Satellite-based NO2-GDP Index Quantifies the Emission Intensity of Economic Development

Economic activities release a significant amount of air pollution. Reducing the emission intensity of economic activities has been a key objective of the green transition. Some pollutants, such as NO2, have short lifetimes and stay mostly in place, so they can be used as tracers for local economic activity. Previous studies have been able to establish a relationship between satellite NO2 measurements and economic indicators, such as GDP. In this study, we use satellite NO2 products to analyze the relationship between NO2 and GDP measured in real terms, as well as trends in NO2 cost per unit GDP increase. First, we review three different satellite NO2 products, finding substantial differences among them. After comparing with ground observations, we conclude that the OMI NO2 product aligns most closely with NO2 trends observed by EPA AQS ground monitoring stations. We then use satellite NO2 products from 2005-2020 to establish a novel NO2/GDP index on two levels: the contiguous United States and globally. Through correlational and comparative analysis, we classify countries based on their NO2 emissions per unit of GDP and document trends in their NO2/GDP index over time. While most regions have a downward trend, countries such as Libya and Yemen have a positive trend, indicating increased emission intensity per unit GDP. On a national scale, states in the Northwest U.S. often have elevated index values, reaching as high as 17.89. These metrics provide a useful input in discussions of environmental policies and assessments of their global impact.