Face masks had no effect on social distancing in Amsterdam, Rotterdam

An experiment with mandatory face masks in crowded areas in Amsterdam and Rotterdam did not result in people adhering to social distancing worse or better. Areas in which masks were mandatory also did not become less crowded after the mask obligation was implemented. About half of people wore face masks in the designated areas, according to research by the Dutch study center for criminality and rule of law NSCR.

The researchers studied the face mask obligation and what effect it had based on surveillance camera footage, street observations by field workers, street interviews and talking to focus groups. The experiment happened in areas of Amsterdam and Rotterdam between August 5 and 31.

Street observations showed that 53 percent of people wore a face mask in the designated area in the first two weeks of the experiment. In the last two weeks, that increased to 70 percent. Surveillance cameras showed that in the first two weeks 36 percent of people wore a mask, and in the last two weeks 49 percent.

The researchers attribute the differences to the fact that street observations took place in all areas with mask obligations, and camera observations only in a sample of areas "We consider the street observations to be a better source for an answer to this question than the camera images," the researchers said. "However, the upward trend over time is comparable with the two measurement methods."

Both the focus groups and street observations showed that people were more likely to wear a face mask if an enforcer or host was nearby. The increase in mask wearers can therefore at least partly be explained by more enforcers on the street as the experiment continued.

The researchers found that of the people who wore masks, 67 wore the masks correctly - covering both the mouth and nose. Areas where masks were mandatory did not become less crowded after the implementation of the mask obligation. Comparable areas with no mask obligation also saw no change in how crowded they were.

People violated social distancing rules on a regular basis. But, as initial study also concluded, this had more to do with how crowded an area was than whether people were wearing a mask. People often failed to stay 1.5 meters apart in both areas were masks were obligated and comparable areas where they weren't.