Facemasks have been flying off the shelves at some of Beijing's pharmacies at 10 times the normal speed in recent days after the city was hit by two recent sand and dust storms.

A couple gets close despite their facemasks in the streets of Beijing. The city experienced its second sand storm on Monday. [China Daily]

Jinxiang, a leading pharmacy chain in the capital, is one of the places that has seen a dramatic increase in demand.

A middle-aged saleswoman at the North Third Ring Road outlet of Jinxiang told METRO they sold dozens on Monday morning.

"The disposable facemasks are selling better these days. They cost only 12 yuan for 20," she said. "The cotton ones cost 5 yuan each. Of course, they are more environment-friendly and more protective because they have about 16 layers of gauze, but it would be too much trouble to wash them after a day's use.

"Usually, people will not wear facemasks during spring time but, because the sandstorm hit the city at a later date this year, sales have been better than usual. All we have done this morning is sell facemasks."

At the Hedantang pharmacy in Chaoyang, the branch manager, surnamed Zhao, said facemasks were selling well.

"We have seen sales of facemasks double in our store. But it is very normal," said the manager.

"People walking by will simply enter the shop and buy one to shield them from the annoying sand. It is only for the sake of convenience."

Dr Richard Saint-Cyr, a family physician at the International Medical Center in Beijing, said the sand and dust storms need not pose a significant risk to people's health.

"A majority of the sand particles are big and they get filtered out by the body's natural systems," he said. "It may leave a gritty feeling in your mouth and nose, but a certain percentage of that is just coughed out. For most healthy people, it is just really annoying. It will make them cough and give them extra phlegm."

Saint-Cyr pointed out that sandstorms usually only happen a couple of times a year and said most people ignore them and carry on as usual. But he suggested it's best to wear masks and avoid outdoor activities if possible.

Beijing meteorological center said the sand and dust hit Yanqing county at 8 am Monday and spread to the whole city an hour later. The center said it is not likely that Beijing will see a full-out sandstorm in the coming week. However, people should be prepared for the possibility throughout April.

Primary schools and middle schools in Beijing cancelled outdoor activities, such as exercises between classes, and scrapped sports class on Monday.

Although the local education bureau did not send out a notice to schools, most elected to make such activities into indoor pursuits on Monday to protect the health of students.