Air strikes cause black rain and ‘unprecedented’ pollution in Tehran, scientists say
Air Strikes Trigger ‘Unprecedented’ Pollution and Black Rain in Tehran, Scientists Report
On Monday, satellite imagery captured smoke drifting over Tehran, attributed to strikes on oil depots and refineries, as the World Health Organization (WHO) raised alarms about potential health hazards linked to the attacks. Since the US-Israeli assault on Iran began on 28 February, at least four oil installations around the capital have been targeted. Residents described the air quality as severely degraded, with smog obscuring sunlight and a persistent burning odor in parts of the city.
Verified Satellite and Video Evidence
Images from 9 March, analyzed by BBC Verify, showed two oil facilities in Tehran still ablaze after overnight air strikes. Smoke was also visible from Shahran depot in the northwest and the Tehran oil refinery in the southeast. Footage of the refinery’s aftermath revealed massive fireballs lighting up the sky, according to verified clips. However, the combination of smoke and cloud cover has made it difficult to evaluate the full damage to the hit sites.
On Sunday, emergency personnel were seen inspecting scorched oil tankers and ruined buildings at Shahran. The Israel Defense Forces (IDF) claimed to have targeted “fuel depots” near Tehran, including the refinery, in a March 7 post on X. BBC Verify shared coordinates of this and three other sites with the IDF and Pentagon for confirmation. While the IDF denied striking those locations, the Pentagon has yet to respond.
Chemical Composition of the Pollution
Experts highlight that oil refinery strikes generate a complex mix of pollutants. Incomplete combustion releases carbon monoxide and soot instead of carbon dioxide and water, while sulfur and nitrogen oxides can form acids when mixed with rainwater. These emissions also include hydrocarbons, metallic compounds, and oil droplets, creating a unique blend of contaminants. A Tehran resident in her 20s noted the distinct burning smell, stating,
“I can’t see the Sun. There is a horrible smoke. It’s still there. I’m very tired.”
Scientists stress that the pollution’s chemical profile is unlike anything seen in cities such as Beijing or Delhi, which typically face smog from industrial activity. Dr. Akshay Deoras, a research scientist at the University of Reading, called the situation “unprecedented,” explaining,
“What has happened [in Iran] is definitely unprecedented because it’s all coming in from missiles dropping in and airstrikes on oil refineries.”
Eloise Marais, a professor at University College London, added that the variety of pollutants is “definitely unusual,” comparing it to a severe industrial accident where an entire refinery explodes.
Black Rain and Atmospheric Impact
Tehranians reported heavy downpours of “black rain” on Sunday, a term for rainfall tainted by airborne pollutants. Normally, rain helps clear the atmosphere, but black rain indicates high concentrations of soot and other toxins. Deoras explained,
“The raindrops acted like little sponges or magnets, collecting whatever was in the air as they fell, which is why residents observed what’s being described as ‘black rain’.”
Some particles may have settled independently of rainfall, exacerbating the pollution’s effects.
