<instructions>Your goal is to analyze the following comment and estimate how highly it will be upvoted by the Hacker News community.</instructions><comment><author>idoco</author><text>I disagree, and I can tell you from first hand experience that this is how a tank NBC protection system works - The crew cabin is pressurized with high flow of filtered air.&lt;p&gt;&lt;a href=&quot;http:&amp;#x2F;&amp;#x2F;elbitsystems.com&amp;#x2F;Elbitmain&amp;#x2F;files&amp;#x2F;Kinetics_NBC-CBRN.pdf&quot; rel=&quot;nofollow&quot;&gt;http:&amp;#x2F;&amp;#x2F;elbitsystems.com&amp;#x2F;Elbitmain&amp;#x2F;files&amp;#x2F;Kinetics_NBC-CBRN.pd...&lt;/a&gt;&lt;p&gt;[Edit - adding this] 
I can also say, that this creates a very uncomfortable sensation in your ears while the cabin is being over-pressurized (about 2 minutes)</text><parent_chain><item><author>dmlorenzetti</author><text>&lt;i&gt;Bioweapon Defense Mode is not a marketing statement, it is real.&lt;/i&gt;&lt;p&gt;Their filter does a good job cleaning particles out of the cabin air.  Good on them.&lt;p&gt;Nevertheless, calling it &amp;quot;Bioweapon Defense Mode&amp;quot; is clearly a prize bit of marketing.  A system designed to protect against an external bioagent wouldn&amp;#x27;t run huge amounts of outside air through the filter.  That would just load the filter more quickly, impacting its performance (for chemical agents) and&amp;#x2F;or its energy requirement (for particles).  Instead, you would cut the outside air intake as much as you could get away with, in order to buy the occupants time to drive clear of the plume.&lt;p&gt;Since they claim that the car is responsible for the decrease in the particle concentration in the test chamber, they must be running a pretty high flow of ambient air through the system.  Of course, the ambient concentration would decrease even without the car&amp;#x27;s filter, due to particle deposition, and possibly due to losses in the sampling instrument.  But then you only report those other loss rates if you&amp;#x27;re interested in science, rather than in marketing.</text></item></parent_chain></comment><story><title>Putting the Tesla HEPA Filter and Bioweapon Defense Mode to the Test</title><url>https://www.teslamotors.com/blog/putting-tesla-hepa-filter-and-bioweapon-defense-mode-to-the-test</url></story>
<instructions>Your goal is to analyze the following comment and estimate how highly it will be upvoted by the Hacker News community.</instructions><comment><author>bobbles</author><text>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 BDM.&lt;p&gt;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.&lt;p&gt;At the point where the air is clean though it would be a good idea to make the car it&amp;#x27;s own little safe haven and allow the occupants to drive to safety (hell it could even drive itself to safety if it can sense when the air is safe again outside)</text><parent_chain><item><author>dmlorenzetti</author><text>&lt;i&gt;Bioweapon Defense Mode is not a marketing statement, it is real.&lt;/i&gt;&lt;p&gt;Their filter does a good job cleaning particles out of the cabin air.  Good on them.&lt;p&gt;Nevertheless, calling it &amp;quot;Bioweapon Defense Mode&amp;quot; is clearly a prize bit of marketing.  A system designed to protect against an external bioagent wouldn&amp;#x27;t run huge amounts of outside air through the filter.  That would just load the filter more quickly, impacting its performance (for chemical agents) and&amp;#x2F;or its energy requirement (for particles).  Instead, you would cut the outside air intake as much as you could get away with, in order to buy the occupants time to drive clear of the plume.&lt;p&gt;Since they claim that the car is responsible for the decrease in the particle concentration in the test chamber, they must be running a pretty high flow of ambient air through the system.  Of course, the ambient concentration would decrease even without the car&amp;#x27;s filter, due to particle deposition, and possibly due to losses in the sampling instrument.  But then you only report those other loss rates if you&amp;#x27;re interested in science, rather than in marketing.</text></item></parent_chain></comment><story><title>Putting the Tesla HEPA Filter and Bioweapon Defense Mode to the Test</title><url>https://www.teslamotors.com/blog/putting-tesla-hepa-filter-and-bioweapon-defense-mode-to-the-test</url></story>