Healthy schools: Standardisation of culturing methods for seeking airborne pathogens in bioaerosols emitted from human sources

Schools are one of the critical social infrastructures in a society, and children are particularly at risk of lung damage and infection caused by poor air quality. The issue of healthy schools is a global concern. In this paper, we highlight the importance of airborne transmission of microorganisms in schools and the impact on children's health and wider economic and social implications. We propose the concept of air hygiene; measuring and assessing the level of bioaerosols emitted from human sources (primarily respiratory) can serve as a guide to indicate overall air quality, associated with airborne infections. Current bioaerosol sampling in schools (if carried out) is based on the use of Trypticase Soy Agar that can indicate environmental sources of bioaerosols. We suggest that a more appropriate agar could be used for bioaerosols of human origin. It is critical to develop and standardise a simple and economic method that can be used in a range of schools and environments even if resources are limited to monitor the air hygiene. The use of blood agar and different samplings methods are reviewed, and the most appropriate method is proposed for further testing and validation in order to develop a global standard method.