Continuous aldehydes monitoring in primary schools in France: Evaluation of emission sources and ventilation practices over 5 weeks

This paper presents a field campaign conducted in two French elementary schools for 5 weeks aiming at identifying effects of occupation and ventilation practices on indoor aldehyde concentrations and discriminating aldehyde emission from building materials and furniture. The investigated classrooms were first empty and not occupied whereas the furniture was added the following week. Normal school activities were restarted for the last three weeks under various ventilation practices. C2–C7 aldehydes concentrations were monitored with the conventional method based on DNPH derivatization using active sampling followed by off-line HPLC/UV analysis. Acetaldehyde (AA) and hexanal (HA) were the two main aldehydes present if formaldehyde is not considered. The weekly mean values of acetaldehyde concentrations were found in the range 9.5–13.1 μg m−3 (School 1), 9.4–17.6 μg m−3 (School 2) and equal to 5.3 μg m−3 (School 3). In Schools 2 and 3, weekly hexanal concentrations ranged between 3.3 and 5.4 μg m−3 but increased up to 40.1 μg m−3 in school 1 where painting work was performed during the week 2. Smaller amount of propionaldehyde (PA) and benzaldehyde (BA) were always detected, their weekly average concentrations being in the range 0.4–4.0 μg m−3 and 0.9–2.7 μg m−3 for PA and BA, respectively. The results supported by Student's tests show that building materials and furniture contribute to aldehyde emissions while ventilation significantly improves indoor air quality without being able to privilege one of the three ventilation scenarios tested.