We take in nitrogen with every breath. Air is composed of:

• 1% Water Vapor and Other Gases – Escapes up to 250 times faster than Nitrogen
• 21% Oxygen – Escapes 3-4 times faster than Nitrogen
• 78% Nitrogen – The largest molecule in
  air, dry, non-flammable.

Because of their large size, nitrogen molecules are the least permeable and stay in your tire longer.

It's not about the nitrogen. It's about reducing oxygen, water vapor and other gases.

By reducing the percentage of oxygen, water vapor and other gases in your tires from 22% to 7% or lower, your tires will maintain proper pressure longer than if you use “plain old air.” For example, with 95% nitrogen in your tires, they retain optimal pressure three to four times longer.

Proper tire pressure is a big deal.
Maintain it with nitrogen, and you'll see
these three primary benefits:

• Increased Fuel Efficiency – Correct tire pressure keeps the manufacturer's recommended “contact patch” on the road. This lessens the rolling resistance and maximizes fuel efficiency. Read On...
  
  
• Longer Tire Life – When it comes in contact with other materials, oxygen causes oxidation. Oxidation can make rubber brittle and cause it to lose tensile strength. In addition, at high temperatures and pressures, oxygen reacts and damages inner tire liners and belt packages; nitrogen does not. Read On...
  
  
• Increased Safety – Under-inflated tires cause 90% of blowouts. Nitrogen provides more reliable pressure for reduced blowout potential. Read On...

Other benefits:

• Improved TPMS Performance – If you have a new car, you likely are plagued by a flashing light telling you your tire pressure is low. For example, one woman's light was going off every four to five weeks. After inflating with nitrogen, her light didn't reappear for 53 weeks!
  
  
• More Predictable Pressure Fluctuation – NASCAR teams use nitrogen so they can more accurately predict tire pressure fluctuation. Regular compressed air can fluctuate considerably when water vapor is present. Read On...
  
  
• Longer Rim Life – Rim rust caused by condensation from water vapor and other gases can get caught in valves and create slow leaks in tires. Nitrogen is completely dry, so it eliminates the potential for condensation.

• Bridgestone/Firestone researchers say that 93-95% nitrogen is all you need. Read On...
  
  
• According to Ford Motor Co., there is no difference between 96% and 99% nitrogen purity. Read On...

Who Else Is Using Nitrogen?

• NASCAR - NASCAR teams use nitrogen because it allows them to more accurately predict tire pressure fluctuation. Nitrogen fluctuates with temperature change, but it does so less than when water vapor is present. Read On... In addition, higher nitrogen levels eliminate the explosive properties of oxygen (oxygen loses its explosive properties at around 9% or less) Read On... NASCAR uses bottled nitrogen for portability. The bottles are delivered to the track by Praxair. Read On...
  
  
• Commercial Airlines – The Federal Aviation Administration (FAA) requires nitrogen in all commercial aircraft tires to eliminate the potential for water vapor (inherent in normal compressed air) from freezing at high altitudes. In addition, aircraft manufacturers such as Boeing use nitrogen membranes in their On-Board Inert Gas Generation Systems (OBIGGS) to "top" fuel tanks with nitrogen - an inert gas that does not support combustion.
  
  
• U.S. Government – NASA and the U.S. military use nitrogen for many of the same reasons it used in commercial aircraft.
  
  
• Food Processors and Packagers – Oxygen hastens both the chemical breakdown and microbial spoilage of many foods. Think meat, potato chips, cookies, etc. To help preserve foods longer, processors and packagers often use modified atmosphere packaging (MAP) and controlled atmosphere packaging (CAP) that replaces some or all of the oxygen in the air inside the
  package with nitrogen.

How is nitrogen separated from other gases in air?

Membranes are the heart of any nitrogen system. Just like a tire, the membranes are permeable. When thousands of these permeable tubes are filled with air at high pressures, smaller molecules leak out while the larger nitrogen molecules travel through the tubes into a holding tank to fill your tires or
for other uses.