Airsense

• Range: varies (typically 5 to 120 feet)
• Requires Line of Sight? No
• Requires Line of Effect? Yes
• Usable for Combat Targeting? Yes
• Bonus/Penalty vs. Stealth? Perception check with a +5 circumstance bonus
• Ignores Invisibility? Yes

Description: Airsense functions almost exactly like Tremorsense, except that it detects movement and displacement within the air, rather than vibrations through the ground. For the purposes of this sense, any gas is considered "air". As a result, airsense does not function underwater or in any other environment which lacks air. Any non-stealthed creature moving through air which is shared by the creature with airsense, and that is within range is detected. The creature with airsense must make a perception check to detect stealthed creatures within range, but gains a +5 circumstance bonus to its perception. The DC of the perception check is equal to the stealthing creature's stealth check result. Invisibility does not provide any benefits to stealth against creatures with airsense. Detected creatures do not have concealment.

Airsense does not require line of sight, but must trace line of effect through the same pocket of air (or other gaseous medium) as the creature with the sense. Spells such as Fog Cloud (Sorcerer/Wizard Spell), which interrupt line of sight, but not line of effect, are penetrated completely by airsense, since the fog is just another gas. Similarly, Wind Wall (Sorcerer/Wizard Spell) (or other sources of strong winds), or permeable walls or pillars, like Pillar of Thorns (Druid Spell) do not impede airsense in any way. Pillars of stone, fire, or any other non-gas element (fire is not a gas), as well as walls of force or prismatic energies, particularly if they block line of effect, block airsense.

Airsense is a fairly 'loose', vague sense, that does not allow the detecting creature to distinguish between friend or foe, nor does it provide enough detail to allow the detecting creature to attempt a lore check against an unfamiliar creature, or recognize previously encountered individuals. Airsense cannot be used to read anything, not even deeply carved inscriptions or large painted symbols.