Air monitoring
Monitoring was carried out in the living room of each dwelling visited. Air samples were collected continuously with passive air samplers (DSD-DNPH diffusion sampler, Supelco, Japan; VOC-SD diffusion sampler, Supelco, Japan) at 150 cm above the floor for 24 h.
At the same time, field blank samples were obtained, and temperature and relative humidity were measured.
Fifteen aldehydes and 39 VOCs were identified and quantified with the method described by Takigawa et al. (2004).