CDC Interim Recommendations for Facemask and Respirator Use to Reduce 2009 Influenza A (H1N1) Virus Transmission
Information on the effectiveness of facemasks and respirators for decreasing the risk of influenza infection in community settings is extremely limited. Thus, it is difficult to assess their potential effectiveness in decreasing the risk of 2009 influenza A (H1N1) virus transmission in these settings. In the absence of clear scientific data, the interim recommendations below have been developed on the basis of public health judgment, the historical use of facemasks and respirators in other settings for preventing transmission of influenza and other respiratory viruses, and on current information on the spread and severity of the 2009 influenza A (H1N1) virus. Read the rest of the article
CDC approved N95 face masks
The N95 respirator is the most common of the seven types of particulate filtering facepiece respirators. This product filters at least 95% of airborne particles but is not resistant to oil. This is the rating that is recommended by the Centers for Disease Control and Prevention to be used to help protect against airborne viruses. Below is a link to the NIOSH (National Institute of Occupational Safety and Health) website which lists N95 NIOSH approved face masks. You should at least consult this list before purchasing any face masks online or offline.
NIOSH Approved N95 face masks