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Nitrogen isotopes as indicators of NOx source contributions to atmospheric nitrate deposition across the midwestern and northeastern United States

Environmental Science and Technology

By:
, , , , , , , and
DOI: 10.1021/es070898t

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Abstract

Global inputs of NOx are dominated by fossil fuel combustion from both stationary and vehicular sources and far exceed natural NOx sources. However, elucidating NOx sources to any given location remains a difficult challenge, despite the need for this information to develop sound regulatory and mitigation strategies. We present results from a regional-scale study of nitrogen isotopes (??15N) in wet nitrate deposition across 33 sites in the midwestern and northeastern U.S. We demonstrate that spatial variations in ??15N are strongly correlated with NOx emissions from surrounding stationary sources and additionally that ??15N is more strongly correlated with surrounding stationary source NOx emissions than pH, SO 42-, or NO3- concentrations. Although emission inventories indicate that vehicle emissions are the dominant NOx source in the eastern U.S., our results suggest that wet NO 3- deposition at sites in this study is strongly associated with NOx emissions from stationary sources. This suggests that large areas of the landscape potentially receive atmospheric NOy deposition inputs in excess of what one would infer from existing monitoring data alone. Moreover, we determined that spatial patterns in ??15N values are a robust indicator of stationary NOx contributions to wet NO3- deposition and hence a valuable complement to existing tools for assessing relationships between NO 3- deposition, regional emission inventories, and for evaluating progress toward NOx reduction goals. ?? 2007 American Chemical Society.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Nitrogen isotopes as indicators of NOx source contributions to atmospheric nitrate deposition across the midwestern and northeastern United States
Series title:
Environmental Science and Technology
DOI:
10.1021/es070898t
Volume
41
Issue:
22
Year Published:
2007
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Environmental Science and Technology
First page:
7661
Last page:
7667
Number of Pages:
7