By using space-based measurements of the column-averaged dry air mole fraction of carbon dioxide (XCO
2) from the Orbiting Carbon Observatory-2 (OCO-2) and CO and NO
2 from the Tropospheric Monitoring Instrument (TROPOMI), this study investigates the seasonal variation in the characteristics
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By using space-based measurements of the column-averaged dry air mole fraction of carbon dioxide (XCO
2) from the Orbiting Carbon Observatory-2 (OCO-2) and CO and NO
2 from the Tropospheric Monitoring Instrument (TROPOMI), this study investigates the seasonal variation in the characteristics of CO
2, CO, and NO
2 across major states in the United States. Beyond correlating these trends with natural factors, significant emphasis is placed on human activities, including heating demands, energy usage, and the impacts of the COVID-19 pandemic. Concentration enhancements in observations influenced by anthropogenic emissions from urban regions relative to background values are calculated to estimate gas emissions. Our investigation reveals a strong correlation between NO
2 and CO
2 emissions, as evidenced by a correlation coefficient (r) of 0.75. Furthermore, we observe a correlation of 0.48 between CO
2 and CO emissions and a weaker correlation of 0.37 between CO and NO
2 emissions. Notably, we identify the NO
2 concentration as a reliable indicator of CO
2 emission levels, in which a 1% increase in NO
2 concentration corresponds to a 0.8194% (±0.0942%) rise in annual mean CO
2 emissions. Enhancement ratios among NO
2, CO, and XCO
2 are also calculated, uncovering that high ΔNO
2: ΔXCO
2 ratios often signify outdated industrial structures and production technologies, while low ΔCO: ΔXCO
2 ratios are linked to states that utilize clean energy sources. This approach offers a deeper understanding of the effect of human activities on atmospheric gas concentrations, paving the way for more effective environmental monitoring and policy-making.
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