When measuring pollution by PM2.5 levels, Zürich ranks outstandingly as the city with the cleanest air in the world. But once looked at according to levels of NO2, the story turns on its head.

Tracking air pollution and CO2 emissions in 13,189 urban areas worldwide using large geospatial datasets. Communications Earth & Environment, 2025; 6 (1) DOI: 10.1038/s43247-025-02270-9 ...

To assess each city's air quality, the team began by creating a list of all the cities in the U.S. and Europe. Next, the team input the list into the Google Keyword Planner and combined each city ...

For Embargo Release: May 7, 2025 at 5 am ET USA Media Contact: Katelyn Deckelbaum, [email protected] New Study Tracks Air Pollution and CO₂ Emissions Across Thousands of Cities Worldwide ...