A dehumidifier assembly includes an extraction chamber coupled in flow communication with a sample air inlet, a sample air outlet, and a sample drip opening. The extraction chamber is configured to receive a sample air flow therethrough at substantially atmospheric pressure from the sample air inlet to the sample air outlet. The dehumidifier assembly also includes a conduit positioned within the extraction chamber. The conduit is coupled in flow communication with an environmental air inlet and an environmental air outlet, and is sealed with respect to the extraction chamber. The dehumidifier assembly further includes a circulator coupled to the environmental air outlet. The circulator is operable to create a negative pressure in the conduit, such that an environmental air flow is drawn through the environmental air inlet into the conduit. The conduit is configured to facilitate heat transfer from the sample air flow to the environmental air flow.