Ubiquity

As the swine flu outbreak deepens, panicked citizens of North America are donning face masks. In Mexico City’s downtown square, the Zócalo, for example, the army handed out face masks, and customs officials on U.S. borders are wearing protective personal gear, such as gloves and masks. But do surgical masks offer effective protection against viruses? In 2003, Jon Cohen wrote that the SARS virus, which is just 100 nanometers in size, can easily pass through such barriers. And there’s every reason to believe that swine flu, at 80 to 120 nanometers, can, too. From: Do Surgical Masks Stop Swine Flu? Probably not. (Slate)

Wearing one is at least reassuring. Seeing everybody else wearing one (as the newswires stockpile examples) is not.

(image: Daniel Aguilar/Reuters. Mexico City April 29, 2009)