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Air pollution in dozens of cities around the world rose after U.S. embassies and consulates stopped monitoring air quality readings last year, according to a study published Monday.

The Trump administration halted the program that published independent air quality data at more than 80 U.S. diplomatic sites in March 2025, citing budget constraints.

Later that year, local air pollution levels increased by between 24% and 33% in 46 of those cities, according to Monday’s study, published in the Proceedings of the National Academy of Sciences.

“This is such a big loss,” said Zoey Zhou, an assistant professor of climate at Columbia University and one of the study’s authors. “Not only for the data, but also for the health impacts and also for accountability.”

The State Department’s program had been linked in a previous study to lower air pollution levels in the cities where it was active. Its pullback came amid other moves the administration has made to curtail climate change research and regulations on air quality. The Environmental Protection Agency repealed limits on greenhouse gas emissions for coal and natural gas power plants on Monday.

The State Department did not respond to a request for comment on the recent findings and on whether the monitoring program will resume.

The program originated in 2008 when the U.S. Embassy in Beijing began to share air quality information from a monitor installed on its roof. The readings, which sometimes topped the Chinese government’s reported levels, drew local anger and pressured Chinese officials to act.

A 2022 study of 50 cities where U.S. embassies began monitoring air quality found that it led to significantly lower air pollution and increased local Google searches for terms like “air quality.”

“The US Embassy monitoring program provided high quality and credible information to the public about the state of their air, often where there were no other sources of such information,” Andrea La Nauze, an associate professor of economics at Deakin University in Australia and one of the authors of the 2022 study, wrote to the Washington Post. (La Nauze was not involved in the most recent report.)

Experts said the monitoring was valuable in cities and countries where local governments did not provide air quality information or offered inaccurate reports.

“This has been very valuable to the citizens of those countries to be able to understand what are the levels of air pollution, and how much trust should they place in the numbers that are published by the national government or by the city or region,” said Kristie Ebi, a professor at the Center for Health and the Global Environment at the University of Washington. “And that has been useful then for people to take action.”

Monday’s study investigated whether air quality gains would continue when that information disappeared, the authors wrote. They used satellite imagery to estimate air pollution levels in 46 cities where U.S. embassies and consulates halted monitoring in March 2025.

By September that year, the aerosol optical depth — a measure of particles in the air derived from satellite imagery that is correlated with levels of PM 2.5, pollutants small enough to enter the bloodstream — around those cities had increased by about 33%. By November 2025, pollution levels had decreased but were still around 24% higher than before monitoring stopped.

A 33% increase in aerosol optical depth corresponds to an increase of about 2 micrograms per cubic meter of PM 2.5, according to the study. The World Health Organization’s global air quality guidelines recommend that average PM 2.5 levels not exceed 5 micrograms per cubic meter each year.

Grouped by region, the largest average increases in aerosol optical depth appeared at sites in Southeast Asia, sub-Saharan Africa, and South Asia, according to Zhou, the study co-author. She cautioned that the number of sites in each region was small and that the study was not designed to isolate particular countries or cities, where readings could have been affected by other local factors.

Zhou wrote that the reduction in air pollution between September and November 2025 could suggest that other sources of air pollution information gradually filled the gap after U.S. embassies stopped their monitoring. But she said the pullback by American diplomatic missions, which issued highly visible and trusted air quality reports, was still a large loss.

Zhou added that her study did not perform a full cost-benefit analysis of the air quality monitoring program for the U.S. embassies involved.

Ebi of the University of Washington, who was not involved in the new study, said that the U.S. embassies’ data was also invaluable to researchers investigating other climate trends affected by air pollution, such as the spread of wildfire smoke and heat waves.

“As a scientist, I don’t understand why there is such a strong focus on removing information,” Ebi said. “Of moving to a situation where people are more ignorant, less knowledgeable about the harms they may be facing … and what actions to take to help reduce those harms.”

The Trump administration is preparing a multibillion-dollar sale of 2,000-pound bombs to Israel in the largest single sale of the controversial munition in recent years, a U.S. official told the Washington Post.

The $2.8 billion package, which would be purchased with U.S. taxpayer dollars, includes 40,000 bombs that weigh 2,000 pounds each, including 20,000 MK-84s and 20,000 BLU-117s, said the official, who like others spoke on the condition of anonymity to discuss military matters. The sale also includes 20,000 I-2000 Penetrator warheads.

