Comparison of sampling collection strategies for assessing airborne trichloramine levels in indoor swimming pools

Abstract

Since 1995, Hery's trichloramine sampling procedure has been widely used to determine trichloramine exposure in indoor swimming pools. This method consists of pumping air at a 1 L/min ow rate for 2 hours through a Te on pre lter and two quartz bre lters. Modi ed Hery methods have been reported using different sampling pump ow rates and types of pre lters. Might the pre lter type or sample collection pump ow rate have in uenced these studies' results. This study aims to evaluate the effects of different cassette assemblies and sampling ow rates on the levels of measured trichloramine.Laboratory tests were performed using a trichloramine production set-up designed for this study. Workplace measurements were carried out in four indoor swimming pools. Different pre ltering strategies were used: no pre lter, glass pre lter or Te on pre lter in the sampling cassette, and an original separable pre lter cassette is presented in this study Laboratory tests indicated that in the situation of trichloramine concentrations higher than 1 mg/m³, the trichloramine percentage captured on the rst lter could pass the value of 75%, which demonstrates the possible loss of material during the sampling. The investigation of the pre lter effect on sampling strategy using different cassette assemblies revealed that using a separable cassette assembly could prevent overestimating the trichloramine levels. Furthermore, there were no signi cant differences between measured TCA concentrations at different ow rates (from 0.5 L/min to 2 L/min) in swimming pools.