The manual from the online Lexus service says:
"Micro dust and pollen filter button.
Operates micro dust and pollen filter on/off. Outside air mode switches to (recirculated air) mode. Pollen is removed from the air and the air flows to the upper part of the body. Usually the system will turn off automatically after approximately 3 minutes."
But I'm not sure why you would want to bypass it. I know our Prius always filters the air.
"Micro dust and pollen filter button.
Operates micro dust and pollen filter on/off. Outside air mode switches to (recirculated air) mode. Pollen is removed from the air and the air flows to the upper part of the body. Usually the system will turn off automatically after approximately 3 minutes."
But I'm not sure why you would want to bypass it. I know our Prius always filters the air.