Brief Summary of Minutes of Annual Meeting

See Attached

NC1213: Sources and fate of ammonia across the landscape

The main objectives of this project are to:

1: Better understand and quantify ammonia emissions from crop and livestock across spatial scales.

2: Characterize the magnitude and variability of ammonia deposition in natural and agricultural landscapes.

3: Understand the transport and fate of NH3 emissions and its impact on PM formation and reactive nitrogen deposition.

The U.S. Corn Belt is a global hotspot of atmospheric ammonia (NH3), a gas known to adversely impact the environment and human health. We combine hourly tall tower (100 m) measurements and bi-weekly, spatially distributed, ground-based observations from the Ammonia Monitoring Network with the U.S. National Emissions Inventory (NEI) and WRF-Chem simulations to constrain NH3 emissions from April-September, 2017-2019. We show that: (1) NH3 emissions peaked from May to July and were 1.6 to 1.7 times the annual NEI average; (2) average growing season NH3 emissions from agricultural lands were remarkably similar across years (3.27 to 3.64 nmol m^-2 s^-1), yet showed substantial episodic variability driven by meteorology and land management; (3) dry deposition was 40% of gross emissions from agricultural lands and exceeded 100% of gross emissions in natural lands. Our findings provide an important benchmark for evaluating future NH₃ emissions and mitigation efforts.

 "A multi-year constraint on ammonia emissions and deposition within the U.S. Corn Belt", C. Hu, T.J. Griffis, A. Frie, J.M. Baker, J.D. Wood, D.B. Millet, Z. Yu, X. Yu, and A.C. Czarnetzki (Geophysical Research Letters, 2021, 48, e2020GL090865. https://doi.org/10.1029/2020GL090865)

1. Beltran, I., van der Weerden, T.J., Alfaro, M.A., Amon, B., de Klein, C.A.M., Grace, P., Hafner, S., Hassouna, M. Hutchings, N., Krol, D.J., Leytem, A.B., Noble, A., Salazar, F., Thorman, R.E., and Velthof, G.L. DataMan: A global database of nitrous oxide and ammonia emission factors for excreta deposited by livestock and land-applied manure. Environ. Qual. 2021. http://dx.doi.org/10.1002/jeq2.20186
2. Rotz, C.A., R.  Stout, B. Leytem, G. Feyereisen, H. Waldrip, G. Thoma, M. Holly, D. Bjorneberg, J. Baker, P. Vadas and P. Kleinman. Environmental assessment of United States dairy farms. J. Cleaner Prod. 2021. 315:128153 https://doi.org/10.1016/j.jclepro.2021.128153
3. VanDerWeerden, T.J., Noble, A., De Klein, C.A.M., Hutchings, N., Thorman, R.E., Alfaro, M.A., Amon, B., Beltran, I., Grace, P., Hassouna, M., Krol, D.J., Leytem, A.B., Salazar, F., and Velthof, G.L. Ammonia and nitrous oxide emission factors for excreta deposited by livestock and land-applied manure. 2021. Environ. Qual. DOI: 10.1002/jeq2.20259
4. Leytem, A.B., P. Williams, S. Zuidema, A. Martinez, Y.L. Chong, A. Vincent, A. Vincent, D. Cronan, A. Kliskey, J.D. Wulfhorst, L. Alessa, and D. Bjorneberg. Cycling phosphorus and nitrogen through cropping systems in an intensive dairy production region. Agronomy. 2021. 11,1005 https://doi.org/10.3390/agronomy11051005

5. C. Hu, T.J. Griffis, A. Frie, J.M. Baker, J.D. Wood, D.B. Millet, Z. Yu, X. Yu, and A.C. Czarnetzki. A multi-year constraint on ammonia emissions and deposition within the U.S. Corn Belt. Geophysical Research Letters, 2021, 48, e2020GL090865. https://doi.org/10.1029/2020GL090865