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Nitrogen isotope characteristics and source apportionment of atmospheric ammonium in urban cities during a haze event in Northern China Plain
https://orcid.org/0000-0001-8840-8454
Abstract Ammonium (NH4 +) is a well-known alkaline species for haze formation and possesses potential impacts on human health and biological diversity. To date, regional source apportionments of NH4 + have been poorly understood in Northern China Plain (NCP). In this study, daily PM2.5 samples were synchronously collected in eight cities over the NCP region. In addition to water-soluble ions, the nitrogen isotopic composition of NH4 + (δ15N–NH4 +) was also analyzed. The average concentrations of NH4 +, a targeted species, varied from 0.9 μg/m³ to 42.5 μg/m³. Note that the significant enhancements of NH4 + coincided with increasing PM2.5 masses, suggesting that NH4 + was one of the contributing species for haze formation. The δ15N–NH4 +averaged 12.4 ± 6.9‰ and the average δ15N–NH3 were further calculated to be −9.0 ± 6.7‰ over the NCP region. Both δ15N–NH4 + and δ15N–NH3 showed negative correlations with PM2.5 mass and there were no obvious differences among those 8 cities. Combining air-mass backward trajectories and quantifying contributions of potential sources, we pointed out that non-agricultural sources (fossil fuel related and NH3 slip) were dominant sources (totally contributed 42%–85%) not only on extreme haze phase but also on haze accumulation/dissipation phase in all 8 cities of NCP region in winter, the heating season in North China. However, the contribution of fossil fuel related source reduced to only 20%–35% while livestock breeding source rose to about 15%–32% and NH3 slip source kept contributing about 30% on the extreme haze phase. Thus, we considered that volatilization-related agricultural sources (especially livestock breeding) could discharge considerable NH3 to form SIA-led haze event in urban cities of the NCP region, even though non-agricultural sources were the foremost sources.
Graphical abstract Display Omitted
Highlights Regional transmission and source apportionments of atmospheric NHx during a haze event over the NCP were investigated. Non-agricultural sources were the dominant sources (42%–85%). Agricultural sources increased over 26% on extreme haze phase than others.
Nitrogen isotope characteristics and source apportionment of atmospheric ammonium in urban cities during a haze event in Northern China Plain
https://orcid.org/0000-0001-8840-8454
Abstract Ammonium (NH4 +) is a well-known alkaline species for haze formation and possesses potential impacts on human health and biological diversity. To date, regional source apportionments of NH4 + have been poorly understood in Northern China Plain (NCP). In this study, daily PM2.5 samples were synchronously collected in eight cities over the NCP region. In addition to water-soluble ions, the nitrogen isotopic composition of NH4 + (δ15N–NH4 +) was also analyzed. The average concentrations of NH4 +, a targeted species, varied from 0.9 μg/m³ to 42.5 μg/m³. Note that the significant enhancements of NH4 + coincided with increasing PM2.5 masses, suggesting that NH4 + was one of the contributing species for haze formation. The δ15N–NH4 +averaged 12.4 ± 6.9‰ and the average δ15N–NH3 were further calculated to be −9.0 ± 6.7‰ over the NCP region. Both δ15N–NH4 + and δ15N–NH3 showed negative correlations with PM2.5 mass and there were no obvious differences among those 8 cities. Combining air-mass backward trajectories and quantifying contributions of potential sources, we pointed out that non-agricultural sources (fossil fuel related and NH3 slip) were dominant sources (totally contributed 42%–85%) not only on extreme haze phase but also on haze accumulation/dissipation phase in all 8 cities of NCP region in winter, the heating season in North China. However, the contribution of fossil fuel related source reduced to only 20%–35% while livestock breeding source rose to about 15%–32% and NH3 slip source kept contributing about 30% on the extreme haze phase. Thus, we considered that volatilization-related agricultural sources (especially livestock breeding) could discharge considerable NH3 to form SIA-led haze event in urban cities of the NCP region, even though non-agricultural sources were the foremost sources.
Graphical abstract Display Omitted
Highlights Regional transmission and source apportionments of atmospheric NHx during a haze event over the NCP were investigated. Non-agricultural sources were the dominant sources (42%–85%). Agricultural sources increased over 26% on extreme haze phase than others.
Nitrogen isotope characteristics and source apportionment of atmospheric ammonium in urban cities during a haze event in Northern China Plain
https://orcid.org/0000-0001-8840-8454
Abstract Ammonium (NH4 +) is a well-known alkaline species for haze formation and possesses potential impacts on human health and biological diversity. To date, regional source apportionments of NH4 + have been poorly understood in Northern China Plain (NCP). In this study, daily PM2.5 samples were synchronously collected in eight cities over the NCP region. In addition to water-soluble ions, the nitrogen isotopic composition of NH4 + (δ15N–NH4 +) was also analyzed. The average concentrations of NH4 +, a targeted species, varied from 0.9 μg/m³ to 42.5 μg/m³. Note that the significant enhancements of NH4 + coincided with increasing PM2.5 masses, suggesting that NH4 + was one of the contributing species for haze formation. The δ15N–NH4 +averaged 12.4 ± 6.9‰ and the average δ15N–NH3 were further calculated to be −9.0 ± 6.7‰ over the NCP region. Both δ15N–NH4 + and δ15N–NH3 showed negative correlations with PM2.5 mass and there were no obvious differences among those 8 cities. Combining air-mass backward trajectories and quantifying contributions of potential sources, we pointed out that non-agricultural sources (fossil fuel related and NH3 slip) were dominant sources (totally contributed 42%–85%) not only on extreme haze phase but also on haze accumulation/dissipation phase in all 8 cities of NCP region in winter, the heating season in North China. However, the contribution of fossil fuel related source reduced to only 20%–35% while livestock breeding source rose to about 15%–32% and NH3 slip source kept contributing about 30% on the extreme haze phase. Thus, we considered that volatilization-related agricultural sources (especially livestock breeding) could discharge considerable NH3 to form SIA-led haze event in urban cities of the NCP region, even though non-agricultural sources were the foremost sources.
Graphical abstract Display Omitted
Highlights Regional transmission and source apportionments of atmospheric NHx during a haze event over the NCP were investigated. Non-agricultural sources were the dominant sources (42%–85%). Agricultural sources increased over 26% on extreme haze phase than others.
Nitrogen isotope characteristics and source apportionment of atmospheric ammonium in urban cities during a haze event in Northern China Plain
Xiang, Yan-Kun (author) / Dao, Xu (author) / Gao, Meng (author) / Lin, Yu-Chi (author) / Cao, Fang (author) / Yang, Xiao-Ying (author) / Zhang, Yan-Lin (author)
Atmospheric Environment ; 269
2021-10-17
Article (Journal)
Electronic Resource
English