[Indoor Formaldehyde and Benzene Series in Shanghai Residences and Their Associations with Building Characteristics...

From March 2013 to December 2014, we on-site inspected indoor concentrations of formaldehyde and a benzene series in 454 children's bedrooms that were decorated earlier than one year before our inspection. Large differences existed in the formaldehyde and benzene-series concentrations among individual bedrooms. Bedrooms that were inspected in winter had significantly higher concentration of formaldehyde than bedrooms that were inspected in other seasons (P<0.001), but the benzene-series concentration had no significant seasonal difference. Among bedrooms that were inspected in spring, those using different materials as wall coverings had significant differences in concentrations of the benzene series. Among bedrooms that were inspected in summer, those using different materials as floor coverings had significant differences in concentrations of the benzene series (P<0.01). Among bedrooms that were inspected in autumn, those with>5 household bonsais had significantly higher concentrations of formaldehyde than other bedrooms did. Among bedrooms that were inspected in winter, those with frequent use of air humidifiers and those in which pets were kept had significantly higher concentrations of the benzene series than other bedrooms did (P<0.05). These results indicate that, after a long time since decoration, the types of household wall and floor covering materials still have certain relationships with indoor benzene-series levels and, compared to decoration materials, household ventilation perhaps has greater effect on indoor formaldehyde levels. The indoor benzene-series level perhaps has associations with indoor humidity level and the keeping of pets in households. Household bonsaies may have limited effect on indoor formaldehyde and benzene-series levels in residences that were decorated a long time ago.