The grandiosely named mode is a HEPA air filtration system found in the Model S and Model X that is designed to remove pollen, bacteria, and pollution from the outside air before it enters the vehicle's cabin. In a blog post Tesla says it tested the system in environments ranging from landfills to polluted cities in China with excellent results. But they wanted to take things a step further and encased a Model S in a bio dome purposely filled with extreme level of pollutants—so much so the testers needed to wear gas masks to breath. Within two minutes of the Bioweapon Defense Mode being activated the system removed the pollutants so well none were detectable in the cabin anymore. And within ten minutes the Bioweapon Defense Mode reduced the pollutants in the air outside the car by 40%.
"In other words, Bioweapon Defense Mode is not a marketing statement, it is real. You can literally survive a military grade bio attack by sitting in your car," Tesla wrote after the tests.