Table I.

School Environmental Intervention Studies

Study	Population	Design	Population/School Size	Intervention	Effectiveness of Intervention
Pilotto et al.76 (2004)	Children with asthma from primary schools (mean age 8–9 y; Australia)	Randomized control trial	18 schools, 10 control and 8 intervention schools 118 children, intervention group 45, control group 73	Replacement flued gas or electric heaters in schools	Reduction in NO2 exposure Reduction in asthma symptoms
Jhun et al.77 (2017)	Children with asthma (aged 6–10 y; US)	Randomized control trial (Pilot Study)	3 schools, 9 control and 9 intervention classrooms 25 children, intervention group 12, control group 13	Classroom based HEPA air cleaner intervention	Reductions in PM2.5 and BC Modest improvement in peak flow, no significant changes in FEV1 and asthma symptoms
Bernstein et al.78 (2005)	US	Randomized control trial (Pilot Study)	Day care A: 8 rooms Day care B: 6 rooms Intervention installed in half the rooms of each day care	Dehumidification plus day care room based HEPA air cleaner	Lower average dew point from baseline for both day care A and B Reduction in fungal spore counts for day care A only
Lignell et al.79 (2007)	Children (aged 7–12 y; Finland)	Longitudinal intervention study	1 Moisture damaged school 1 Non-damaged school Over 2,400 children returned surveys	Damaged school renovated for all identified problems, mechanical exhaust and supply air ventilation system installed	50% reduction in fungal concentrations Modest reduction in respiratory symptoms
Meklin et al.80 (2005)	Children (aged 6–17 y, Finland)	Longitudinal intervention study	2 Moisture damaged schools 2 Non-damaged schools Over 1,300 children returned surveys	Damaged schools thoroughly cleaned, repaired, and renovated, mechanical exhaust and supply ventilation system installed	Normalization of indoor air fungal concentrations Reduction in respiratory and other symptoms
Karlsson et al.81 (2004)	Sweden	Intervention study	3 schools, 6 classrooms in total, 3 control and 3 intervention classrooms from each school	1 class of children with no pets, 2 classes of children who changed into special school clothing upon arrival	4-fold to 6-fold lower airborne cat allergen levels in intervention classes compared with control classes

Abbreviations: NO₂, nitrogen dioxide; HEPA, high efficiency particulate arrestance; PM_2.5, particulate matter 2.5; BC, black carbon; FEV₁, forced expiratory volume in 1 second; US, United States