Electret-containing filter media

摘要: Filter media, such as electret-containing filtration media for filtering gas streams (e.g., air), are described herein. In some embodiments, the filter may be designed to have desirable properties stable efficiency over lifetime of increased normalized gamma, relatively low pressure drop (i.e. resistance), and/or basis weight. certain a composite two or more types fiber layers where each layer enhance its function without substantially negatively impacting performance another media. For example, one weight high air permeability, and throughout media's lifetime.