It is far worse than "unhealthy." It can be DEADLY. Children, especially young children have lower oxygen reserves than adults. Most young children are nose breathers. Mask wearing decreases oxygen and can lead to respiratory acidosis and respiratory arrest. Lower oxygen concentations in the body adversely effects the immune system making children MORE vulnerable to illness. The ability to concentrate and learn are lowered. The psychological effects are very damaging as well. Children touch those already filthy and ineffective masks thousands of times a day adding layers of bacteria that are inhaled with each breath. Masks are ineffective and unnecessary and NOBODY should be wearing them. The most effective way to prevent disease is to WASH HANDS!