Characterization, Source Apportionment and Health Risk Assessment of PM2.5 for a Rural Classroom in the Amazon: A Case Study

Classrooms are microenvironments in which children and teenagers may be exposed to fine particulate matter (PM2.5). Iranduba is a rural city in the Amazon region close to many brick kilns and road with high traffic levels. In this study, indoor and outdoor PM2.5 levels were measured in a classroom in Iranduba, and the PM2.5 exposure effects on student’s health were calculated. High indoor PM2.5 concentrations and high indoor-to-outdoor ratio values indicated particle accumulation within the classroom. The high percentage of black carbon (10%) in the dry season revealed the influence of burning processes on PM2.5 composition. Se, S, and Pb had an enrichment factor > 5, indicating that there is an important source for these elements in the city. The positive matrix factorization (PMF) model indicated soil resuspension, burning processes and vehicular emissions as the main PM2.5 sources. The excess risk shows that our classroom occupants are expected to be 30% more likely to develop lung-cancer than a group exposed to a background level of PM2.5. Therefore, it is important to have an effective ventilation system in order to reduce the accumulation of pollutants within the classroom and also to control/decrease the emission of pollutants in the city.