Clean air is vital to the teaching and learning environment, and children can be especially susceptible to air pollution, according to Ian Morton, director of C.A.N.DO, the environmental health program of The Lung Association, in Toronto. "Poor school air quality can have a number of critical effects, it can cause students to suffer short and long term health problems and reduce the productivity of students, teachers and staff through discomfort, sickness and absenteeism.

Children with asthma, who represent between five and ten percent of the school population, are particularly vulnerable to indoor air problems.