FTIR solar spectra

“…NH 3 column total concentrations at Bremen (Blue line) have a seasonal cycle with highest levels during spring, the summer months and autumn. The maximum concentrations occur around April, which is consistent with temporal emission patterns for manure application reported for this region (Friedrich and Reis, 2004;Van Damme et al, 2015b;Paulot et al, 2014). The baseline variability with higher concentrations in summer can be explained by an increase in volatilization rates of NH 3 , emitted from livestock housing, which is driven by animal activity and temperature (Gyldenkaerne et al, 2005).…”

Particulate matter, air quality and climate: lessons learned and future needs

“…Ammonia is mainly emitted by agricultural activities. NH 3 emissions in the United States peak in spring in the Midwest during corn fertilization and elsewhere in summer due to manure (Paulot et al, 2014). In Europe NH 3 emissions are less variable and show a maximum in spring due to fertilizer application (Paulot et al, 2014).…”

“…NH 3 emissions in the United States peak in spring in the Midwest during corn fertilization and elsewhere in summer due to manure (Paulot et al, 2014). In Europe NH 3 emissions are less variable and show a maximum in spring due to fertilizer application (Paulot et al, 2014). NH 3 emission control has been proposed as a cost-effective measure to control secondary inorganic aerosol (SIA), and thus PM levels, both in the United States (Pinder et al, 2007) and in Europe .…”

Inconsistency of ammonium–sulfate aerosol ratios with thermodynamic models in the eastern US: a possible role of organic aerosol

“…The emissions are from the 2011 National Emissions Inventory (NEI) of the US Environmental Protection Agency (EPA), scaled to 2013 as described by Kim et al (2015). There is good confidence in US ammonia emissions, which agree within 20 % in independent bottomup and top-down estimates (Paulot et al, 2014). Most of the domain has an emission ratio higher than 2, indicating excess ammonia.…”