For decades, rising prosperity meant more cars, more factories, and dirtier air. New satellite evidence now shows that link is breaking. Researchers found that nearly 80 percent of the world's largest urban areas are getting richer and breathing cleaner air at the same time.
A satellite named Sentinel-5P tracked 2,475 cities over five years
Scientists at Norway's NILU research institute used data from the European Space Agency's Copernicus Sentinel-5P satellite to measure nitrogen dioxide levels in 2,475 major cities around the world. Nitrogen dioxide is a harmful pollutant produced mainly by burning fossil fuels in vehicles, power plants, and factories. It can irritate the lungs, worsen asthma, increase heart and lung problems, and contribute to premature deaths. It also helps form smog, ground-level ozone, and fine particulate matter, and it damages ecosystems through acid rain.
The team compared the satellite readings, collected between January 2019 and December 2024, with local gross domestic product per capita. Because Sentinel-5P provides consistent global coverage, researchers could track changes across thousands of cities at once.
Almost 2,000 cities are now cleaner and richer
The study, published in the journal Nature Cities, found that 1,980 of the 2,475 cities studied have implemented green policies that allowed them to reduce their dependence on fossil fuels while still growing their economies. That means cleaner air and higher prosperity are no longer a trade-off in most major urban centers.
The trend is especially strong in China, which accounted for 719 of the cities that achieved both cleaner air and economic growth. The findings suggest that the old pattern of growth at the expense of public health is shifting in many parts of the world.
What this means for people living in cities
For residents of these urban areas, the change is directly measurable. Lower nitrogen dioxide levels mean fewer asthma attacks, less respiratory disease, and reduced risk of heart and lung problems. The pollutant also contributes to climate change indirectly and reduces crop yields through nitrogen deposition. So cleaner air has benefits that extend beyond human health to food production and ecosystems.
The satellite data shows that economic growth and environmental quality can move in the same direction. The research does not claim this is happening everywhere, but it documents a widespread shift that was not visible before Sentinel-5P began its global monitoring.
