H2S leak detection near Compressors

I've come across point type H2S detectors in general for H2S detection near Compressors. However this may not be an effective way of measuring whenever H2S drifts away from the point type detectors and that may be dangerous too from safety point.Iam looking for H2S leak detection that can cover broader envelope i.e. with an encasing around the Compressor?? or some such arrangement (I know that, it may not be feasible from maintenance point)

Is there any cone type H2S detectors and if so can anyone suggest the manufacturer or any better way of measuring.

Thanx in advance