Increasing trends in wintertime particulate sulfate and nitrate ion concentrations in the Great Plains of the United States (2000–2010)

Hand, Jenny L.; Gebhart, Kristi A.; Schichtel, B. A.; Malm, William C.

doi:10.1016/j.atmosenv.2012.03.050

Cited by 29 publications

(47 citation statements)

References 11 publications

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“…We also observed that increased sulfate concentrations in December did not coincide with an increase in SO 2 emissions. Several possible causes have been speculated, 11 such as impacts from oil and gas development, transport from oil sand regions in Canada, meteorological influences, or a likely combination of all. In both the spring and winter cases, the local and regional SO 2 emissions could not account for the sulfate concentration behavior.…”

Section: Resultsmentioning

confidence: 99%

Widespread reductions in sulfate across the United States since the early 1990s

Hand¹,

Schichtel²,

Malm³

et al. 2013

AIP Conference Proceedings

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Particulate sulfate ion concentrations were examined across the United States at remote/rural sites from the Interagency Monitoring of Protected Visual Environments (IMPROVE) and urban sites from the Environmental Protection Agency's (EPA) Chemical Speciation Network (CSN) from the early 1990s through 2010. Temporal trends in sulfate concentrations revealed widespread reductions of sulfate at both urban and rural sites on an annual basis, with higher rates of decrease in the eastern United States relative to the West. In the western United States sulfate concentrations have not decreased as strongly and in some regions and seasons actually increased. Similar temporal trends in measured power plant SO 2 emissions suggested a near linear relationship between emissions and sulfate concentrations that was strongest in the eastern United States. This work suggests that regulating SO 2 emissions has been extremely successful in lowering sulfate concentrations in the East, however, impacts from unregulated sources and potentially international contributions appear to be affecting sulfate concentrations in the West and may become increasingly important, especially as regulated sources of SO 2 emissions continue to decrease.

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Section: Resultsmentioning

confidence: 99%

Widespread reductions in sulfate across the United States since the early 1990s

Hand¹,

Schichtel²,

Malm³

et al. 2013

AIP Conference Proceedings

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“…We showed that

([], {SO}_{4}^{2 -})

(DJF) declines more sharply in response to SO 2 emission reductions in the absence of NH 3 emissions, as cloud pH would remain too low to allow significant oxidation of SO 2 by O 3 . Thus, anthropogenic NH 3 emissions, which are expected to continue to increase in the future, contribute not only directly (via NH 4 NO 3 ) [ Pinder et al , ; Heald et al , ; Paulot and Jacob , ] but also indirectly (via increased

{SO}_{4}^{2 -}

production) to challenges in improving U.S. winter air quality [ Hand et al , ].…”

Section: Discussionmentioning

confidence: 99%

Contrasting seasonal responses of sulfate aerosols to declining SO₂ emissions in the Eastern U.S.: Implications for the efficacy of SO₂ emission controls

Paulot

Fan

Horowitz

2017

Geophysical Research Letters

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Stringent controls have reduced U.S. SO2 emissions by over 60% since the late 1990s. These controls have been more effective at reducing surface []SO42− in summer (June, July, and August) than in winter (December, January, and February (DJF)), a seasonal contrast that is not robustly captured by Climate Model Intercomparison Project 5 global models. We use the Geophysical Fluid Dynamics Laboratory AM3 chemistry‐climate model to show that oxidant limitation during winter causes []SO42− (DJF) to be sensitive to primary SO42− emissions, in‐cloud titration of H2O2, and in‐cloud oxidation by O3. The observed contrast in the seasonal response of []SO42− to decreasing SO2 emissions is best explained by the O3 reaction, whose rate coefficient has increased over the past decades as a result of increasing NH3 emissions and decreasing SO2 emissions, both of which lower cloud water acidity. The fraction of SO2 oxidized to SO42− is projected to keep increasing in future decades, delaying improvements in wintertime air quality.

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“…In North America's northern Great Plains (NGP), rapid development of fossil fuel extraction and increasing agricultural intensity threaten to increase N emissions and deposition in this area of historically clean air (Hand et al. , Ellis et al. ).…”

Section: Introductionmentioning

confidence: 99%

“…Despite strides made in reducing some emissions sources, N emissions from agriculture and fossil fuel combustion continue to rise in some regions (Galloway et al 2008). In North America's northern Great Plains (NGP), rapid development of fossil fuel extraction and increasing agricultural intensity threaten to increase N emissions and deposition in this area of historically clean air (Hand et al 2012, Ellis et al 2013. The soils in most of the region buffer the dominant grasslands from detrimental effects of acid deposition associated with sulfur and N because of their relatively high base cation saturation (Fenn et al 2003).…”

Section: Introductionmentioning

confidence: 99%

Experimentally derived nitrogen critical loads for northern Great Plains vegetation

Symstad

Smith

Newton

et al. 2019

Ecological Applications

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The critical load concept facilitates communication between scientists and policy makers and land managers by translating the complex effects of air pollution on ecosystems into unambiguous numbers that can be used to inform air quality targets. Anthropogenic atmospheric nitrogen (N) deposition adversely affects a variety of ecosystems, but the information used to derive critical loads for North American ecosystems is sparse and often based on experiments investigating N loads substantially higher than current or expected atmospheric deposition. In a 4‐yr field experiment in the northern Great Plains (NGP) of North America, where current N deposition levels range from ~3 to 9 kg N·ha−1·yr−1, we added 12 levels of N, from 2.5 to 100 kg N·ha−1·yr−1, to three sites spanning a range of soil fertility and productivity. Our results suggest a conservative critical load of 4–6 kg N·ha−1·yr−1 for the most sensitive vegetation type we investigated, badlands sparse vegetation, a community that supports plant species adapted to low fertility conditions, where N addition at this rate increased productivity and litter load. In contrast, for the two more productive vegetation types characteristic of most NGP grasslands, a critical load of 6–10 kg N·ha−1·yr−1 was identified. Here, N addition at this level altered plant tissue chemistry and increased nonnative species. These critical loads are below the currently suggested range of 10–25 kg N·ha−1·yr−1 for NGP vegetation and within the range of current or near‐future deposition, suggesting that N deposition may already be inducing fundamental changes in NGP ecosystems.

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Increasing trends in wintertime particulate sulfate and nitrate ion concentrations in the Great Plains of the United States (2000–2010)

Cited by 29 publications

References 11 publications

Widespread reductions in sulfate across the United States since the early 1990s

Widespread reductions in sulfate across the United States since the early 1990s

Contrasting seasonal responses of sulfate aerosols to declining SO₂ emissions in the Eastern U.S.: Implications for the efficacy of SO₂ emission controls

Experimentally derived nitrogen critical loads for northern Great Plains vegetation

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Increasing trends in wintertime particulate sulfate and nitrate ion concentrations in the Great Plains of the United States (2000–2010)

Cited by 29 publications

References 11 publications

Widespread reductions in sulfate across the United States since the early 1990s

Widespread reductions in sulfate across the United States since the early 1990s

Contrasting seasonal responses of sulfate aerosols to declining SO2 emissions in the Eastern U.S.: Implications for the efficacy of SO2 emission controls

Experimentally derived nitrogen critical loads for northern Great Plains vegetation

Contact Info

Product

Resources

About

Contrasting seasonal responses of sulfate aerosols to declining SO₂ emissions in the Eastern U.S.: Implications for the efficacy of SO₂ emission controls