Among the most destructive munitions in Western military arsenals, an MK-84 explosion sends metal fragments in every direction for thousands of feet, can rip through metal and thick concrete, and often creates large craters in the earth.

The pending transaction has been informally notified to congressional committees, setting up a potential litmus test for Democrats as frustrations with Israeli Prime Minister Benjamin Netanyahu have created unprecedented strain in the U.S.-Israel relationship.

Though described as a sale, the transaction is financed through a mechanism known as Foreign Military Financing, in which the United States provides the money that Israel uses to buy the weapons.

When asked about the humanitarian concerns, a senior administration official said: “All foreign arms sales are moving through the appropriate process. We do not comment on pending sales.”

The Israeli Embassy did not respond to a request for comment.

The size of the package eclipses previous sales of 2,000-pound munitions to Israel during the Biden administration and the Trump administration, including a controversial $2.04 billion sale in 2025 that bypassed the normal congressional review process.

The 2,000-pound bombs have been employed by Israel on hundreds of occasions in Gaza and Lebanon, playing a significant role in the death toll of those conflicts. Israel has drawn criticism for routinely dropping MK-84s in zones it designated as safe for civilians in Gaza.

“They do like to use them a lot when they’re trying to target any building,” said Trevor Ball, a former explosive-ordnance-disposal technician for the U.S. Army. “If Hezbollah or whoever is in a building, an MK-84 will bring down the whole building.”

Nicknamed the “hammer” by U.S. pilots in the first Gulf War, it is the only munition that President Joe Biden’s administration stopped sending to Israel during the Gaza war out of concern about the killing of Palestinian civilians. That involved suspending a single shipment of the munitions in the spring of 2024. The policy was immediately reversed by President Donald Trump in January 2025, his first month back in office.

“Given the way Israel conducted its air war in Gaza and, to some extent, in southern Lebanon, there are real concerns about how such weapons would be used in densely populated areas,” said Brian Finucane, a senior adviser at the International Crisis Group. “That’s assuming that you have valid military targets to start with because there are concerns about what Israel deems to be valid military targets.”

U.S. support for the sale comes despite several areas of tension between Israel and the Trump administration, including over the violent attacks on Palestinians by Israeli settlers in the West Bank, and ongoing concerns about Israeli military operations in Lebanon and Syria. Israelis also have spurned Trump’s peace plan for Gaza, which involves Hamas disarming in exchange for a withdrawal of Israeli forces.

When the Trump administration struck a short-lived deal with Iran aimed at ending the war there, allies of Netanyahu harshly criticized the agreement and attacked Vice President JD Vance for negotiating it.

As the conflict has dragged on ahead of the midterm elections, Trump and his aides have grown increasingly frustrated with Netanyahu, who pushed for the war on the promise of a quick and decisive victory.

Though the delivery time for such orders can be multiple years, approving such sales sends a broader signal about the bilateral relationship.

“If the Trump administration’s goal is to calm things down in the Middle East, the timing of this is unusual,” Finucane said. “Whether they intend to or not, it sends a vote of confidence to Israel.”

The Trump administration is pressing the leaders of the Senate Foreign Relations Committee and the House Foreign Affairs Committee to approve the sale.

Republican and Democratic leaders historically have backed such sales, but they are starting to face resistance from rank-and-file members regarding U.S. support for Israel stemming from the unpopularity of the wars in Gaza and Iran.

Polls consistently show most Americans oppose the war in Iran, which has raised energy costs and increased inflation. In July, more than 100 House Democrats voted to end all U.S. aid to Israel, signaling a historic shift in the party’s opposition to the country.

Republicans are more unified in their support for Israel, but a growing number of conservative commentators, including Megyn Kelly, Tucker Carlson, and Candace Owens, have questioned Washington’s steadfast backing and the $3.8 billion of aid the U.S. sends to Israel every year.

Besides the MK-84, the sale includes I-2000s, a penetrating bomb body used to attack hardened structures, and BLU-117s, a variant of the MK-84 that has thermal protective coating to make it safer for naval storage.

