Bromine Escape Can Offset the Health Benefits of Mercury Emission Control Using Bromine Injection Technology

Abstract Coal-fired power plants (CFPPs) are one of the largest contributors to anthropogenic mercury (Hg) emissions, which are regulated under the Minamata Convention on Mercury. Bromine injection technology has been recognized as an effective strategy for reducing mercury emissions. However, the comprehensive environmental impacts of potential bromine (Br) escape using this technology remain unexplored. This study evaluates the possible effects of using bromine injection technology on Hg and Br emissions into the atmosphere, Hg cycle, and Hg-related health effects. Our results indicate that this Hg control technology would increase Br emissions and consequently accelerate local Hg oxidation and deposition, thereby partially offsetting the health benefits from reduced Hg emissions. At bromine injection dosages of 30–120 mg kg–1 coal, CFPPs Hg emissions decrease by 101.9–188.8 Mg yr–1, but bromine escape increases CFPPs Br emissions by 30.8–123.2 Gg yr–1. At the highest dosage, the Br-escape-driven chemical effect yields a global increase of 2804 premature cardiovascular deaths and 7.48 × 105 newborn IQ-point loss. Therefore, we highlight that the substantial impacts of Br escape as well as its control must be carefully considered before bromine-based Hg emission control technology is applied.