The purpose of this study is to investigate allergic diseases related to allergy caused by the exposure to indoor and outdoor sources of air pollution in primary schools. The symptoms questionnaire of allergic diseases based on the International Study of Asthma and Allergies in Childhood (ISAAC) was completed by the participants. The past and present status of asthma, allergic rhinitis, eczema, and allergic conjunctivitis were investigated by providing a questionnaire to all the participating children. Questionnaires were sent to a total of 61,350 children from 438 primary schools. A total of 40,522 children responded to the questionnaire, which represents a 66.1% return rate. Volatile Organic Compounds (VOCs), $underline{A}$ldehydes, and Particulate Matter ($PM_{10}$) were measured and analyzed from October to December of 2006, in 82 primary schools. The final study population comprised 35,168 children with complete data which excluded incomplete questionnaire responded by 5,354 children. Based on the survey, the level of indoor air contamination did not appear to be high, but 27.2% of the schools evaluated had exceeded the $PM_{10}$ level specified by the school health guidelines ($100;{mu}g/m^3$). The overall mean concentration of formaldehyde was $22.07;{mu}g/m^3$ and 1.0% of schools (1 school) exceeded the $100;{mu}g/m^3$. Statistically significant relationships have been observed between indoor air quality and prevalence rate of allergic rhinitis and conjunctivitis of primary schools in Korea.