Well what you're suggesting is thermal control and absorption which is a similar, but different, beast than ice powers and fire powers. Ice powers suggest the creation or manipulation of water particles to an effect. The same for fire manipulation. Air is not combustible without a source of ignition and/or fuel and the presence of an oxidizer like oxygen. Oily rags can spontaneously combust since there is oil on the rag and the oil has a low combustion temperature. Ice works in a similar way, but needs water to condense to have any form. Considering the origin point of the cold is your character, he or she would freeze solid before the environment would. 

The power level of this ability relies solely on how much control your character has over things like origin point, area of effect, and your character's willingness to harm others to use it. They'd be a real detriment in a group battle without proper control. Usefulness in a solo fight also needs to consider the speed at which these transfers take place. An alien, fist, or bullet hurtling towards you doesn't stop just because it gets really cold really fast