Question
Hi, I'd like to know whether the moisture in the fog can have a dampening effect for sounds? It always feels quieter on a foggy night than a clear night, and I wonder if it's due to ambient sounds being dampened.
Answer
Chris - It definitely does. Yeah, great question, Charles.
The reason for that is the fog consists of tiny particles of water, which are suspended as little blobs in the air down at ground level and sound is the compression wave that travels through air.
So, when the compression wave goes through the air, it's making air molecules vibrate and they're passing those vibrations from one to the next like a hand shake.
If you put water molecules into air, it means that the water can soak up some of the vibrations and this will attenuate or damp down quite literally (excuse the pun) the transmission of that sound through the air.
So, fog does have a sound-attenuating effect; the other reason why it might is that, when it's foggy, people tend to slow down too. So, people don't go out as much. They don't play games as much. They don't drive as much and as a result, you might see a reduction in the overall sound...
Comments
Humidity is not the same a fog
Higher humidity will decrease the attenuation of sound, as it reduces the vibration relaxation of air.
Fog occurs when the temperature is almost as low as the dew point, and water droplets begin to form in the air. The higher the humidity the more will form.
These water droplets cause scattering of the noise, where noise is both refracted and absorbed by the water particles, lowering its traveling distance. This will only impacts on high frequency noise, as low to mid frequency noise have such large wave lengths that they just go around small obstruction such as water particles.
Actually, it’s the other way around
Apparently sound can travel farther and is therefore louder in humid air than dry air. Fog is basically 100% humidity. The perceived quietness is more likely psychological or a result of people not being active.
https://www.sweetwater.com/insync/effects-of-temperature-humidity-live-s...
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