Analysis of indoor and outdoor PM2.5 mass concentration and influencing factors of a kindergarten in Nanjing

Measures the mass concentration of indoor and outdoor PM2.5 of a kindergarten during April 2015 to December 2015 (one week per month, excluding July and August). The results show that the outdoor and indoor median PM2.5 mass concentrations are 60.6 μg/m3 and 32.5 μg/m3, respectively. The correlation coefficient between indoor and outdoor PM2.5 reaches 0.74, 52% of the outdoor PM2.5 enters into the interior through the building envelope during the measurement period, and 55% of the indoor PM2.5 concentration variation is caused by outdoor particle source. The mean value of hourly I/O is 0.69, and the range is 0.1~5.46. The I/O value is influenced by outdoor PM2.5 mass concentration, it decreases with an increase of outdoor PM2.5 mass concentration, when outdoor PM2.5 concentration is high, I/O decreases with air change rate decreasing and vice versa, the outdoor relative humidity has a positive correlation with varying pattern of indoor and outdoor PM2.5 mass concentration, the wind speed has a negative correlation with indoor and outdoor PM2.5 concentration, and the outdoor air temperature is not significantly correlated with indoor and outdoor PM2.5 but is positively correlated with I/O.