2023-08-09 10:17:12
Archive – International Space Station – NASA – Archive
MADRID, 9 Ago. (EUROPA PRESS) –
Concentrations of potentially harmful chemical compounds in dust collected from the air filtration systems of the International Space Station (ISS) exceed those found in dust on the floors of many homes, reveals a new study published in the journal ‘Environmental Science and Technology Letters’.
In the first study of its kind, scientists analyzed a sample of dust from ISS air filters and found levels of organic pollutants higher than average values found in American and Western European homes.
Researchers from the University of Birmingham (UK) and NASA Glenn Research Center (USA) say that they could guide the design and construction of future spacecraft.
Contaminants found in “space dust” include polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCDD), “new” brominated flame retardants (BFRs), organophosphorus esters (OPEs), polycyclic aromatic hydrocarbons (PAHs), perfluoroalkyl substances ( PFAS) and polychlorinated biphenyls (PCBs).
BFRs and OPEs are used in many countries to meet fire safety regulations in commercial and consumer applications such as electrical and electronic equipment, building insulation, furniture fabrics, and foams.
PAHs are present in hydrocarbon fuels and are emitted in combustion processes, PCBs were used in building and window sealants and in electrical equipment such as dielectric fluids, while PFAS have been used in applications as anti-stain agents for fabrics and clothing.
However, their possible effects on human health have led to prohibiting or limiting the use of some of them.
PCBs, some PFASs, HBCDD and commercial PBDE formulations Penta-Octa- and Deca-BDE are classified as persistent organic pollutants (POPs) under the UNEP Stockholm Convention.
In addition, some PAHs are classified as human carcinogens, while the European Chemicals Agency is considering the restriction of some OPCs.
Co-author Professor Stuart Harrad, from the University of Birmingham, highlights it’s a statement that “these results have implications for future stations and space habitats, where it may be possible to exclude many sources of pollutants through careful choice of materials in the early design and construction phases.”
“Although the concentrations of organic pollutants found in ISS dust often exceeded the average values found in homes and other indoor environments in the United States and Western Europe, levels of these compounds were generally within the range found on Earth“, Add.
The researchers note that concentrations of PBDEs in the dust sample that fall within the range of concentrations detected in US household dust may reflect the ISS’ use of inorganic RFs such as ammonium dihydrogen phosphate to make flame-retardant fabrics and fabrics.
They believe that the use of “off-the-shelf” commercial items brought on board for astronauts’ personal use, such as cameras, MP3 players, tablets, medical devices, and clothing, are potential sources of many of the chemicals detected.
The air inside the ISS is constantly recirculated with 8-10 changes per hour.
Although CO2 and trace gaseous pollutant removal occurs, the degree to which this removes chemicals such as BFRs is unknown.
High levels of ionizing radiation can accelerate the aging of materials, including the breakdown of plastic products into airborne microplastics and nanoplastics in the microgravity environment.
This can cause the concentrations and relative abundances of PBDEs, HBCDDs, NBFRs, OPEs, PAHs, PFASs, and PCBs in ISS dust to differ markedly from those in dust from Earth’s interior microenvironments.
The scientists measured the concentrations of a number of chemicals in the dust collected on the ISS.
In a microgravity environment, particles float according to the flow patterns of the ventilation system. and end up being deposited on surfaces and air intakes.
The grids that cover the HEPA filters on the ISS accumulate this residue, so they need to be vacuumed weekly to maintain effective filtration.
The material contained in the ISS vacuum bags is made up of previously airborne particles, clothing lint, hair and other debris generally identified as spacecraft cabin dust.
Some vacuum bags were returned to Earth to study this unique dust, and a small sample was sent to the University of Birmingham for analysis in the study.
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