From:  An expert position paper on environment, occupation and climate change effects on allergic respiratory diseases in Italy

 Effects of indoor air pollution on respiratory health of children and adolescents.

StudyPopulation/AreaIndoor exposureOutcomesEffect estimation
Simoni et al., 2010 [169]Italy, France, Denmark, Norway, and SwedenCO2 in the classroom
PM10 in classrooms
Dry cough, rhinitis, nasal patencyOR 2.99 (95% CI 1.65–5.44)
OR 2.07 (95% CI 1.14–3.73)
Reduced patency
Cibella et al., 2015 [168]303 adolescents (10–17 years), PalermoNO2 indoor (spring and winter)Asthma, respiratory symptoms, lung functionNO2 indoor > outdoor; elevated levels associated with current asthma, wheezing, and decreased respiratory function
Cilluffo et al., 2022 [60]179 asthmatic children (5–16 years), PalermoMaternal smoking during pregnancy, overcrowdingAsthma controlMaternal smoking (OR 3.82, 95% CI 1.11–13.06) and overcrowding (OR 3.38, 95% CI 1.29–8.81) associated with uncontrolled asthma
Sarno et al., 2025 [170]4,899 children (6–14 years), 23 EU countriesSchool indoor air quality, mould, environmental factorsAsthma, allergies, respiratory symptomsHigh geographical variability; more symptoms in Southern Europe; Important role of the indoor environment
Baloch et al., 2020 [171]5,175 children (6–14 years), 23 EU countries (including Italy)School indoor air quality: benzene, limonene, CO, radon, ozoneUpper airway symptomsOR 1.62 (95% CI 1.27–2.08)
OR 1.72 (95% CI 1.33–2.22)
OR 1.27 (95% CI 1.01–1.60)
OR 1.36 (95% CI 1.04–1.78)
OR 1.99 (95% CI 1.56–2.52)
Benzene, limonene, PM2.5, ozoneLower airway symptomsOR 1.73 (95% CI 1.30–2.31)
OR 1.40 (95% CI 1.05–1.88)
OR 1.32 (95% CI 1.00–1.75)
OR 2.24 (95% CI 1.69–2.97)
Baloch et al., 2025 [172]5,140 children (6–14 years), 22 EU countries (including Italy)High concentration of endotoxins in classroomsRunny nose, nasal obstruction, irritative cough, dry throat, breathing difficultyOR 1.30 (95% CI 1.13–1.49)
OR 1.23 (95% CI 1.07–1.41)
OR 1.19 (95% CI 1.02–1.38)
OR 1.19 (95% CI 1.01–1.41)
OR 1.30 (95% CI 1.02–1.64)
Moshammer et al., 2025 [173]4,581 children (6–14 years), 21 EU countries (including Italy)High concentration of endotoxins in classroomsLung functionFor most parameters of lung function, a linear decline was observed with increasing endotoxin levels, without a clear threshold effect

Upper airway symptoms: runny nose/nasal obstruction; lower airway symptoms: dry throat/sore throat/irritative cough/breathing difficulty. CI: confidence interval; CO: carbon monoxide; CO2: carbon dioxide; EU: European Union; NO2: nitrogen dioxide; OR: odds ratio; PM10: atmospheric particulate matter with a diameter ≤ 10 μm; PM2.5: atmospheric particulate matter with a diameter ≤ 2.5 μm.