IAQ Aspects of Daycare Centers: A Systematic Review of Exposure to Particular Matter

When an infant is born, he or she begins independently breathing for the first time, meaning that immediately his or her lungs start becoming a principal interface between the outside air and the organism being considerably and continuously influenced by the Indoor Air Quality (IAQ). Daycare centers (DCCs) or early life educational institutions, the first program for the social development of young children (generally aged 0-5 years old), are the most important place besides their home. Young children, one of the most vulnerable population groups, spend most of their time at DCCs (up to 10 hours per day, 5 days per week, mostly indoors). Therefore, creating a healthy indoor environment for infants is important in DCCs. As one of the most health-relevant indoor air pollutants, the focus of this research is on the Particulate Matter (PM) that should be well-thought-out in DCCs. Thus, to characterize the status of PM exposure level at the most recent daycare centers worldwide, this work evaluated 35 peer-reviewed articles (2010-2020) on children's environmental exposure to PM, and major emission sources. Details about exposure to PM10, PM2.5, PM1 at DCCs were presented, analyzed, and compared based on continents, countries, seasonal variations, and urbanization. Among the reviewed studies, a total of 754-early-life educational institutions were involved in the measurement of PM levels worldwide. Most of the children were exposed to inadequate environmental conditions at daycare centers around the world, especially in Asian countries. Adequate evidence supports the statement that young children enrolled in daycare centers in urban areas, particularly near busy roads, are exposed to more concentrations of PM. There is a good trend in increasing monitoring of PM levels across the countries, especially in Asian regions, but, still, more particulate matter characterization and standardization of sampling techniques are needed. More attention should be placed at indoor air quality (IAQ) within the young children’s breathing zone (e.g., sleeping micro-environment). There is a clear need to improve IAQ in daycare centers and to establish specific IAQ guidelines for exposure limits in these early-life educational environments.