What kind of noise are we talking about?
Is it ambient noise (from surrounding)? in which case you may want to get a better microphone.
Is your audio clear and remote audio is noisy? You will need to check conditions over there too.
Or, are we talking about noise when audio is passed through webRTC?
You may want to pass audio through browser defined filters. See firefox examples here.
Note that it will be browser dependent. You may find similar example for Chrome etc.
Or you will need to pass the audio-stream through external filters that can fix the audio quality both at transmitting and receiving end.