Air pollution and the exposure of schoolchildren

According to the World Health Organization (WHO), any physical, chemical or biological substance that alters the natural properties of the atmosphere is classified as an air pollutant. The main air pollutants that have a negative impact on health are particulate matter, carbon monoxide, ozone, nitrogen dioxide and sulphur dioxide. Since children are considered to be more sensitive to the environment and spend a large part of their day at school during school hours, environmental conditions and the implementation of air quality management in schools are of particular importance.

Most school classrooms worldwide are naturally ventilated. If there are no significant sources of air pollutants indoors, students are exposed to similar pollutant concentrations in the indoor and outdoor air.

As air quality affects human health and the ability to perceive and concentrate, it is extremely important to raise public awareness of air quality while developing strategies for indoor and outdoor air quality management. These strategies are an important basis for designing health-promoting and cost-effective school campuses, buildings and classrooms. In addition, preventive measures are strongly recommended to reduce children's exposure to air pollutants at school, for example by monitoring sources of air pollution, ventilation activity and the exchange of outdoor and indoor air in the school environment.

Sources of air pollutants in schools

Indoor sources of air pollution are just as important as known outdoor sources such as road traffic. In developed countries, common sources of air pollution in schools include dust, classroom activities such as printing and painting, cleaning products, heating, pesticides and mold. The main sources of outdoor air pollution are local traffic, including school buses and public transportation. Activities related to school operations also play a role, such as maintenance or kitchen work. 

The exposure of school children

The main factors determining children's exposure to air pollution are school and local characteristics, including local topography and traffic conditions. Urban schools are more exposed to air pollution than those in rural areas with little traffic.

The topography of the school grounds, structural obstacles around the school site and prevailing wind conditions affect the transport and distribution of air pollution and consequently influence the respective exposure of students. The exposure of children in classrooms and micro-environments inside the school building is more complicated than outside. Indoor exposure in schools is determined by the classroom and indoor activities, including construction and insulation materials, the number of occupants, room size, classroom design (e.g. wall coverings, flooring and furniture) and the air exchange rate. Indoor pollution levels can be changed by improving the building and ventilation concept. This includes controlled air exchange and appropriate building insulation.

Health concerns

Recent studies on the relationship between children's health and air quality have shown that poor air quality was associated with more frequent asthma and rhinitis symptoms, and that children suffering from allergies are at higher risk.

• Mazaheri, M., Clifford, S., Jayaratne, R., Mokhtar, M., Fuoco, F., Buonanno, G., Morawska, L., 2014. School children’s personal exposure to ultrafine particles in the urban environment. Environmental Science & Technology 48, 113-120.
• Sousa, S.I.V., Ferraz, C., Alvim-Ferraz, M.C.M., Vaz, L.G., Marques, A.J., Martins, F.G., 2012. Indoor air pollution on nurseries and primary schools: impact on childhood asthma – study protocol. BMC Public Health 12, 435.
• Annesi-Maesano, I., Hulin, M., Lavaud, F., Raherison, C., Kopferschmitt, C., de Blay, F., Charpin, D.A., Denis, C., 2012. Poor air quality in classrooms related to asthma and rhinitis in primary schoolchildren of the french 6 cities study. Thorax 67, 682-688.