The moisture content in the air affects the conductivity of certain insulating materials and their ability to hold static charge. The higher the relative humidity (>50%), the higher the conductivity of these materials. Conversely, the lower the humidity (<30%), the more insulative these materials become and the more charge they hold. Logically, it would follow that high humidity would be an effective means of controlling static. However, even under high relative humidity, unacceptable levels of static charge can be generated and remain for long periods of time. Additionally, high humidity can contribute to other problems including oxidation and soldering difficulties. Using high humidity as a means to control static charge is slow, uncomfortable, expensive, and often ineffective.