Excellent article on the chemistry of swimming pool disinfectants.

“That urine contains a lot of urea, a nitrogen-laden molecule that reacts with chlorine in pool water to form a DBP [disinfection by-product] called trichloramine. This resultant chemical—not the chlorine itself—helps give indoor pools their distinctive odor and has been associated with respiratory symptoms.”

c&en article

The chemical reactions taking place in your swimming pool:
Urine, sweat, and lotions all react with treated pool water to form chemical by-products, but the jury’s still out on whether those by-products are harmful to your health
By Celia Henry Arnaud