World's 1st ever asthma & allergy friendly® certified crib mattress. There is a 1 in 5 Chance Your Child Will Suffer From Asthma & Allergies. Dust mites, Pollen, & Pet Dander in your baby's sleep environment are contributors to these diseases. Pure Zees deals with these problems in an effective non-chemical way that unlike others is tested & proven. Our crib mattress is the world's first ever to be certified asthma & allergy friendly® by the Asthma & Allergy Foundation of America and Allergy Standards Ltd.