Reference

Cross-sensitivity is a sensor responding to a gas it was not built to measure, and it is not a defect but a property of the sensing chemistry itself. This guide covers the mechanism, the interference patterns crews actually meet, the under-reporting direction nobody expects, and how to diagnose a suspect alarm from clean air.

A 4-gas monitor shows four channels in three different units, and they are not comparable to each other. This guide reads the display field by field: the clean-air baseline, what an oxygen drop implies, why 10% LEL is not 10% gas, what the LOW, HIGH, TWA, STEL and PEAK labels mean, and which hazards the four channels cannot see at all.