Biowar Experts Quibble Over Model X Defense Mode

Tesla Model X climate control system

When it unveiled the sold-out Tesla Model X to the world on September 29, Tesla revealed for the first time some of the car’s unique features, including individually adjustable single pillar rear seats, self opening and closing front doors and a Bioweapon Defense Mode built into the Model X climate control system. According to the company,

The bio defense button is designed to allow clean medical-grade air into the cabin and keep contaminated air out. When deployed, it pushes the system into full fresh mode, pulling all HVAC air through the HEPA filter. The fan goes to max speed 11, pulling in enough air to slightly pressurize the cabin, keeping other air from entering (the Tesla) Model X.

OK. We get it. The HEPA filter that is the heart and soul of the ventilation package really does a great job of keeping allergens, bacteria and odors out of the cabin of the car. But is it really a bioweapon defense system? Some would beg to disagree.

Colonel Randall Larsen, retired from the U.S. Air Force and now the director of the Institute for Homeland Security, says he has wanted to buy a Tesla for a long time. “I’m actually building a new house, and I had them put an electrical charger in the garage, just in case I buy a Tesla,” he told Gizmodo recently. But when told about the Tesla Model X’s “bioweapon defense mode,” he laughed out loud and asked, “So, is Musk actually advertising this?

A HEPA filter must be able to remove 99.97% of 0.3 micrometer particles from the air. A 0.3 micrometer HEPA filter is fine enough to catch bacteria like anthrax, which ranges from 1 to 1.2 micrometers across. It will also stop the plague and most other bacteria, as well as most pollen, dust, and fungal spores. “Now, if you’re worried about bacterial agents like anthrax or plague, a good filtering system would probably protect you,” said Larsen.


Tesla Model X Biohazard Mode


But viruses are much smaller than bacteria, which means they’re harder to filter out of the air. “Well, 0.3 micrometer won’t hold back viruses. It will hold back most bacteria, but it won’t hold back viruses. So, if you believe that all bioterrorist agents are bacteria, then you’ll get an increment of protection,” said Michael J. Buchmeier, deputy director of the Pacific Southwest Regional Center for Biodefense and Emerging Diseases at the University of California, Irvine.

The influenza A virus is 80-120 nanometers wide, so it can pass through even a 0.2 micrometer HEPA filter without a problem. “It’s a statistical game that we play,” said Buchmeier. “Any filter like that is going to be efficient to a degree but it’s not necessarily 100% efficient.” Plenty of viruses are large enough to get caught by a HEPA filter but small enough to get through an ordinary cabin air filter, so the HEPA system probably does help. The trouble is that there are a lot of viruses out there that it can’t stop, including some with bioweapons potential.

Both men point out that a real bioweapons attack will be so stealthy that, by the time we know one is underway, it will be too late to press that button on the dashboard (or touchscreen, if you are driving a Tesla). Buchmeier says just driving is a pretty good defense against such hazards. “Our protection there is dilution. Think about how much air passes over a car going at highway speed, and how little of that air is actually inhaled by the occupants of the car,” he says.

None of this is to say that the air filtration system in the Model X is not superior to anything available from any other car manufacturer. It is. The question is, why open the company up to such quibbles from the likes of Larsen and Buchmeier in the first place?

The key may be that the the company chooses to have the fan speed control for the system go to 11 — a further take-off on a joke from the movie “This Is Spinal Tap”. The controls for the Tesla audio systems also go to 11. The term Ludicrous Mode featured on its fastest cars is swiped from Space Balls, the Mel Brooks spoof of Star Wars.

In the end, Buchmeier sums it up best. The Model X system really can do a superior job of filtering out allergens like ragweed and cedar pollen, fungal spores like the ones that cause Valley Fever, and irritants like smoke and dust. It could also filter out unpleasant roadside odors. “There are a lot of reasons why you would put a filter like that in, and only one of them is bioterrorism,” he says.

What do you think? Should Musk be talking about those other benefits of highly filtered air instead of creating controversy with claims that do little if anything to advance the company’s stated objective of bringing the electric car revolution to the masses, or is that controversy doing exactly that- by sparking conversations about Tesla with people who may not have been interested in the company before? Let us know what you think.


Steve Hanley

Closely following the transition from internal combustion to electricity. Whether it's cars, trucks, ships, or airplanes, sustainability is the key. Please follow me on Google + and Twitter.