Aim: To evaluate the association between the indoor air quality in Porto schools and the prevalence of allergic and respiratory symptoms in adolescents.
Material and methods: Temperature, relative humidity, carbon dioxide (CO2) and volatile organic compound (VOC) concentrations were evaluated in nine Porto schools. Questionnaires were distributed to 9 classes of 7th , 8th and 9th year students in each school, total 1607 adolescents, with a mean age of 14.0 years (standard deviation=0.3). Information was collected on participants' socio-demographic and social characteristics, behaviour, and housing conditions. The International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire was used to evaluate respiratory symptoms.
Results: 5.8% of participants stated they had had asthma, 9.2% wheezing, 22.0% sneezing and 6.6% itchy rash In the 12 months preceding the evaluation. After adjustment for parental educational attainment level, CO2 > 2100 ppm values were associated with exercise- induced wheeze [OR=1.86 (95%CI:1.20-2.89)] and night cough [OR=1.40 (4.20-2.89)]. We observed an increasing odds ratio in wheezing symptoms over the last 12 months, in asthma 'at some point' and asthma over the last 12 months, and night cough at schools with higher VOC values. The association was not statistically significant, however.
Conclusion: Lower indicators of indoor air quality, particularly CO2, were associated with a greater respiratory symptomatology.