The MiniPID2 has a filter which allows for free diffusion of ambient air into and out of the sensor whilst minimising ingress of contaminants and particulates.

The MiniPID2 can also sample from a gas stream passed over the filter exterior. The flow should be a minimum of 100 mbar.L/min, ideally 300 mbar.L and above.

For more information please see the MiniPID 2 manual.