A recent study by a group of scientists has revealed that the extent of harmful pollutants discovered in dust in the International Space Station's (ISS) air filters exceeded the median levels of those lodged in the floors of several households across the United States and Western Europe.
The hazardous elements detected within this "space dust" include certain persistent organic pollutants (POPs) like polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), some per- and poly-fluoroalkyl substances (PFAS) or “forever chemicals,” and hexabromocyclododecane (HBCDD). Also, other harmful substances are the newly recognized brominated flame retardants (BFRs), organophosphate esters (OPEs), and polycyclic aromatic hydrocarbons (PAHs).
“Our findings have implications for future space stations and habitats, where it may be possible to exclude many contaminant sources by careful material choices in the early stages of design and construction,” co-author Stuart Harrad, a professor of environmental chemistry at the University of Birmingham, noted.
The research team discovered that some PAHs are carcinogens, and the European Chemicals Agency might restrict some OPEs. BFRs and OPEs are used globally for fire safety in electronics, insulation, furniture, etc. PAH results from fuel combustion, while PCBs are used in building materials. PFAS is found in firefighting foams and consumer products. PBDE's presence in ISS dust may be from inorganic fire retardants.
The International Space Station has hosted humans for over two decades since its 1998 launch. Due to the fire risk in spacecraft, the flammability of ISS materials is closely monitored, the scientists expressed.
ISS air is recirculated 8 to 10 times per hour, removing carbon dioxide and contaminants, but its ability to eliminate flame retardants and certain chemicals remains uncertain. The study also found that everyday items like cameras, MP3 players, tablets, medical devices, and clothing could be sources of the detected chemicals.
A report released by the American Lung Association in April 2023 disclosed that more than 119 million US residents, accounting for almost a third of the population, reside in environments with air pollution that can compromise their health and longevity. The publication, which mainly highlighted particle and ozone pollution, hinted that millions of Americans expose themselves to health risks each time they are outdoors.
The issue of particle pollution continues to loom large in the US. They are microscopic at just 1/20th the diameter of a human hair, and can evade the body's usual protective mechanisms. Consisting of a mixture of solid and liquid droplets such as dirt, dust, soot, or smoke, they can lodge within the lungs or even be absorbed into the blood circulation. Research has highlighted the potential of exposure to these particles to trigger cancer and other harmful health effects.
However, Harrad and his colleagues found chemical concentrations similar to those on Earth and believe their findings could aid future off-world planning.
“The results do have implications for future space stations and habitats, where it may be possible to exclude many contaminant sources by careful material choices in the early stages of design and construction,” they stated.