Which factor is known to deactivate bromine in pool water?

UV light is known to deactivate bromine in pool water by breaking down the bromine molecules through a photochemical reaction. Bromine is effective as a disinfectant and sanitizer in swimming pools, but when exposed to UV light, its efficacy diminishes. This is particularly relevant for outdoor pools or those with significant sunlight exposure, as the ultraviolet rays can lead to a decrease in bromine levels, requiring pool operators to monitor and possibly adjust the bromine concentration more frequently to maintain proper sanitation.

In comparison, chlorine, heat, and cyanuric acid do not have the same direct effect on bromine's activity. Chlorine itself is a separate disinfectant that can work alongside or in place of bromine, but it does not deactivate bromine. Heat impacts chemical reactions, including those involving sanitizers, but it does not directly deactivate bromine. Cyanuric acid acts as a stabilizer for chlorine and does not have a deactivating effect on bromine.