https://phys.org/news/2018-10-unexpected-bromine-power-exhaust.html

Bromine species impact the chemistry occurring in the atmosphere as sunlight can convert them into extremely reactive chemicals. These could then react with and alter the breakdown process of compounds such as nitrogen oxides and ozone, which are both pollutants that can have detrimental effects on respiratory health. The ultimate impact of these reactions is still being researched, the authors said.

Bromine species emitted by power plants could also be deposited onto the surface of bodies of water, the study's authors said. There they may transform and react with chemicals introduced to disinfect drinking water. Some of the by-products produced by these reactions are considered possibly carcinogenic after long-term exposure, according to the Centers for Disease Control and Prevention.