Increases in the formation of water soluble organic nitrogen during Asian dust storm episodes

doi:10.1016/j.atmosres.2021.105486

Atmospheric Research

Volume 253, May 2021, 105486

https://doi.org/10.1016/j.atmosres.2021.105486 Get rights and content

Highlights

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Understanding the origin of atmospheric sources of water soluble organic nitrogen at urban and coastal sites was carried out in China.
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The Asian dust storm was observed at the two sampling sites from April 25 to 28, 2012.
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WSON from dust source increased from ~10% during normal days to ~45% during dust storm days
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The largest sources contributing to WSON at the two sampling sites were secondary sources and fuel combustions

Abstract

There is increasing interest in understanding the origin of atmospheric sources of water soluble organic nitrogen (WSON) and its impact on anthropogenic nutrient pollution for terrestrial and marine ecosystem. This study aims to investigate the role of Asian dust storm on atmospheric water soluble organic nitrogen. PM_2.5 samples were collected simultaneously from April 1 to May 21, 2012 at the urban area of Zhangjiakou, Hebei province and the rural area of Tianjin near the coastal line, respectively. PM_2.5 mass and chemical compositions including ions, total metals, WSON, organic carbon and elemental carbon were adopted for source apportionment using receptor modeling. The sources of PM_2.5 mass at the two sampling sites were coal combustion, secondary source, industrial source, mobile source, dust source and biomass burning. The Asian dust storm was observed at the two sampling sites from April 25 to 28, 2012. Significant increases in WSON concentration from ~1.6 μg m⁻³ to 12 μg m⁻³ were found at the urban site (S1), and from ~1.3 μg m⁻³ to 18 μg m⁻³ at the coastal site (S2), respectively. Source apportionment results showed that the contributions to WSON from dust source increased from ~10% during normal days to ~45% during dust storm days, while the contributions from other sources kept relative stable (<5%) within normal days and dust storm days. The largest sources contributing to WSON at the two sampling sites were secondary sources and fuel combustions. Our study highlights the important role of Asian dust storm in the cycles of WSON in urban and coastal environments.

Graphical abstract

Section snippets

Introductions

Water soluble organic nitrogen (WSON) is an essential compound of reactive nitrogen species and plays an important role in the biogeochemical nitrogen cycle (Bhattarai et al., 2019; Liu et al. 2019a). WSON in reduced forms such as amine and urea could make significant contributions of the nutrient budgets to marine environment (Violaki and Mihalopoulos 2011; Neff et al. 2002). Milne and Zika (1993) estimated the inputs amounts of N flux in the form of amine to ocean was ~600 kg N yr⁻¹.

Sampling collections

As discussed above, the role of PM_2.5 in biogeochemical cycle of WOSN resulting from Asian dust storm was not explicit illustrated. Thus, PM_2.5 samples were collected from April1 to May 21, 2012 at Zhangjiakou, Hebei province (40^。75^，14”N, 114^。88^，30.0″E) and at Tianjin (40^。75^，1.8”N, 117^。40^，88.3″E), respectively. Zhangjikou is located in northern Hebei Province, which is close to semi-desert area in Inner Mongolia (Fig. S1B). The air quality in Zhangjiakou during spring season is prone to the

Impacts of dust storm on mass concentrations

The average mass concentration of PM_2.5 from April 1 to May 21, 2012 at urban site (S1) was 51 μg m⁻³, the minimum was 21 μg m⁻³ and the maximum was 120 μg m⁻³ (Table S3). The mass concentration of PM_2.5 from April 1 to May 21, 2012 at coastal site (S2) was observed to be in the range of 24–158 μg m⁻³, with a mean level of 54 μg m⁻³ (Table S3). No geographical differences in the average concentration of PM_2.5 mass concentration was observed within two sampling sites from April 1 to May 21, 2012.

Conclusions

This study collected PM_2.5 samples from April 1 to May 21, 2012 at the two sampling sites, which are located at the urban area of Zhangjiakou, Heibei province and the rural area of Tianjin near the coastal line, respectively. The Asian dust storm spread over the two sampling sites during the periods from April 25 to 28, 2012. Increases in PM_2.5 mass and chemical components including ions, metals, carbonaceous particles and WSON were observed at the two sampling sties. The levels of WSON

Declaration of Competing Interest

The authors declare that they have no known competing financial interestsor personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgement

This study was finically supported by National Science Foundation of China (No. 41175104, 41305110, 41475133). Dr. Qingyang Liu would like to thank the support from Scientific Research Foundation for High-Level Talents of Nanjing Forestry University (GXL2019034).