The air could be polluted so I guess that polluted air could count as stale.
Stale air refers to air that has become stagnant and lacks freshness due to a lack of circulation or ventilation. It may contain higher levels of carbon dioxide, humidity, and pollutants that can impact air quality and contribute to discomfort or health issues. Renewing stale air by opening windows or using ventilation systems can improve indoor air quality and create a more comfortable environment.
The least expensive thing on earth is typically air, which is freely available in the atmosphere and does not have a monetary cost associated with it.
Ventilation in a room refers to the process of bringing in fresh air while expelling stale air. It helps to maintain indoor air quality by removing pollutants, odors, and excess moisture. Good ventilation is important for human health and comfort.
To stagnate (air or water) is to stop moving or circulating, becoming stale or foul from standing. When an air mass is concealed in one area for a extended period of time so it stagnates. When an enclosed are, such as a room, a basement, an attic, etc., receives no air circulation for a period of time, the air stagnates.
Air is considered abiotic, meaning that it does not contain any living organisms. It is composed of gases like nitrogen, oxygen, carbon dioxide, and others that are essential for supporting life, but the air itself is not considered alive.
A noun for damp, stale air is must or mustiness; the adjectives are musty or dank.
Humans
Stale air refers to air that has become stagnant and lacks freshness due to a lack of circulation or ventilation. It may contain higher levels of carbon dioxide, humidity, and pollutants that can impact air quality and contribute to discomfort or health issues. Renewing stale air by opening windows or using ventilation systems can improve indoor air quality and create a more comfortable environment.
The opposite of stale (food, air) would be fresh. The opposite of stale (tired, cliche) would be new, or original.
leave it exposed to the air, then after a few days (5 days or more) it will become stale.
Leave it unwrapped and exposed to the air ... if you want it to just get stale, the air should be relatively dry. If you want it to get moldy, the air should be moist, and you should keep it in a dark environment.
Exhaust fans work by pulling air from a room and expelling it outside, creating a flow of fresh air. This process helps remove stale air and odors by replacing them with cleaner air from outside.
An air tight container to keep it from going stale.
There are machines available to do this. The normal AC unit won't. If it's a big commercial installation, then the method to achieve this effect is to install a fresh air intake like a mitsubishi lossnay or Samsung equivalent alongside the AC. This has a heat exchanger for efficiency and brings fresh air in while extracting stale air. For a home, a twin duct system which bolts to the wall, with two holes drilled, one for fresh in and one for hot stale out does a similar thing. These are available from portable heating and cooling.
The air way stale and hot
The air way stale and hot
The air way stale and hot