The emergence of heat and humidity too severe for human tolerance (2020)
I see a lot of uninformed people on this thread thinking 35C wet bulb temperature isn&#x27;t such a big deal and proposing various ineffective tips to cool down.<p>Let me explain what the issue is, in simple words:<p>WET BULB TEMPERATURE IS NOT TEMPERATURE YOU SEE ON A THERMOMETER. (please, don&#x27;t nitpick, I am aware of wet bulb thermometers)<p>Wet bulb temperature is combination of temperature and humidity.<p>The simple layman way to understand it is it says what minimum temperature an object can attain by evaporating water off it, in perfect conditions (forced airflow, full shade, no internal heating, etc.)<p>When air is dry, even if it is hot you can evaporate sweat and cool down -- the wet bulb temperature is low in dry air.<p>You can survive on Sahara because while the air can be very hot, it is also dry. You sweat and you cool down.<p>As the humidity rises, the wet bulb temperature approaches dry bulb temperature and at 100% humidity they are both the same.<p>When air is 100% humid you cannot cool down by sweating at all -- the sweat will not evaporate in 100% humidity regardless of temperature.<p>Meaning that an air with 35C and 100% humidity has 35C wet bulb temperature but so can hotter air that has less than 100% humidity. The hotter air the lower humidity is needed for the object to cool down to 35C.<p>Wet bulb of 35C is a limit of human endurance. Even if you lie down in shade and do nothing and are completely healthy, your body is barely able to remove enough heat to survive. Any higher temperature and you <i>WILL</i> eventually die.<p>People who need to work (like move around at all) or are sick or are small (kids) will die faster.<p>The only way to resolve this issue is to dry the air somehow.<p>Things that don&#x27;t work:<p>-- going into shade. You are still going to die, just a little bit slower.<p>-- having a fan. It can&#x27;t cool you down, because water will not evaporate to cool anything below wet bulb temperature. You are going to die.<p>-- going into cellar. The air will get cooler but the humidity will rise. You are going to die, unless you can cool the air DRY BULB temperature below 35C. At which point your cellar will have water condensing on its  walls which means you can remove humidity from air. It will be shitty, wet, 100% humid, hot place, to sit half a day in with your family, kids and neighbors that don&#x27;t have an expansive cellar like you, but at least you will survive. Yay...<p>The issue is in areas that tend to be very hot and susceptible to this phenomenon, people tend to not have means to dry the air. They either don&#x27;t have money for equipment or they have open homes (who keeps their home shut in a climate like that) assuming they have home at all.<p>From economic point of view, the problem is that even under wet bulb temperature of 35C some people will already be dying and others will have to stop whatever they are doing, which is not good for your economy.