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Spatiotemporal variations of atmospheric nitrogen deposition in China during 2008–2020
https://orcid.org/0000-0002-1042-5649
https://orcid.org/0000-0002-4111-6689
https://orcid.org/0000-0001-8250-0567
https://orcid.org/0000-0001-7783-5725
Abstract In recent decades, China has been a hotspot for reactive nitrogen (N) deposition due to intensive fossil fuel burning and increased agricultural activities. The Chinese government has implemented active measures to protect air quality and reduce N deposition. In this study, we combined monthly measurements of monitoring sites and satellite data to construct random forest (RF) models for the estimation of monthly N deposition in China during 2008–2020. This provides N deposition estimation in latest years and has a finer temporal resolution. The RF models can address more complicated relationships between variables and performed well in estimating N deposition compared to the measurements with average correlation coefficients of 0.79 and 0.77 for dry and wet N deposition, respectively. We found that mean annual total N deposition was 22.0 ± 0.8 kg N ha−1 yr−1 during 2008–2020, which accounted for 64% (±4%) of reactive N emissions in China. Although the total N deposition was high, it has stabilized and decreased slightly over the past decade, with dry and wet N deposition contributing equally to the total N deposition. NHx deposition (FNHx) still slowly increased (0.09 kg N ha−1 yr−2) during 2015–2020, when N fertilizer application and livestock started to decrease. This is due to the rapid decline in NOx and SO2 emissions during the same period. Our results provide a new perspective on the spatiotemporal variations in the total N deposition in China. It is necessary to optimize other emission reduction strategies to mitigate air pollution and N deposition.
Highlights The reactive nitrogen (N) deposition in China from 2008 to 2020 was estimated using random forest models. N deposition in China accounted for 64% (±4%) of the atmospheric N emissions, with equal contributions from dry and wet N deposition. Reducing NOx and SO2 emissions along was not enough to decrease total N deposition.
Spatiotemporal variations of atmospheric nitrogen deposition in China during 2008–2020
https://orcid.org/0000-0002-1042-5649
https://orcid.org/0000-0002-4111-6689
https://orcid.org/0000-0001-8250-0567
https://orcid.org/0000-0001-7783-5725
Abstract In recent decades, China has been a hotspot for reactive nitrogen (N) deposition due to intensive fossil fuel burning and increased agricultural activities. The Chinese government has implemented active measures to protect air quality and reduce N deposition. In this study, we combined monthly measurements of monitoring sites and satellite data to construct random forest (RF) models for the estimation of monthly N deposition in China during 2008–2020. This provides N deposition estimation in latest years and has a finer temporal resolution. The RF models can address more complicated relationships between variables and performed well in estimating N deposition compared to the measurements with average correlation coefficients of 0.79 and 0.77 for dry and wet N deposition, respectively. We found that mean annual total N deposition was 22.0 ± 0.8 kg N ha−1 yr−1 during 2008–2020, which accounted for 64% (±4%) of reactive N emissions in China. Although the total N deposition was high, it has stabilized and decreased slightly over the past decade, with dry and wet N deposition contributing equally to the total N deposition. NHx deposition (FNHx) still slowly increased (0.09 kg N ha−1 yr−2) during 2015–2020, when N fertilizer application and livestock started to decrease. This is due to the rapid decline in NOx and SO2 emissions during the same period. Our results provide a new perspective on the spatiotemporal variations in the total N deposition in China. It is necessary to optimize other emission reduction strategies to mitigate air pollution and N deposition.
Highlights The reactive nitrogen (N) deposition in China from 2008 to 2020 was estimated using random forest models. N deposition in China accounted for 64% (±4%) of the atmospheric N emissions, with equal contributions from dry and wet N deposition. Reducing NOx and SO2 emissions along was not enough to decrease total N deposition.
Spatiotemporal variations of atmospheric nitrogen deposition in China during 2008–2020
https://orcid.org/0000-0002-1042-5649
https://orcid.org/0000-0002-4111-6689
https://orcid.org/0000-0001-8250-0567
https://orcid.org/0000-0001-7783-5725
Abstract In recent decades, China has been a hotspot for reactive nitrogen (N) deposition due to intensive fossil fuel burning and increased agricultural activities. The Chinese government has implemented active measures to protect air quality and reduce N deposition. In this study, we combined monthly measurements of monitoring sites and satellite data to construct random forest (RF) models for the estimation of monthly N deposition in China during 2008–2020. This provides N deposition estimation in latest years and has a finer temporal resolution. The RF models can address more complicated relationships between variables and performed well in estimating N deposition compared to the measurements with average correlation coefficients of 0.79 and 0.77 for dry and wet N deposition, respectively. We found that mean annual total N deposition was 22.0 ± 0.8 kg N ha−1 yr−1 during 2008–2020, which accounted for 64% (±4%) of reactive N emissions in China. Although the total N deposition was high, it has stabilized and decreased slightly over the past decade, with dry and wet N deposition contributing equally to the total N deposition. NHx deposition (FNHx) still slowly increased (0.09 kg N ha−1 yr−2) during 2015–2020, when N fertilizer application and livestock started to decrease. This is due to the rapid decline in NOx and SO2 emissions during the same period. Our results provide a new perspective on the spatiotemporal variations in the total N deposition in China. It is necessary to optimize other emission reduction strategies to mitigate air pollution and N deposition.
Highlights The reactive nitrogen (N) deposition in China from 2008 to 2020 was estimated using random forest models. N deposition in China accounted for 64% (±4%) of the atmospheric N emissions, with equal contributions from dry and wet N deposition. Reducing NOx and SO2 emissions along was not enough to decrease total N deposition.
Spatiotemporal variations of atmospheric nitrogen deposition in China during 2008–2020
Chen, Shiliang (author) / Chen, Bin (author) / Wang, Shaoqiang (author) / Sun, Leigang (author) / Shi, Hao (author) / Liu, Zhenhai (author) / Wang, Qinyi (author) / Li, Hui (author) / Zhu, Tongtong (author) / Li, Donghui (author)
Atmospheric Environment ; 315
2023-09-30
Article (Journal)
Electronic Resource
English
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