The President of Arak University of Medical Sciences said: "Due to the cold temperature and insufficient air circulation, long-term presence of people in indoor environments can increase the chance of corona disease by up to 50%."

Dr. Seyed Mohammad Jamalian emphasized that the use of a mask alone can not provide 100% protection against the corona virus, because recently most patients with Covid 19 disease go to medical centers with their families, and all these are because of attending parties, celebrations, weddings. And different epochs.

He pointed out: At present, if people are present in a closed environment while using the mask for more than half an hour, with the presence of only one carrier, the possibility of infecting other people is more than 50% due to the lack of air circulation