You probably don't put a lot of thought when you hit the brakes in your car on a commute or trip to the store, but one group of researchers have been thinking about it quite a bit and they say what they found was worrisome.
It's something researchers say could be making you sick.
In a study, the Georgia Institute of Technology looked at the chemicals that go in the air once drivers apply their brakes.
Earth Sciences Professor Athanasios Nenes explains, "you generate soluble amounts of iron, copper and manganese and that soluble component is what actually causes the adverse health effects."
The problem is acidic sulfate particles already in the air break down the chemicals to where our bodies can ingest them.
Researchers say that mixture is not good.
"Whenever you breathe in soluble metals essentially they act as catalysts to deplete your body of anti-oxidants," said Nenes.
Some cars have ceramic brakes, but those are more expensive and tend to be found on higher-end vehicles.
The Motor and Equipment Manufacturers Association looked at the study and responded with a statement.
They said their companies, "have committed significant resources in developing reformulated products that meet the highest safety and performance standards, while phasing out of the use of copper and other metals."
Nenes says until all brakes are made from safer materials, it's probably a good idea to roll up your windows.
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