ABSTRACT
Abstract Objectives: This review aimed to verify indoor and outdoor pollution, host and environmental microbiome, and the impact on the health of the pediatric population. Sources: A review of the literature, non-systematic, with the search for articles since 2001 in PubMed with the terms "pollution" AND "microbiome" AND "children's health" AND "COVID-19". Summary of the findings: Prevention of allergic diseases includes the following aspects: avoid cesarean delivery, the unnecessary overuse of antibiotics, air pollution, smoking in pregnancy and second-hand tobacco smoke, stimulate breastfeeding, soil connection, consume fresh fruits and vegetables, exercise and outdoor activities and animal contact. The children's microbiota richness and diversity decrease the risk of immune disbalance and allergic disease development. Conclusions: Lifestyle and exposure to pollutants, both biological and non-biological, modify the host and the environment microbiome provoking an immune disbalance with inflammatory consequences and development of allergic diseases.