Understanding Mist in Airplanes: The Science Behind the Haze

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Ever noticed the mist or fog inside an airplane cabin on a humid day? That's when the hot, muggy air from outside mixes with the cool air from the aircraft's air conditioning vents.

A couple weeks ago, TikTok user Savannah Gowarty posted a video of inflight mist and condensation on a domestic US flight. The video garnered over 13.1 million views, with amazed and confused commentators questioning what was going on.

Short answer: it’s a natural occurrence that usually only lasts a short while, and it’s nothing to worry about.

"According to a spokesperson from the Federal Aviation Administration (FAA) speaking to CNN Travel, on hot and humid days, the cold air from the plane's air conditioning system mixes with the warm, humid air inside the cabin. This causes the cabin air to cool down to the dew point, resulting in fog formation."

"The fog is usually temporary because the cooled air warms up quickly once it rises above the dew point."

Explanation:

Before a plane takes off, the cabin air is cooled either by an external ground unit or the aircraft's own Auxiliary Power Unit (APU), according to a spokesperson from the FAA.

Climate scientist Indrani Roy, who works at University College London, explains that both air conditioning and air humidification systems on airplanes provide cold air, usually much cooler than the ambient temperature. This cold air can temporarily lower the dew point of the aircraft cabin air enough to create fog.

Roy points out that the environment inside an airplane creates perfect conditions for condensation in the cabin. This is why cabin surfaces - and even people - might feel damp. Condensation occurs when water vapor in the air, which is "prone to sticking," comes into contact with any cooler solid surfaces. And there are plenty of solid surfaces inside an aircraft.

Roy explains that condensation is more likely to occur in the cold solid surface areas of the cabin. So, when flying back to New York on a 4-hour flight, being soaking wet and cold is definitely not the ideal situation. #flying #plane #vacation #pilot #fyp

Roy wants to reassure everyone that mist and condensation are nothing to worry about. On flights, humidity can create fog, but it is completely safe. However, passengers may feel uneasy, especially if they are experiencing it for the first time, according to US flight attendant Rich Henderson.

Henderson tells CNN Travel that passengers often mistake fog for smoke. He explains that a simple explanation usually calms their nerves, as most passengers do not get upset too often.

Passengers often get confused when they see condensation on the airplane windows. However, once you explain that it is simply the result of cold air from the aircraft's air conditioning system meeting the warm humid air inside the cabin, they usually understand quickly. Henderson also mentions that passengers usually find the humorous side of the situation.

“I usually make a joke that it’s just like we’re in an ‘80’s music video and that usually gets people laughing about it pretty quickly.”

In flight carry on bag cabinet, on board suitcase storage overhead bin in passenger cabin crew.

In flight carry on bag cabinet, on board suitcase storage overhead bin in passenger cabin crew.

coffeekai/iStockphoto/Getty Images

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Flight attendants are skilled at determining whether passengers prefer a detailed scientific explanation or a brief, humorous one. Henderson mentions that these interpersonal skills are not typically taught in training, but are quickly learned through daily interactions with people of various perspectives.

Passengers can feel anxious when they encounter something unfamiliar, according to Henderson. For example, unexplained noises or engine sounds can be the cause of this anxiety.

Henderson suggests that a simple explanation and a little joke can help ease the passengers' anxieties in such situations.

There's no need to worry about airplane fog - it's just an opportunity for you to channel your inner '80s pop star.

Don't fret about the fog messing up your hairdo, as the FAA spokesperson reassures that aircraft cabin fog typically clears up quickly.

When the colder air causes the cabin air temperature to drop to its dew point, fog may form. However, once the air warms back up above the dew point, the fog will disappear.

In most cases, the fog only lasts for a brief moment as it emerges from the vent, lingering for 1-2 seconds before dissipating.

Editor's P/S:

The article provides a comprehensive explanation of the natural occurrence of mist and condensation inside an airplane cabin on humid days. It highlights the role of the aircraft's air conditioning system in cooling the cabin air and the subsequent mixing with warm, humid air, resulting in fog formation. The article also addresses concerns raised by passengers and emphasizes that this phenomenon is temporary and harmless.

The article underscores the importance of effective communication by flight attendants in reassuring passengers and providing accurate information. It suggests that a combination of scientific explanations and humor can help alleviate any anxiety or confusion experienced by passengers. By understanding the underlying mechanisms behind cabin fog, passengers can appreciate it as a transient phenomenon and avoid unnecessary worry.