PM 2.5 Filtration reusable facemask is a made of 3 layers high quality fabric that can filter the fine particulate matter in the air which is concern for people's health when levels in air are high. PM 2.5 are tiny particles in the air that reduce visibility and cause the air to appear hazy when levels are elevated. This face mask is a non-medical use but it can help people to protect from bacteri and viruses around us. Fabric used are oekotext and intertek certified for safer use.