air
Oxygen gas is needed for iron to rust. When iron is exposed to oxygen and moisture in the air, a chemical reaction occurs that forms iron oxide, which is known as rust.
Oxygen is the only gas which rust the metals.
The oxygen gas in rust comes from the oxidation of iron when it reacts with oxygen in the air or water. This reaction forms iron oxide, commonly known as rust, and releases oxygen gas as a byproduct.
The saltwater air causes things to rust faster than non-saltwater air.
The gas that causes the biggest amount of air pollution has to be carbon dioxide. Due mainly to emissions from vehicles.
water. because of the moisture in air, items can rust just by being in the open.
Oxygen is the gas that causes iron to rust. When iron is in contact with oxygen and water, it forms iron oxide (rust) as a result of a chemical reaction. Candles burn due to the combustion of wax, which releases carbon dioxide and water vapor.
Salty air, high ratio of moisture and relatively low temperature causes iron to rust quicker.
I do not think that there is such an element. Oxygen is what reacts with iron to form rust, but it's a gas at room temperature. I may be wrong, though.
oxygen
The air is called flimolenium gas