WASHINGTON — Air pollution increased in dozens of cities after the United States stopped publishing independent air-quality readings from embassies and consulates, according to a study published this week in the journal PNAS.
Researchers estimated local pollution rose about 24% to 33% in the months after the Trump administration halted the long-running monitoring program in March 2025, citing budget constraints. The program had reported real-time data from more than 80 diplomatic posts.
How the Study Measured Change
Because ground monitors were no longer reporting, the team used satellite aerosol optical depth and compared cities that lost embassy readings with matched controls. They reported no clear pre-shutdown pollution trend, followed by a rise after reporting ended.
Health Context
Translated into fine-particle (PM2.5) terms, the authors offered a range of increases depending on calibration. Even modest sustained rises matter because PM2.5 can enter the lungs and bloodstream and is linked to heart and respiratory disease.
Where Impacts Were Largest
Gains in satellite-based pollution were especially notable in parts of Southeast Asia, the researchers said, including cities where domestic public data had been limited. Advocates argue independent embassy readings had pressured local action; critics of the program cited cost and diplomatic scope.
Related
Air pollution spiked after the Trump administration stopped embassy monitoring.
— Coko (@coko9718) September 15, 2026
Based on the PNAS study and contemporaneous reporting dated September 15, 2026.
