Very volatile and volatile organic compounds (VVOCs/VOCs) and endotoxins in the indoor air of German schools and apartments (LUPE10)

People, including sensitive population groups such as children, spend over 90 % of their time indoors and are exposed to volatile and very volatile organic compounds (VOCs/VVOCs) and endotoxins. We measured 34 VVOCs, 69 VOCs, two organic acids, and endotoxins in the indoor air of 34 apartments and 27 classrooms using four different sampling techniques and analytical methods. Our study aimed to provide a comprehensive overview of a broad spectrum of substances rarely measured in indoor air. The following substance classes showed the highest sum medians in classrooms and apartments: alcohols 249 μg/m 3 and 518 μg/m 3 , aldehydes/acetone 81.6 μg/m 3 and 121 μg/m 3 and organic acids 61 μg/m 3 and 82 μg/m 3 . The individual substances with the highest medians were ethanol > acetic acid > acetone > decamethylcyclopentasiloxane > formaldehyde > acetaldehyde. The median of the total volatile organic compounds as the sum of the VOCs of C 6 -C 16 was 253 μg/m 3 (range: 638–3369 μg/m 3 ) in the apartments and 277 μg/m 3 (61–900 μg/m 3 ) in the classrooms. The median (95th percentile) levels of endotoxins in the classrooms and apartments were 5.8 EU/m 3 (15.3 EU/m 3 ) and 0.26 EU/m 3 (0.91 EU/m 3 ), respectively. Concentrations in apartments are significantly lower than in schools. According to current knowledge, levels pose no health risk. In addition to the classic VOCs, VVOCs should also be measured to a greater extent, as considerable exposure to substances from this group is expected indoors. These results underline the urgent need for further research to improve indoor air quality and protect public health. • 105 VVOC/VOC were analyzed in indoor air of 27 schools and 27 residences. • Airborne endotoxins were quantified in indoor particulate matter in the same buildings. • Concentrations of endotoxins in homes is significantly lower than in schools. • VVOCs have a large proportion of the content of volatile substances in indoor air. • Valid indoor air values are often lacking to assess the risks of VOCs and VVOCs.