Iranian strikes have damaged or destroyed hundreds of buildings and other structures at U.S. bases across the Middle East, and caused about $184 million worth of damage at U.S. diplomatic facilities, according to a Pentagon watchdog report.

The inspector general’s report to Congress on Operation Epic Fury — the Trump administration’s name for the war with Iran — also details the extent of U.S. munitions shortages, in the first comprehensive public accounting of the war, which is now in its seventh month.

The report, released Monday, covers operations through June 30. It contains input from the departments of Defense and State and other agencies to provide the most complete picture yet of the cost and military impact of the ongoing conflict.

Buildings and other structures at U.S. bases in Kuwait, Bahrain, Qatar, UAE, Saudi Arabia, Iraq, Oman, and Jordan were damaged or destroyed in the war, the report stated, adding that U.S. diplomatic facilities in Iraq, Kuwait, Saudi Arabia, and the United Arab Emirates also sustained damage.

The mounting costs of the war and impact on U.S. munitions stockpiles has already come under scrutiny. In July, Defense Secretary Pete Hegseth told a Senate hearing that the war has cost $37.5 billion and defended the administration’s request for a further $67 billion to restock the Pentagon’s arsenal and avoid looming budget shortfalls.

The latest report details how the war has “resulted in strategic inventory shortfalls” of munitions and “revealed industrial base bottlenecks for munitions resupply.”

It said the Defense Department is working to “streamline” procurement and production processes, as well as stockpile critical materials, components, and munitions to mitigate the shortage. But while these efforts have begun, the defense industrial base requires “significant lead time” to expand production.

“The most persistent bottlenecks remain in the production of solid rocket motors, the availability of high-grade explosives and propellants, and the recruitment of skilled manufacturing labor,” it states.

The expenditure of U.S. munitions is increasingly worrying U.S. allies and Pentagon officials in the Indo-Pacific region who fear the war in Iran could undermine readiness for a potential conflict with China. The weapons drain has become a source of tension between President Donald Trump and Hegseth, though Trump has denied U.S. weapons are running low.

On Monday, Trump touted U.S. weapons stockpiles in a post on Truth Social, saying he had received a report noting the U.S. is producing “more Exquisite and Elite Weapons than at any time in our History” that were being delivered to U.S. forces.

“A primary focus of this production has been Patriots, THAAD Systems, Tomahawks, and other Standard Missile Systems, of which we already have large numbers in stock,” he said.

The Pentagon and the White House did not immediately reply to requests for comment early Tuesday.

The Washington Post reported in May that the U.S. had depleted much of its inventory of advanced missile-defense interceptors, using up roughly half of the Pentagon’s total inventory of Terminal High Altitude Area Defense, or THAAD, interceptors. The U.S. military also fired more than 850 Tomahawk cruise missiles in the first four weeks of war, a rate that has alarmed some Pentagon officials.

The extent of the munitions the U.S. has used during Operation Epic Fury illustrates the “magnitude and complexity” of the challenge posed by Iran, the report said, noting Iran’s large armed forces, extensive underground facilities, and decades of building a domestic defense industry.

The U.S. launched Operation Epic Fury on Feb. 28 in joint strikes with Israel that killed Iran’s leader at the time, Ayatollah Ali Khamenei. The war has now entered its seventh month, with Iran retaining leverage over the Strait of Hormuz, a critical waterway for oil and gas flows from the Persian Gulf. A recent lightning offensive by Houthi rebels in Yemen, supported by Iran, has threatened to further imperil shipping through the Bab al-Mandab Strait.

Dozens of U.S. aircraft have been damaged or destroyed during the operation, including four F-15E fighter jets, one F-35A damaged in enemy fire over Iran, and several other aircraft and helicopters, the report said.

More than 50,000 U.S. service members have been deployed throughout U.S. Central Command’s area of responsibility in support of the operation, the watchdog report said. A total of 18 have died, the report said, including several in July. It said 417 service members were wounded between Feb. 28 and June 30.

The State Department has also incurred around $113 million in costs, including nearly $80 million responding to events such as the evacuation of U.S. citizens and State Department personnel, the report said, adding that about 9,000 Americans have left the region on charter flights and buses.

The war has also had an “immediate negative impact” on U.S. assistance across the Middle East, including agriculture, food, health, nutrition, and water sanitation, because of the departure of embassy staff, the report said.