Indoor PM2.5 concentrations and students' behavior in primary school classrooms.

It is important to understand changes in PM 2.5 concentrations to evaluate and control air pollution in the classroom. In this paper, the PM 2.5 concentrations in classrooms of a primary school in North China were studied, where the particulate matter, temperature and humidity were monitored continuously from February 2018 to February 2019. Student behavior has been recognized as an important influential factor of indoor air quality; however, modeling the relationship between student behavior and PM 2.5 concentrations in classrooms remains an unsolved problem. In this paper, a novel intelligent data-driven symbolic regression method is applied to model the relationships between various factors and PM 2.5 concentrations. The advantage of this method is that it can automatically distill knowledge from data and discover the structures and parameters of relationship models simultaneously. By considering the annual schedules and daily behavior, a symbolic regression model is incorporated with mass conservation to describe the change in PM 2.5 concentrations caused by student behaviors. The experimental results show that outdoor PM 2.5 concentrations can influence the concentrations of indoor PM 2.5 through meteorological variations. Moreover, student behaviors play an important role and can lead to rapid changes in indoor PM 2.5 over a short timeframe. This paper provides a solid theoretical analysis of the relationship between indoor PM 2.5 concentrations and student behaviors in classrooms. The numerical models proposed by this research can assist in the analysis of PM 2.5 concentrations and the improvement of air quality in the classroom. • A student source strength model in the classroom is proposed by combining symbolic regression and conservation of mass. • PM2.5 concentrations in the classroom are affected by outdoor PM2.5, meteorological variations, and student behaviors. • A new method is proposed to calculate the changes of PM2.5 concentrations in the classroom. [ABSTRACT FROM AUTHOR]