Why is wet bulb temperature important? How does it effect us?

Question

Edit: Thank you all for the detailed answers! You guys are awesome.

In: 2953

Answer 1

Your body cools down by using sweat.

When sweat evaporates it takes with it a surprising amount of energy.

If you are in a hot space and cannot sweat you cannot cool down.

At any given temperature there’s a maximum amount of moisture the air can hold. For a given humidity the temperature at which the air cannot hold any more moisture is the wet bulb temperature.

If you take a thermometer and wrap it in a wet cloth and blow air on it at the “wet bulb” temperature for the humidity in the room it won’t cool down, because the water can’t evaporate, because the humidity/temperature mix is maxed out.

This is important for humans as if the wet bulb temperature goes about about 37 degrees we lose the ability to keep our bodies at normal operating temperature. If the wet bulb temperature makes it to about 40 degrees you basically start to die. A fan won’t cool you down. Taking your shirt off won’t cool you down. Your body temperature will rise to the wet bulb temperature, shedding enormous amounts of sweat.

If you cannot find somewhere cooler then you’re done for – you’ll succumb to either dehydration or heat exhaustion.

This is being talked about a little more lately as parts of the earth, some with substantial populations, are now seeing wet bulb events at the very edge of what humans are capable of surviving.