Anthropogenic imprints on nitrogen and oxygen isotopic composition of precipitation nitrate in a nitrogen-polluted city in southern China
Nitric acid (HNO<sub>3</sub>) or nitrate (NO<sub>3</sub><sup>&minus;</sup>) is the dominant sink for reactive nitrogen oxides (NO<sub>x</sub> = NO + NO<sub>2</...
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| Format: | Article |
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Copernicus Publications
2011-02-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | http://www.atmos-chem-phys.net/11/1313/2011/acp-11-1313-2011.pdf |
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| author | Y. T. Fang K. Koba X. M. Wang D. Z. Wen J. Li Y. Takebayashi X. Y. Liu M. Yoh |
| author_facet | Y. T. Fang K. Koba X. M. Wang D. Z. Wen J. Li Y. Takebayashi X. Y. Liu M. Yoh |
| author_sort | Y. T. Fang |
| collection | DOAJ |
| description | Nitric acid (HNO<sub>3</sub>) or nitrate (NO<sub>3</sub><sup>&minus;</sup>) is the dominant sink for reactive nitrogen oxides (NO<sub>x</sub> = NO + NO<sub>2</sub>) in the atmosphere. In many Chinese cities, HNO<sub>3</sub> is becoming a significant contributor to acid deposition. In the present study, we measured nitrogen (N) and oxygen (O) isotopic composition of NO<sub>3</sub><sup>&minus;</sup> in 113 precipitation samples collected from Guangzhou City in southern China over a two-year period (2008 and 2009). We attempted to better understand the spatial and seasonal variability of atmospheric NO<sub>x</sub> sources and the NO<sub>3</sub><sup>&minus;</sup> formation pathways in this N-polluted city in the Pearl River Delta region. The &delta;<sup>15</sup>N values of NO<sub>3</sub><sup>&minus;</sup> (versus air N<sub>2</sub>) ranged from −4.9 to +10.1&permil;, and averaged +3.9&permil; in 2008 and +3.3&permil; in 2009. Positive &delta;<sup>15</sup>N values were observed throughout the year, indicating the anthropogenic contribution of NO<sub>x</sub> emissions, particularly from coal combustion. Different seasonal patterns of &delta;<sup>15</sup>N-NO<sub>3</sub><sup>&minus;</sup> were observed between 2008 and 2009, which might reflect different human activities associated with the global financial crisis and the intensive preparations for the 16th Asian Games. Nitrate &delta;<sup>18</sup>O values (versus Vienna Standard Mean Ocean Water) varied from +33.4 to +86.5&permil; (average +65.0&permil; and +67.0&permil; in 2008 and 2009, respectively), a range being lower than those reported for high latitude and polar areas. Sixteen percent of &delta;<sup>18</sup>O values was observed lower than the expected minimum of +55&permil; at our study site. This was likely caused by the reaction of NO with peroxy radicals; peroxy radicals can compete with O<sub>3</sub> to convert NO to NO<sub>2</sub>, thereby donate O atoms with much lower &delta;<sup>18</sup>O value than that of O<sub>3</sub> to atmospheric NO<sub>3</sub><sup>&minus;</sup>. Our results highlight that the influence of human activities on atmospheric chemistry can be recorded by the N and O isotopic composition of atmospheric NO<sub>3</sub><sup>&minus;</sup> in a N-polluted city. |
| first_indexed | 2024-12-10T18:45:06Z |
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| publishDate | 2011-02-01 |
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| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-ff4e878f8dac4aa49de8bacecfdd084c2022-12-22T01:37:32ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242011-02-011131313132510.5194/acp-11-1313-2011Anthropogenic imprints on nitrogen and oxygen isotopic composition of precipitation nitrate in a nitrogen-polluted city in southern ChinaY. T. FangK. KobaX. M. WangD. Z. WenJ. LiY. TakebayashiX. Y. LiuM. YohNitric acid (HNO<sub>3</sub>) or nitrate (NO<sub>3</sub><sup>&minus;</sup>) is the dominant sink for reactive nitrogen oxides (NO<sub>x</sub> = NO + NO<sub>2</sub>) in the atmosphere. In many Chinese cities, HNO<sub>3</sub> is becoming a significant contributor to acid deposition. In the present study, we measured nitrogen (N) and oxygen (O) isotopic composition of NO<sub>3</sub><sup>&minus;</sup> in 113 precipitation samples collected from Guangzhou City in southern China over a two-year period (2008 and 2009). We attempted to better understand the spatial and seasonal variability of atmospheric NO<sub>x</sub> sources and the NO<sub>3</sub><sup>&minus;</sup> formation pathways in this N-polluted city in the Pearl River Delta region. The &delta;<sup>15</sup>N values of NO<sub>3</sub><sup>&minus;</sup> (versus air N<sub>2</sub>) ranged from −4.9 to +10.1&permil;, and averaged +3.9&permil; in 2008 and +3.3&permil; in 2009. Positive &delta;<sup>15</sup>N values were observed throughout the year, indicating the anthropogenic contribution of NO<sub>x</sub> emissions, particularly from coal combustion. Different seasonal patterns of &delta;<sup>15</sup>N-NO<sub>3</sub><sup>&minus;</sup> were observed between 2008 and 2009, which might reflect different human activities associated with the global financial crisis and the intensive preparations for the 16th Asian Games. Nitrate &delta;<sup>18</sup>O values (versus Vienna Standard Mean Ocean Water) varied from +33.4 to +86.5&permil; (average +65.0&permil; and +67.0&permil; in 2008 and 2009, respectively), a range being lower than those reported for high latitude and polar areas. Sixteen percent of &delta;<sup>18</sup>O values was observed lower than the expected minimum of +55&permil; at our study site. This was likely caused by the reaction of NO with peroxy radicals; peroxy radicals can compete with O<sub>3</sub> to convert NO to NO<sub>2</sub>, thereby donate O atoms with much lower &delta;<sup>18</sup>O value than that of O<sub>3</sub> to atmospheric NO<sub>3</sub><sup>&minus;</sup>. Our results highlight that the influence of human activities on atmospheric chemistry can be recorded by the N and O isotopic composition of atmospheric NO<sub>3</sub><sup>&minus;</sup> in a N-polluted city.http://www.atmos-chem-phys.net/11/1313/2011/acp-11-1313-2011.pdf |
| spellingShingle | Y. T. Fang K. Koba X. M. Wang D. Z. Wen J. Li Y. Takebayashi X. Y. Liu M. Yoh Anthropogenic imprints on nitrogen and oxygen isotopic composition of precipitation nitrate in a nitrogen-polluted city in southern China Atmospheric Chemistry and Physics |
| title | Anthropogenic imprints on nitrogen and oxygen isotopic composition of precipitation nitrate in a nitrogen-polluted city in southern China |
| title_full | Anthropogenic imprints on nitrogen and oxygen isotopic composition of precipitation nitrate in a nitrogen-polluted city in southern China |
| title_fullStr | Anthropogenic imprints on nitrogen and oxygen isotopic composition of precipitation nitrate in a nitrogen-polluted city in southern China |
| title_full_unstemmed | Anthropogenic imprints on nitrogen and oxygen isotopic composition of precipitation nitrate in a nitrogen-polluted city in southern China |
| title_short | Anthropogenic imprints on nitrogen and oxygen isotopic composition of precipitation nitrate in a nitrogen-polluted city in southern China |
| title_sort | anthropogenic imprints on nitrogen and oxygen isotopic composition of precipitation nitrate in a nitrogen polluted city in southern china |
| url | http://www.atmos-chem-phys.net/11/1313/2011/acp-11-1313-2011.pdf |
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