"Black rain" and airstrike-caused pollution in Iran could pose unique health threats to pregnant people — here's what one researcher wants you to know

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Over the past week, multiple accounts from Iran have described "acid rain" and "black rain" falling from the sky and seemingly coating surfaces in a thick film. Experts have linked the reports to American and Israeli airstrikes on fuel depots in the country, warning that the resulting air pollution and water contamination could have health and environmental impacts, with potentially long-term consequences.

With this type of contamination, "Even at the lowest level, there's still harm," ​​Marsha Wills-Karp, the Anna M. Baetjer Professor of Environmental Health and Engineering at Johns Hopkins Bloomberg School of Public Health, told CG.  

Recent strikes on Iran began on February 28. Strikes on desalination plants reportedly threatened water supplies amid an ongoing water crisis in the drought-affected region. And, according to ABC News, fires following the March 7 and 8 strikes on oil reserves "burned for multiple days," with local officials cautioning residents to avoid exposure to the resulting pollution.

"The black rain and the acidic rain ​… is indeed a danger for the population, respiratory mainly," a spokesperson for the World Health Organization said in a press briefing on March 10, according to Reuters. The outlet spoke with research scientist Akshay Deoras, who noted that while the visibly black rain was an alarming indicator of debris mixing with precipitation, long-term exposure to the toxic air may pose the most significant health threats.

Gabriel da Silva, Associate Professor of Chemical Engineering at the University of Melbourne, wrote at The Conversation that the pollutants may include a mix of carcinogenic hydrocarbons, sulfur dioxide, nitrogen dioxide, heavy metals, and very fine inhalable particulate matter — known as PM2.5 when measured at diameters of 2.5 micrometers or smaller. 

Exposure to PM2.5 — often studied in relation to wildfires, industrial operations, and traffic-related pollution — has been associated with serious health concerns, including increased respiratory symptoms, decreased lung function, cardiac problems, and premature death for those with heart or lung disease.

The New York Times reported accounts of migraines, dizziness, and coughing in the wake of the recent pollution in Iran. Wills-Karp, the Johns Hopkins researcher, told the outlet earlier this week that coughing is a protective mechanism, as people "[clamp] down on [their] airways to keep those substances from getting in."

For pregnant people, exposure to toxins and especially particulate matter may pose unique risks. CG followed up with Wills-Karp to learn more about the potential pregnancy complications and maternal health issues linked to the pollution — and what might be done to help mitigate exposure.

Studies have indicated that exposure to PM2.5 can induce cellular inflammation. In pregnant people, "inflammation can destroy the architecture of the placenta," Wills-Karp told CG. "It can disrupt the membranes between the placenta and the mother, the maternal-fetal interface, and cause preterm delivery."

Preterm birth is a risk for low birth weight and is associated with higher rates of infant death and disability, according to the Centers for Disease Control and Prevention. 

Much of the research into potential links between PM2.5 exposure and pregnancy outcomes has investigated more chronic exposures. "It does bring to mind: What's the effect of a much higher dose in a more acute setting?" Wills-Karp posed. "I would say that with just a massive amount of those chemicals in a short period, probably preterm birth would be greatly increased."

The researcher went on to note, "There are other things that take place in the mother in response to particulate [matter] and other harmful toxins." She explained that exposure can also affect a pregnant person's "blood pressure and their cardiac output. And that can also cause preeclampsia and other kinds of adverse effects."

But according to Wills-Karp, there are ways to help mitigate exposure to pollution from burning oil and from building materials that may burn in widespread fires.

"People should be wearing masks, preferably N95s, because … those particles that are harmful are very small, so they can go through a regular mask," she said. "But you also need to wear one of those when you're cleaning up this debris."

Wills-Karp noted that precautions should be taken when dealing with contaminated surfaces as well. 

"And wear gloves if you can when you're cleaning surfaces. Try not to just spread it around. Make sure you try to get rid of it and don't expose yourself," said Wills-Karp, who also recommended educating family members to reduce exposure. "Kids tend to put everything in their mouths and get it on their skin, so keep them away from those surfaces."  

Wills-Karp underscored inequitable access to high-quality masks as a concern but said that the COVID-19 pandemic may have increased awareness of masks as an important tool, with some families possibly having supplies already on hand and humanitarian agencies potentially more prepared to deploy them.

In the event that people cannot access these masks, however, she recommended that they use scarves or other fabrics to cover their mouths and noses, ensuring that they can still breathe through the layers. Such fabrics should also be washed frequently to reduce the buildup of contaminants.

One goal at Climate, Gendered is to bring a spotlight to the reality that proliferating pollution, increasing temperatures, rising seas, extreme weather, habitat loss, and more can uniquely and disproportionately impact girls, women, trans communities, and nonbinary people — especially those from communities of color, Indigenous people, disabled people, immigrants and displaced people, people experiencing poverty, and residents of low- and middle-income countries. We're also interested in the climate crises and concerns that can disproportionately affect men and boys. 

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