Review of "Source regions contributing to excess reactive nitrogen deposition in the Greater Yellowstone Area (GYA) of the United States" by Rui Zhang et al.

2018 ◽  
Author(s):  
Anonymous
Keyword(s):  
United States ◽  
Nitrogen Deposition ◽  
The United States ◽  
Reactive Nitrogen ◽  
Source Regions ◽  
Greater Yellowstone Area ◽  
Greater Yellowstone

scholarly journals Source regions contributing to excess reactive nitrogen deposition in the Greater Yellowstone Area (GYA) of the United States

2018 ◽  
Vol 18 (17) ◽  
pp. 12991-13011 ◽  
Author(s):  
Rui Zhang ◽  
Tammy M. Thompson ◽  
Michael G. Barna ◽  
Jennifer L. Hand ◽  
Jill A. McMurray ◽  
...  
Keyword(s):  
United States ◽  
Air Quality ◽  
Source Apportionment ◽  
The United States ◽  
Reactive Nitrogen ◽  
Snake River ◽  
Source Regions ◽  
Greater Yellowstone Area ◽  
Northern Utah ◽  
Greater Yellowstone

Abstract. Research has shown that excess reactive nitrogen (Nr) deposition in the Greater Yellowstone Area (GYA) of the United States has passed critical load (CL) thresholds and is adversely affecting sensitive ecosystems in this area. To better understand the sources causing excess Nr deposition, the Comprehensive Air Quality Model with Extensions (CAMx), using Western Air Quality Study (WAQS) emission and meteorology inputs, was used to simulate Nr deposition in the GYA. CAMx's Particulate Source Apportionment Technology (PSAT) was employed to estimate contributions from agriculture (AG), oil and gas (OG), fire (Fire), and other (Other) source sectors from 27 regions, including the model boundary conditions (BCs) to the simulated Nr for 2011. The BCs were outside the conterminous United States and thought to represent international anthropogenic and natural contributions. Emissions from the AG and Other source sectors are predominantly from reduced N and oxidized N compounds, respectively. The model evaluation revealed a systematic underestimation in ammonia (NH3) concentrations by 65 % and overestimation in nitric acid concentrations by 108 %. The measured inorganic N wet deposition at National Trends Network sites in the GYA was overestimated by 31 %–49 %, due at least partially to an overestimation of precipitation. These uncertainties appear to result in an overestimation of distant source regions including California and BCs and an underestimation of closer agricultural source regions including the Snake River valley. Due to these large uncertainties, the relative contributions from the modeled sources and their general patterns are the most reliable results. Source apportionment results showed that the AG sector was the single largest contributor to the GYA total Nr deposition, contributing 34 % on an annual basis. A total of 74 % of the AG contributions originated from the Idaho Snake River valley, with Wyoming, California, and northern Utah contributing another 7 %, 5 %, and 4 %, respectively. Contributions from the OG sector were small at about 1 % over the GYA, except in the southern Wind River Mountain Range during winter where they accounted for more than 10 %, with 46 % of these contributions coming from OG activities in Wyoming. Wild and prescribed fires contributed 18 % of the total Nr deposition, with fires within the GYA having the highest impact. The Other source category was the largest winter contributor (44 %) with high contributions from California, Wyoming, and northern Utah.

scholarly journals Source regions contributing to excess reactive nitrogen deposition in the Greater Yellowstone Area (GYA) of the United States

2018 ◽  
Author(s):  
Rui Zhang ◽  
Tammy M. Thompson ◽  
Michael G. Barna ◽  
Jennifer L. Hand ◽  
Jill A. McMurray ◽  
...  
Keyword(s):  
United States ◽  
Air Quality ◽  
Source Apportionment ◽  
The United States ◽  
River Valley ◽  
Snake River ◽  
Source Regions ◽  
Greater Yellowstone Area ◽  
Northern Utah ◽  
Greater Yellowstone

