COVID-19 impacts on anthropogenic NO x emissions in China, the contiguous U.S., and Europe: insights from joint TROPOMI and surface NO ₂ data assimilation
- 1State Key Laboratory of Severe Weather Meteorological Science and Technology (LaSw) & Monitoring and Assessment Center for Greenhouse Gases and Carbon Neutrality of CMA Chinese Academy of Meteorological Sciences
- 2Fudan University
- 3Laboratory of Climate Change Mitigation and Carbon Neutrality Henan University
Abstract
This study integrates satellite and surface NO ₂ measurements through the ensemble square root filter and the GEOS‐Chem model to estimate anthropogenic NO x emissions for China, the contiguous U.S., and Europe over 2019–2020, and further examines how the COVID‐19 pandemic altered emission patterns and sectoral contributions. Our results show that in 2020, anthropogenic NO x emissions were 19.20 ± 5.87 Tg in China, 8.96 ± 2.90 Tg in the contiguous U.S., and 10.56 ± 2.95 Tg in Europe. Compared with 2019, emissions decreased by about 5.38% in China, 8.94% in the contiguous U.S., and 15.38% in Europe. In China, emission reductions came from transportation, power plants, and industry. In contrast, reductions in the contiguous U.S. and Europe were almost entirely from transportation. These differences reflect the fundamental gap in energy structure and industry models between developed and developing economies. During the first wave of the pandemic, emissions fell sharply compared to the same period in 2019. The decreases were 18.04% in China, 10.56% in the contiguous U.S., and 21.74% in Europe. Large spatial variations were observed within each region. This work provides observation-based evidence of NO x emission changes across major world regions during COVID 19. It highlights how emissions can behave differently under sudden public health crises. The findings are useful for checking bottom-up emission inventories, assessing extreme events’ impacts on air quality, and designing better emission reduction policies.
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BibTeX
@article{wu2026covid19,
title = {{COVID-19 impacts on anthropogenic NO x emissions in China, the contiguous U.S., and Europe: insights from joint TROPOMI and surface NO ₂ data assimilation}},
author = {Chongyuan Wu and Xiaoye Zhang and Lifeng Guo and Junting Zhong and Deying Wang and Jiaying Li and Bingyi Wu and Changhong Miao},
journal = {Environmental Research Letters},
year = {2026},
month = oct,
doi = {10.1088/1748-9326/aeaf6b},
url = {https://iopscience.iop.org/article/10.1088/1748-9326/aeaf6b},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - COVID-19 impacts on anthropogenic NO x emissions in China, the contiguous U.S., and Europe: insights from joint TROPOMI and surface NO ₂ data assimilation
AU - Chongyuan Wu
AU - Xiaoye Zhang
AU - Lifeng Guo
AU - Junting Zhong
AU - Deying Wang
AU - Jiaying Li
AU - Bingyi Wu
AU - Changhong Miao
PY - 2026
DA - 2026/10/12
JO - Environmental Research Letters
DO - 10.1088/1748-9326/aeaf6b
UR - https://iopscience.iop.org/article/10.1088/1748-9326/aeaf6b
AB - This study integrates satellite and surface NO ₂ measurements through the ensemble square root filter and the GEOS‐Chem model to estimate anthropogenic NO x emissions for China, the contiguous U.S., and Europe over 2019–2020, and further examines how the COVID‐19 pandemic altered emission patterns and sectoral contributions. Our results show that in 2020, anthropogenic NO x emissions were 19.20 ± 5.87 Tg in China, 8.96 ± 2.90 Tg in the contiguous U.S., and 10.56 ± 2.95 Tg in Europe. Compared with 2019, emissions decreased by about 5.38% in China, 8.94% in the contiguous U.S., and 15.38% in Europe. In China, emission reductions came from transportation, power plants, and industry. In contrast, reductions in the contiguous U.S. and Europe were almost entirely from transportation. These differences reflect the fundamental gap in energy structure and industry models between developed and developing economies. During the first wave of the pandemic, emissions fell sharply compared to the same period in 2019. The decreases were 18.04% in China, 10.56% in the contiguous U.S., and 21.74% in Europe. Large spatial variations were observed within each region. This work provides observation-based evidence of NO x emission changes across major world regions during COVID 19. It highlights how emissions can behave differently under sudden public health crises. The findings are useful for checking bottom-up emission inventories, assessing extreme events’ impacts on air quality, and designing better emission reduction policies.
SN - 1748-9326
ER -