What causes the unusual smell on planes before takeoff?

The unusual smell is typically caused by de-icing fluid sprayed on the aircraft to remove ice and snow.

Is the smell from de-icing fluid harmful to passengers?

No, the de-icing fluid is non-toxic and not harmful to breathe in, though the smell can be strong.

What are the ingredients in airplane de-icing fluid?

Airplane de-icing fluid primarily contains glycols (like ethylene or propylene glycol) mixed with water.

Home / Science / Mysterious Plane Smell Explained: It's De-Icing Fluid!

Mysterious Plane Smell Explained: It's De-Icing Fluid!

23 Dec

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Summary

Unusual plane odors are often caused by de-icing fluid.
De-icing fluid contains glycols, similar to car windshield fluid.
The smell is harmless, though it can be strong for some.

Mysterious Plane Smell Explained: It's De-Icing Fluid!

Many travelers have noted a distinct smell, often described as sweet like maple syrup or pungent like onions, during airplane takeoffs on cold days. This mysterious odor has sparked numerous online discussions among passengers seeking an explanation. The unusual aroma is commonly attributed to the de-icing fluid used by ground crews.

According to instructor pilot Kevin Singh, the smell originates from heated de-icing fluid sprayed onto aircraft to remove ice and snow. This fluid contains glycols, similar to those found in car windshield de-icers, mixed with water to prevent ice buildup. The process is crucial for generating lift and ensuring flight safety, typically taking 10 to 20 minutes.

While the smell can be noticeable as ventilation systems draw in outside air, it is deemed non-toxic and harmless. Passengers may experience mild irritation, but modern aircraft filtration systems help quickly clear residual odors. The scent, though strong, poses no significant health risk to the vast majority of travelers.