Scared to leave the house during flu season? Surgical masks, unfortunately, won't protect you from the germs circulating around.
Surgical masks aren't designed to protect you breathing in germs; they're designed to protect those who wear them from spreading germs, by blocking those droplets you shoot out when you sneeze or cough. Surgical masks also divert airflow so that you don't end up breathing directly on the people you're talking to.
The air we breathe in comes from all directions, while the air we exhale is more directed. So for a mask to filter the air you're inhaling, it would need to form a seal around your mouth and nose, and surgical masks aren't designed to do that. Instead, doctors protect themselves from airborne infections by wearing special snug-fitting respiratory masks, which filter out about 95 percent of a given concentration of particles.
Keep in mind that most colds spread from mouth to hand, and hand to mouth. So while a mask might help somewhat, and also help keep you from touching your nose and mouth, the number one way to protect yourself from the common cold is to wash your hands with soap and water.
"Masking a Cold" (New York Times)
"Do Masks Work When It Comes to Preventing the Spread of SARS?" (CNN)