Students practice during a sports class at Beijing Fengtai No 2 High School on Monday, when those in their last year of high school returned to classrooms in Beijing. (Photo: China Daily)

On April 24, a middle school student surnamed Li in Zhoukou, Central China's Henan province died after running in a sports class wearing a face mask. Two other middle school students, one in Hunan and one in Zhejiang province, died in similar situations.

There has been as yet no official medical conclusion that links their deaths with the wearing of face masks, but medical experts have said that wearing masks does increase the risks when doing sport because it limits the exchange of respiratory gases.

That in turn raises a new question: As the pressure of imported COVID-19 cases is still heavy and many schools have already resumed classes, how to best protect pupils' health? Especially, as the days are getting hotter with summer arriving, face masks might bring people more inconvenience, if not pose a risk in certain situations. There must be clear advice on their use.

On Friday, the National Health Commission and the Ministry of Education jointly issued a guiding document that requires pupils to take a medical mask with them, but those in low-risk regions do not need to wear them on campus.

Shanghai authorities also confirmed that students could go without masks if they stay outdoors and do not have close contact with each other. These are good moves because they take up the responsibility of letting people take off their masks, which is important.

But there are other prevention and control measures that need clarification. For example, many canteens, of schools and companies alike, ask diners to dine at different times so as to avoid having too many people inside the dining hall at one time. Should that continue? Many parents stay at the gate of kindergartens and primary schools at the end of the day to pick up their children. Should that be prevented? Some experts have advised suspending or stopping the practice of eye exercises in schools to avoid the hands touching the eye. Is that proposal reasonable?

The education authorities should consider these questions and provide answers, so that pupils, their parents and schools know what to do.

Besides, for lack of a national standard for children's face masks, many parents just choose N95 for their children, which might be too airtight and curb air exchange. It is time for education and health authorities to make a standard for parents to follow.