New ventilation systems at select schools in Sweden - effects on asthma and exposure.

States that schools often have a low air change rate. The study attempted to find out if an improvement in school ventilation would lead to improved health in pupils. A questionnaire was set for 1476 primary and secondary school pupils in 39 schools. 100 classrooms were monitored. New ventilation systems were installed in 12% of the classrooms over the survey period, increasing air change rate and reducing relative humidity and occurrence of a number of airborne pollutants. The study found that reporting of asthmatic symptoms decreased in the schools with new ventilation systems.