Abstract. Research has shown that excess reactive nitrogen (Nr) deposition in the Greater Yellowstone Area (GYA) of the United States has passed critical load thresholds and is adversely affecting sensitive ecosystems in this area. To better understand the sources causing excess Nr deposition, the Comprehensive Air Quality Model with extensions (CAMx), using Western Air Quality Study (WAQS) emission and meteorology inputs, was used to simulate Nr deposition in the GYA. CAMx's Particulate Source Apportionment Technology (PSAT) was employed to estimate contributions from agriculture (AG), oil and gas (OG), fire (Fire), and other (Other) source sectors from 27 regions, including the model boundary conditions (BC) representative of international contributions, to the simulated Nr for 2011. Emissions from the AG and Other source sectors are predominantly from reduced N and oxidized N compounds, respectively. The model evaluation revealed a systematic underestimation in ammonia (NH3) concentrations by 65 % and overestimation in nitric acid concentrations by 108 %. The measured inorganic N wet deposition at National Trend Network sites in the GYA was overestimated by 31–49 %, due at least partially to an overestimation of precipitation. Source apportionment results showed that the AG sector was the single largest contributor to the GYA total Nr deposition, contributing 34 % on an annual basis. Seventy-four percent of the AG contributions originated from the Idaho Snake River valley, with Wyoming, California, and northern Utah contributing another 7 %, 5 %, 20 and 4 % respectively. Contributions from the OG sector were small at about 1 % over the GYA, except in the southern Wind River Mountain Range during winter where they accounted for more than 10 %, with 46 % of these contributions coming from OG activities in Wyoming. Wild and prescribed fires contributed 18 % of the total Nr deposition, with fires within the GYA having the highest impact. The five largest source area contributions to the annual total Nr deposition in the GYA were 1) the Snake River valley (3 8 % with AG 68 %, OG 2 %, Fire 15 %, and Other 16 %); 2) BC (21 %); 3) Wyoming (12 % with AG 19 %, OG 5 %, Fire 38 %, and Other 39 %); 4) California (7 % with AG 26 %, OG 1 %, Fire 14 %, and Other 59 %); and 5) northern Utah (6 % with AG 25 %, OG 2 %, Fire 10 %, and 25 Other 63 %). These results suggest that Nr deposition over the GYA, especially in the western region, was above the critical loads for sensitive ecosystems, and 22 AG from the Snake River valley was the largest contributor. Distant source regions were also important, with large contributions from the BC, i.e., international source regions.

scholarly journals Greater Contribution From Agricultural Sources to Future Reactive Nitrogen Deposition in the United States

2020 ◽  
Vol 8 (11) ◽  
Author(s):  
Yilin Chen ◽  
Huizhong Shen ◽  
Jhih‐Shyang Shih ◽  
Armistead G. Russell ◽  
Shuai Shao ◽  
...  
Keyword(s):  
United States ◽  
Nitrogen Deposition ◽  
The United States ◽  
Reactive Nitrogen

scholarly journals Present and future nitrogen deposition to national parks in the United States: critical load exceedances

2013 ◽  
Vol 13 (4) ◽  
pp. 9151-9178 ◽  
Author(s):  
R. A. Ellis ◽  
D. J. Jacob ◽  
M. Payer ◽  
L. Zhang ◽  
C. D. Holmes ◽  
...  
Keyword(s):  
United States ◽  
Critical Load ◽  
Nitrogen Deposition ◽  
National Parks ◽  
The United States ◽  
N Deposition ◽  
Fuel Combustion ◽  
Nox Emissions ◽  
The West ◽  
Us National Parks

Abstract. National parks in the United States are protected areas wherein the natural habitat is to be conserved for future generations. Deposition of anthropogenic nitrogen (N) transported from areas of human activity (fuel combustion, agriculture) may affect these natural habitats if it exceeds an ecosystem-dependent critical load (CL). We quantify and interpret the deposition to Class I US national parks for present-day and future (2050) conditions using the GEOS-Chem global chemical transport model with 1/2° × 2/3° horizontal resolution over North America. We estimate CL values in the range 2.5–5 kg N ha−1 yr−1 for the different parks with the goal of protecting the most sensitive ecosystem receptors. For present-day conditions, we find 24 out of 45 parks to be in CL exceedance and 14 more to be marginally so. Many of these are in remote areas of the West. Most (40–85%) of the deposition originates from NOx emissions (fuel combustion). We then project future changes in N deposition using the Representative Concentration Pathway (RCP) emission scenarios for 2050. These feature 52–73% declines in US NOx emissions relative to present but 19–50% increases in US ammonia (NH3) emissions. Nitrogen deposition at US national parks then becomes dominated by domestic NH3 emissions. While deposition decreases in the East relative to present, there is little progress in the West and increases in some regions. We find that 17–25 US national parks will have CL exceedances in 2050 based on the RCP scenarios. Even in total absence of anthropogenic NOx emissions, 14–18 parks would still have a CL exceedance. Returning all parks to N deposition below CL by 2050 will require at least a 55% decrease in anthropogenic NH3 emissions relative to RCP-projected 2050 levels.

scholarly journals NITROGEN DEPOSITION ONTO THE UNITED STATES AND WESTERN EUROPE: SYNTHESIS OF OBSERVATIONS AND MODELS

2005 ◽  
Vol 15 (1) ◽  
pp. 38-57 ◽  
Author(s):  
Elisabeth A. Holland ◽  
Bobby H. Braswell ◽  
James Sulzman ◽  
Jean-Francois Lamarque
Keyword(s):  
United States ◽  
Nitrogen Deposition ◽  
Western Europe ◽  
The United States
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