"An important implication of the current study is to reduce the use of bleach to disinfect areas potentially contaminated with SARS-CoV-2, as hypochlorous acid may inadvertently increase the length of time SARS-CoV-2 remains infectious in the air. Nevertheless, the reaction between SARS-CoV-2 and volatile acids released by cleaning products must be further studied."

In the study researchers acidified the airflow with nitric acid in the humidifying bubbler diluted to pH 5, not hypochlorous acid as used in (most) bleaches.

pH 5 hypochlorous acid (a weak acid) is about 1000 times more concentrated than pH 5 nitric acid (a strong acid), and, while both are strong oxidizers the oxidative effect of the hypochlorous acid in terms of its disinfecting potential by denaturing viral proteins is sure to predominate over the supposedly boosted infectivity due to slightly lower pH, I mean, nobody would use bleach as disinfectant if it didn't.