Sudbury health officials keep Atkinson Pool closed after high combined-chlorine readings; UV, HVAC and draining considered

Sudbury health officials said the Atkinson natatorium (lap pool) will remain closed while town staff investigate persistently elevated combined-chlorine levels, known as chloramines, that can harm indoor-air quality and irritate swimmers.

Vivian, Sudbury health director, told the Board of Health that an inspection during swim practice found the lap pool’s combined-chlorine reading at 0.6 parts per million on Jan. 8, above the state pool code standard of 0 to 0.2 parts per million. The town closed the natatorium that day and applied multiple “shock” treatments to the lap pool; those treatments reduced levels in the short term but did not bring the lap pool into sustained compliance, Vivian said.

The closure matters because chloramines — formed when free chlorine reacts with nitrogen-containing contaminants like sweat or urine — accumulate in indoor pools, worsen air quality near the deck and can cause eye, skin and respiratory irritation. Vivian said chloramines are denser than air and can linger near pool decks, “which is why when facilities put in those large commercial industrial fans on the pool deck, it really helped move…