RESUMEN
Poor air quality in schools can affect children's desire and ability to concentrate and learn and may lead to increased rate of absenteeism. This study was carried out with the aim of characterizing and measuring indoor air quality in school buildings, measuring ventilation status and studying the impact of design and environmental parameters on some measured pollutant levels. The study was carried out in some primary schools of Alexandria City. All ventilation rate levels exceeded the ASHRAE standard of 15 cfm/pupil except for a few cases. Badly located and small window area led to air stagnation and low ventilation rates. Levels of TSP greatly exceeded a suggested daily guideline of 150 mug/m3. The highest average levels of TSP were found inside classrooms surrounded by unpaved playground and located near semi rural, commercial and heavy traffic areas, while lowest levels were in classrooms located next to residential areas. The average total bacteria were highest in winter. There was also a slight increase in respiratory symptoms and signs in winter. There was a significant positive correlation between average total, pathogenic and non-pathogenic bacteria with average TSP Levels, indoor CO2 levels and relative humidity; while a significant negative correlation was observed with ventilation rate and class volume occupied. The average attack rate of respiratory conditions was 1.96 episode per child. Running nose was the highest frequent symptom. Students of first grade had an incidence rate higher than that among fifth grade students