气候变化领域集成服务门户(CCPortal): Systematic low bias of passive samplers in characterizing nitrogen isotopic composition of atmospheric ammonia

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DOI	10.1016/j.atmosres.2020.105018
	Systematic low bias of passive samplers in characterizing nitrogen isotopic composition of atmospheric ammonia
	Pan Y.; Gu M.; Song L.; Tian S.; Wu D.; Walters W.W.; Yu X.; Lü X.; Ni X.; Wang Y.; Cao J.; Liu X.; Fang Y.; Wang Y.
发表日期	2020
ISSN	0169-8095
卷号	243
英文摘要	Identifying the sources of increased ammonia (NH3) in the atmosphere has important implications for air quality, ecosystems, and climate. While analysis of the nitrogen isotopic composition (δ15N) can aid in the apportionment of NH3 emission sources, the widely-used passive collection methods have not been verified for their ability to accurately characterize δ15N-NH3. In this study, three types of passive samplers (ALPHA, Analyst, and Radiello) were employed and collocated with a denuder based active sampler (DELTA, serves as a reference method) to compare and contrast their ability in collecting atmospheric NH3 for subsequent concentration and δ15N-NH3 analysis in urban Beijing during the summer of 2018. The results showed that NH3 concentrations determined using passive collection samplers that included ALPHA (n = 11), Analyst (n = 12), and Radiello (n = 7) samplers were 13.4%, 14.4%, and 27.5% lower than that of the active sampler (n = 12), respectively. The low NH3 concentration bias in the passive collection samplers was suggested to be the result of inaccurate effective sampling rates due to incorrect mass transfer correction factors for the environmental conditions of this study. The δ15N-NH3 values did not show significant differences between passive samplers, with weekly means of −31.0 ± 1.0‰ (n = 4), −28.4 ± 5.5‰ (n = 4), and −29.1 ± 0.9‰ (n = 4) for the ALPHA, Analyst, and Radiello, respectively. Notably, the overall mean δ15N-NH3 values collected by these passive samplers (−29.5 ± 3.2‰, n = 12) was significantly lower than that of the active sampler (−14.1 ± 1.6‰, n = 4), with a difference of 15.4 ± 3.5‰. The large underestimation of δ15N-NH3 values by passive samplers can be explained by the diffusive isotope fractionation of NH3 isotopologues, which is driven by relative mass differences of 14NH3 and 15NH3. Overall, these findings highlight a potential low bias in NH3 concentrations and a substantial uncertainty in previous source interpretation using δ15N-NH3 as previous studies have almost exclusively characterized δ15N-NH3 using passive samplers. We suggest that the denuder-based active sampler should be used in the future for characterizing δ15N-NH3 whether at the source or in an atmospheric environment with mixed sources. This work also has important implications for characterizing δ15N of other gaseous nitrogen compounds. © 2020 Elsevier B.V.
关键词	Air quality Isotopes Mass transfer Atmospheric ammonia Atmospheric environment Collection methods Correction factors Environmental conditions Isotope fractionation Nitrogen isotopic Reference method Ammonia air quality ammonia atmospheric chemistry concentration (composition)error correction isotopic composition mass transfer nitrogen isotope pollution monitoring source apportionment Beijing [Beijing (ADS)]Beijing [China]China
语种	英语
来源机构	Atmospheric Research
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/132423
推荐引用方式 GB/T 7714	Pan Y.,Gu M.,Song L.,et al. Systematic low bias of passive samplers in characterizing nitrogen isotopic composition of atmospheric ammonia[J]. Atmospheric Research,2020,243.
APA	Pan Y..,Gu M..,Song L..,Tian S..,Wu D..,...&Wang Y..(2020).Systematic low bias of passive samplers in characterizing nitrogen isotopic composition of atmospheric ammonia.,243.
MLA	Pan Y.,et al."Systematic low bias of passive samplers in characterizing nitrogen isotopic composition of atmospheric ammonia".243(2020).