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Tires might seem like one of the simplest parts of a motor vehicle, but many drivers put their tires at risk by filling them with compressed air. The science is clear: compressed air introduces water vapor and contaminants into tires, which can damage tires and cause major safety problems. There is a solution to the pitfalls of compressed air: filling tires with nitrogen.

The Dangers of Compressed Air

An air compressor is simply that: a machine that compresses atmospheric air and forces it into a container, e.g. a tire. The compressed air carries with it any contaminants present in the atmosphere and/or the compressor, including water vapor and particulates. Once inside the tire, these contaminants cause corrosion which can damage the tire and shorten its lifespan.

In addition to damage inside the tire, compressed air can also increase wear and tear on the outside of your tires. Compared with nitrogen, compressed air leaks from tires significantly faster, which can cause dangerous under-inflation.

Under-inflation is a major problem. In a 2016 national survey, 42 percent of drivers admitted they rarely check their tire pressure. The National Highway Traffic Safety Administration reports that tires under-inflated by more than 25 percent are three times more likely to be involved in an accident. In fact, over 650 fatalities each year are caused by under-inflated tires.

Contaminants in Compressed Air

Compressed air isn’t the same as atmospheric air. It contains several contaminants, which can compromise the tires:

  • Oil: Compressor machines may pump liquid, aerosol, or vapor oil into tires, particularly due to oil lubrication or improper maintenance.


  • Particles: Compressed air machines can pull in particulate matter, including dirt, sand, soot, salt, and more. If the compressor’s intake is not properly placed, these particles enter the tire and cause harm.


  • Microorganisms: Atmospheric air contains up to 100 million microorganisms per cubic meter. Compressed air contains oxygen and water vapor, which allows for the growth of bacteria, spores, and mold inside the tires.

Government regulations monitor the use of compressed air in the food industry to ensure food safety. Unfortunately, some gas stations and mechanics don’t properly maintain their compressed air systems, which can increase the risk of contaminants and water vapor.

Water Vapor: The Number One Danger of Compressed Air

When drivers fill their tires with compressed air, they also introduce water vapor into the tires. Popular Mechanics explains that water in tires “causes more of a pressure change with temperature swings . . . it also promotes corrosion of the steel or aluminum rim.”

Humidity in the intake air can easily introduce water into your tires. And once the water is inside the tire, it begins breaking down the metal parts of the tire and damaging the rubber.

On top of that, water vapor makes it difficult to keep your tires at the correct air pressure. As your tires heat up and cool down, water vapor expands and contracts, which can create under-inflation or even over-inflation problems. This can decrease handling and increase the risk of a blowout.

Safety Problems with Compressed Air

Compressed air can lead to major safety problems, including:


  • Corrosion: Oxygen breaks down metal through a process known as oxidation. Similarly, water vapor corrodes steel and aluminum. Both can permanently damage tires, meaning drivers have to replace their tires more frequently and risk tire failure.



  • Increased wear and tear: Tires that are under-inflated wear down faster than properly inflated tires. Because nitrogen has a larger molecular size than oxygen, it doesn’t leak from tires as quickly, keeping tires at the correct pressure and slowing wear and tear.



  • Blowouts: Corrosion and worn tires, as well as under-inflation, can all lead to blowouts. During a blowout, drivers may lose control of their vehicle, which can put people’s lives at risk.


An Alternative: Nitrogen Inertion

For years, compressed air was the only option for filling car tires. Today, drivers benefit from a new alternative to compressed air: using nitrogen to inflate car tires.

Nitrogen inertion eliminates many of the problems caused by compressed air. First, nitrogen gas does not contain water vapor or oxygen. Without these ingredients, tires are safe from oxidation and microbial growth.And because tires filled with nitrogen stay at the correct pressure longer, drivers who rarely check their tire pressure face less risk of dangerously under-inflated tires. Tire-related issues cause nearly 200,000 accidents each year, along with 33,000 injuries. By inflating tires with nitrogen, drivers protect their tires and benefit from a safer drive.

Post Author: Genevieve Carlton Ph.D.

Ph.D. - Research Historian from Northwestern University. A writer and researcher she has published pieces for Ranker, Stacker and Atlas Obscura. She has published a nonfiction history book with the University of Chicago Press and a number of scholarly articles with top journals.

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