3 ms·

I think the idea is though that the car air is already compromised. e.g. they have opened the doors to get into the car, then closed the doors and enabled the B

• dmlorenzetti 10y ago
  It needs to filter the air from outside and get it into the car to quickly displace the air already inside the vehicle that is contaminated. In exactly the same way that recirculating air from inside the vehicle is easier on your air-conditioner, recirculating interior air is easier on the filter. With the A/C, you want some minimum outside air to get rid of CO2 and whatever other effluents the passengers and materials in the car are generating. But if you were driving through a plume of toxic gas/particles, you wouldn't mind smelling your armpits and a little extra CO2 if it meant extra protection from whatever is out there. Hence I believe that if you were really designing a Bioweapon Defense Mode, you would cut the intake of outside air to an absolute minimum. You might not go for zero flow, because you might want to pressurize the cabin a bit (in the U.S., most building mechanical systems are set up this way). But I wouldn't expect to cycle through enough outside air that you could halve the concentration in that bubble (which is probably 10-20 car volumes or more) in less than 15 minutes, as their graph shows.