<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>kurthr</author><text>Exhaled breath is about 3.8% or 38000ppm so (20000) that&amp;#x27;s really high! I&amp;#x27;m not too surprised since the turnover rate through a few small holes with a relatively large volume is bad. Reducing the facial volume would help a lot as each breath would expel more CO2 as a fractional percentage.&lt;p&gt;It seems that any sort of face covering or even significant exercise could raise your ambient CO2 level well above 1000ppm.&lt;p&gt;I&amp;#x27;m a bit surprised that levels 38-60x below our exhalation % (and it&amp;#x27;s not lack of O2, because you use up less than 10%&amp;#x2F;breath) has such a significant effect. The one thing that may drive it is that the efficiency of lung ab&amp;#x2F;desorption goes roughly as the square of concentration so a 2% change in CO2 concentration might be enough to have an effect on O2 and blood pH.</text><parent_chain><item><author>Klathmon</author><text>I picked up a CO2 monitor a while ago myself, and the biggest surprise was having it on in the morning in our bedroom with the doors closed. It was easily over 1000ppm IIRC.&lt;p&gt;Ever since then I&amp;#x27;ve made sure to set my AC system to run the &amp;quot;house fan&amp;quot; for 15 minutes or so every hour at night just to circulate the air in the house, and while the numbers went down significantly, anecdotally I swear that I wake up easier in the mornings now.&lt;p&gt;Another surprising place that really high CO2 concentrations show up? The inside of full face motorcycle helmets when at a stop. IIRC they quickly reach as high as 20,000ppm! There is also some speculation that full-face motorcycle helmets that stay closed in an accident are more dangerous in some ways, as the high CO2 concentrations in the helmet can be really dangerous to an unconscious person&amp;#x27;s brain function.</text></item><item><author>Mistletoe</author><text>I own a CO2 monitor and it is shocking how high it can get in a house with two people just existing. 800 ppm or more.  Outside air is 410.&lt;p&gt;In a car with air on recirculate, it was getting to &amp;gt;1220 ppm, a level that impairs decision making and lowers brain function.  I try to drive with air on fresh from now on.&lt;p&gt;I don’t doubt the air in our conference room with 20 people gets super high in CO2 as the meeting goes on, and that would explain a lot of the horrible decisions and thought processes that happen in there. :) I’m going to bring my meter to the next meeting and see what it gets to.  We are a group of scientists so it won’t be awkward or weird.  If nothing else it will spark discussion and reflection on the decisions that are made there.</text></item></parent_chain></comment><story><title>Is Conference Room Air Making Us Dumber?</title><url>https://www.nytimes.com/2019/05/06/health/conference-room-air.html</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>jak92</author><text>&amp;gt; &lt;i&gt;&lt;/i&gt;&amp;quot;house fan&amp;quot; for 15 minutes or so every hour at night just to circulate the air in the house,&lt;i&gt;&lt;/i&gt;&lt;p&gt;Depending on your climate, this could significantly raise the humidity in your house.  Reason is that moisture from the AC coil are wet after the AC turns off.  Typically drips off into the pan until next time AC cycles.&lt;p&gt;If you run the fan you will then evaporate into the air circulating some of the moisture just removed.</text><parent_chain><item><author>Klathmon</author><text>I picked up a CO2 monitor a while ago myself, and the biggest surprise was having it on in the morning in our bedroom with the doors closed. It was easily over 1000ppm IIRC.&lt;p&gt;Ever since then I&amp;#x27;ve made sure to set my AC system to run the &amp;quot;house fan&amp;quot; for 15 minutes or so every hour at night just to circulate the air in the house, and while the numbers went down significantly, anecdotally I swear that I wake up easier in the mornings now.&lt;p&gt;Another surprising place that really high CO2 concentrations show up? The inside of full face motorcycle helmets when at a stop. IIRC they quickly reach as high as 20,000ppm! There is also some speculation that full-face motorcycle helmets that stay closed in an accident are more dangerous in some ways, as the high CO2 concentrations in the helmet can be really dangerous to an unconscious person&amp;#x27;s brain function.</text></item><item><author>Mistletoe</author><text>I own a CO2 monitor and it is shocking how high it can get in a house with two people just existing. 800 ppm or more.  Outside air is 410.&lt;p&gt;In a car with air on recirculate, it was getting to &amp;gt;1220 ppm, a level that impairs decision making and lowers brain function.  I try to drive with air on fresh from now on.&lt;p&gt;I don’t doubt the air in our conference room with 20 people gets super high in CO2 as the meeting goes on, and that would explain a lot of the horrible decisions and thought processes that happen in there. :) I’m going to bring my meter to the next meeting and see what it gets to.  We are a group of scientists so it won’t be awkward or weird.  If nothing else it will spark discussion and reflection on the decisions that are made there.</text></item></parent_chain></comment><story><title>Is Conference Room Air Making Us Dumber?</title><url>https://www.nytimes.com/2019/05/06/health/conference-room-air.html</url></story>