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. 2024 Jan 2;3(1):pgad483. doi: 10.1093/pnasnexus/pgad483

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© The Author(s) 2024. Published by Oxford University Press on behalf of National Academy of Sciences.

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.

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Fig. 2. — Evaluation of simulated tropospheric NO₂ column concentrations with multiple satellite observations during between April–June 2019 and 2020. A) Observed NO₂ changes based on the average of four satellite instruments (S5P TROPOMI, Aura OMI, S-NPP OMPS, and NOAA-20 OMPS) with air mass factors or shape factors in the satellite products replaced by the model profiles. B) Model simulated NO₂ changes based on the average of resampled model data along each satellite track. C–H) NO₂ columns over urban (C and D), industrial/power plant (E and F), and O&G (G and H) source regions from satellite data (C, E, and G) and model estimates (D, F, and H) for 2019BAU (x-axis) and 2020 COVID scenario (2020COV, y-axis). Slope is calculated based on the orthogonal distance regression with 95% CI.