Evaluation of outdoor particle infiltration into classrooms considering air leakage and other building characteristics in korean schools

We analyzed the effects of air leakage and other building characteristics on outdoor particle penetration in classrooms. The building characteristics including air leakage of 12 Korean schools were investigated, and onsite measurements were conducted to estimate the outdoor particle infiltration. The correlations among variables associated with air leakage and building characteristics and outdoor particle infiltration were analyzed using the Pearson correlation analysis and linear regression. The effective leakage area (ELA) of classrooms varied highly from 340.8–1566.9 cm², and a significant disparity in the air leakage characteristics among the classrooms appeared. The results of onsite measurement revealed that the average ELA was larger in the corridor side with an ELA_{corridor-side} of 264.7 cm² than in the outdoor side (ELA_outdoor-side of 93.1 cm² ). Results of correlation analysis indicated a high correlation (r = 0.68~0.78, p-value < 0.05) between the size resolved outdoor particle source (P × λ) and specific ELA. Particularly, a strong linear relation (R² = 0.69~0.71) with specific ELA_{corridor-side} was seen. Results suggest that cracks between windows and doors in the corridor side considerably affect outdoor particle penetration. These results indicate the importance of improving the airtightness of not only the building envelope but also the inter-zonal walls for effectively reducing the outdoor particle infiltration into classrooms.