Nitrogen is not used to power air weapons, I think you may be getting confused with CO2 which is a common air weapon propellant:
Correction. Nitrogen IS used to power airguns and has been for some time. Just look at the new "NITRO Piston" air systems produced for Crosman and Benjamin.
Nitro Systems, unlike spring systems, can be left cocked over a long period of time with no effect on the firing system they also do not cause spring wobble when fired. The gas is considered very stable.
Air you asking about airguns as in Pneumatic tools, or as in shooting.
There are websites specifically for the sale of guns, but airguns can also be found on websites like Amazon and eBay for sale. Gunmart is a popular website to buy airguns from.
Then Nitrogen you inhale has no use. But nitrogen, from other sources, such as food, helps sperm production.
You don't use headphones with an air pistol. Headphones are used for communication devices. If anything you would use ear protection or noise protection or hearing muffs. In most cases it is not necessary to use them with most small bore airguns. But there are a few high powered air guns and I do mean high powered airguns that it is best to use them. Most all of these airguns are in the PCP (PreCharged Pneumatic) airgun class that use very high power systems to fire the pellet and are very loud. These are not commonly found in general use by shooters. However it never hurts to use some sort of ear protection
Plants use nitrogen a N- and air has N2. Nitrogen fixation changes nitrogen into a form that plants can use.
I suggest you look online for "Airgun Repair" and select a shop that repairs airguns. There are shop that make a living repairing airguns. Pyramydair also has repaired airguns in the past and may still be doing so.
Nitrogen is very important in fertilisers.
Airguns are unregulated in the United States. In several other countries a license is required for airguns over a certain energy level.
I'm not sure if this is what you are looking for, but Airforce Airguns uses a squirrel in their adds. He's wearing a helmet and holding an acorn with the words "Protect your nuts" below him. You can find him in almost every AirForce airgun add. Airforce Airguns makes one of the most powerful airguns around. They are in the PCP class of airguns. They are adaptable to 12 different barrels.
During nitrogen fixation, nitrogen gas is converted into ammonia or other forms of usable nitrogen by nitrogen-fixing bacteria. This process is important because plants and other organisms cannot use atmospheric nitrogen directly in this form.
Grass and plants use nitrogen to grow.
because most of our atmosphere has nitrogen in it