December 2021, MARIETTA, GA ~ Due to its polluting effects, hydrogen chloride (HCl) levels in industrial exhausts are regulated in many countries. To ensure levels are within required limits, HCl monitoring equipment is installed on stacks and scrubbers where the gas is present. However, measuring the gas can be very challenging with commonly used technologies. In situ, probe-type analyzers using tunable diode laser spectroscopy offer a cost-effective, low maintenance and reliable alternative.