Abstract: A closed loop air handling system for monitoring and cleaning air from corrosive contaminants. Commonly occurring corrosive elements found in air can react in combination together and with other environmental conditions to increase the propensity for corrosion to occur. The higher corrosive level of air can react with metals causing degradation, wear and often lead to premature failure. This is especially prevalent in environments using forced air convection for cooling, such as data centers. The electronic circuitry is especially vulnerable to such corrosion and requires an environmentally controlled atmosphere with mild corrosiveness for long term reliability. The invention involves circulating the air in a closed loop and monitors and adjusts parameters of active filtration and purification to minimize corrosive agents. The system maintains a milder corrosive environment and better accommodates the use of “free cooling” from outside air for improved energy efficiency and lower carbon emissions.