Abstract Intensified anthropogenic activities and high levels of energy consumption in cities have led to an increase in emissions of CO2 and air pollutants, impacting air quality and calling for better measures to monitor and reduce emissions. This study assesses the emission characteristics of cities in the Northern Hemisphere during two winter seasons from December 2018 to March 2020 using a combination of CO2 observations from the Orbiting Carbon Observatory-2 (OCO-2) along with CO and NO2 observations from the Sentinel-5 Precursor TROPOspheric Monitoring Instrument (S-5P TROPOMI). We calculate the estimates of urban enhancement concentrations of CO2, CO, and NO2 from anthropogenic emissions in cities. Moreover, using ratios of CO/CO2 and NO2/CO2 according to each city, we analyze the relationship between CO2 and air pollutants and find that cities show distinct emission patterns according to where they are located in different regions of the world. Our analysis shows that a positive relationship exists in the comparisons of CO/CO2 and NO2/CO2 ratios to city population and GDP. However, when cities in the Northern Hemisphere are divided into “developed” and “developing” regions, a difference in pattern is found where most developed cities show a smaller increase of both CO/CO2 and NO2/CO2 ratios with the increase of GDP, while developing cities show a larger increase of ratios per increase of GDP. Especially, developing cities facing rapid economic development like Mumbai and Tianjin show high emission ratios that almost match that of developed cities. The higher incline of increase in emission ratios in developing cities can be attributed to the low combustion efficiency of fossil fuels along with less stringent pollution control measures. This implies that pollution control measures are crucial for effective management of air quality degradation with economic advancement within these developing cities. The analysis also highlights the importance of urban geological features in cities such as that of Tehran and Milan which can trap air pollution under appropriate meteorological conditions. Despite the short period of analysis, our study demonstrates that satellite observations of CO2 and air pollutants together can provide clues about factors controlling the co-emission of air pollutants and carbon in cities and suggests that the application of the proposed methods with longer periods of observation will support coupled air quality and climate mitigation strategies.

中文翻译：

---

使用 CO2、CO 和 NO2 的星载观测评估北半球城市的排放特征

摘要 城市中人为活动的加剧和能源消耗的高水平导致二氧化碳和空气污染物的排放增加，影响了空气质量，并呼吁采取更好的措施来监测和减少排放。本研究结合轨道碳观测站 2 (OCO-2) 的 CO2 观测值以及 Sentinel- 的 CO 和 NO2 观测值，评估了北半球城市在 2018 年 12 月至 2020 年 3 月的两个冬季的排放特征。 5 前体对流层监测仪（S-5P TROPOMI）。我们计算了来自城市人为排放的 CO2、CO 和 NO2 城市增强浓度的估计值。此外，根据每个城市使用 CO/CO2 和 NO2/CO2 的比率，我们分析了二氧化碳和空气污染物之间的关系，发现城市根据它们在世界不同地区的位置表现出不同的排放模式。我们的分析表明，在 CO/CO2 和 NO2/CO2 比率与城市人口和 GDP 的比较中存在正相关关系。然而，当北半球的城市被划分为“发达”和“发展中”区域时，发现模式有所不同，大多数发达城市随着GDP的增加，CO/CO2和NO2/CO2比率的增加幅度较小，而发展中城市每增加GDP的比例增幅更大。尤其是孟买、天津等经济发展较快的发展中城市，其排放比高，几乎与发达城市不相上下。发展中城市排放率增加的趋势较高可归因于化石燃料的低燃烧效率以及不那么严格的污染控制措施。这意味着污染控制措施对于有效管理这些发展中城市中经济进步的空气质量退化至关重要。分析还强调了德黑兰和米兰等城市的城市地质特征的重要性，它们可以在适当的气象条件下捕获空气污染。尽管分析时间很短，