Cross-sensitivity is a sensor's tendency to respond to substances other than the one it is intended to measure.
It is the main reason a single gas channel cannot identify a gas. A reading tells you something in a family of compounds is present, not which one - and treating a cross-sensitive channel as specific produces confident misidentification.
Broadband gas elements respond to whole classes of gases with differing sensitivity. Discrimination comes from comparing several channels with different response profiles, not from any one of them.
A general air-quality element also responds to alcohol, so a cleaning product can produce a reading indistinguishable from a process problem.
Four gas channels with different response profiles are read together, which improves discrimination without making any single channel specific. That is the answer to cross-sensitivity here: not a more selective element, but corroboration between channels that should move together.
