An air pollutant found in industrial areas, magnetite, could be contributing to the development of neurological conditions such as Alzheimer’s disease (AD), according to new study out of the United Kingdom and Mexico.

The study, “Magnetite pollution nanoparticles in the human brain,” was recently published in the journal Proceedings of the National Academy of Sciences.

Physicist Barbara Maher, co-director of the Centre for Environmental Magnetism and Paleomagnetism at Lancaster University in the U.K., sought to understand whether magnetite in the human brain comes from pollution, since the compound is a common component of the smoke emitted from power plants. Magnetite is a magnetic mineral made up of iron and oxygen.

Maher and colleagues studied brain samples from the frontal cortex of 37 people who had died of various causes. The samples came from people who had lived in Mexico City and in Manchester, U.K. The scientists used several imaging techniques to determine the level of magnetite in the brain samples.

Researchers found nanosphere magnetite particles, which is unusual because magnetite is typically tetrahedral or octahedral. They also found platinum, nickel, and cobalt, all metals not naturally found in the brain. This indicated that the deposits likely came from the environment.

According to Maher, nanospheres also likely suggest that the particles came from environmental pollution. “They showed all the properties suggesting they formed in high temperatures. [The nanospheres are] combustion byproducts, like what’s found in power station pollution,” she said in an interview with Science magazine.

Currently, it is not completely clear whether magnetite can be added to the risk factors for AD and other neurological conditions, but its identification in this study indicates that brain magnetite deserves more attention by researchers and those making decisions about air emission policies. “It’s an unfortunately plausible risk factor, and it’s worth taking precautions. Policymakers have tried to account for this in their environmental regulations, but maybe those need to be revised,” Mahler said in the interview.

Dr. David Reynolds, chief scientific officer, Alzheimer’s Research UK, stressed to the Science Media Centre that additional research is needed before a link to AD or another neurological condition can be assumed. “We know that air pollution can have a negative impact on certain aspects of human health, but we can’t conclude from this study that magnetite nanoparticles carried in air pollution are harmful to brain health,” Reynolds said. “It’s important to continue to study the impact of lifestyle and environment on brain health, although age and genetic risk factors also play an important role in influencing a person’s risk of Alzheimer’s.”