Question

a landfills gas monitoring system primarily detects which of these? methane ozone argon water vapor

Explanation:

Landfills produce methane as organic waste decomposes anaerobically. Methane is a potent greenhouse - gas and a key gas to monitor in landfills. Ozone is not a major gas produced in landfills. Argon is an inert gas and not a product of landfill processes. Water vapor, while present, is not the primary gas of concern in landfill gas monitoring.

Answer:

methane