Outdoor air pollution, meteorological conditions and indoor factors in dwellings in relation to sick building syndrome (SBS) among adults in China.

Indoor environment is associated with the sick building syndrome (SBS), but little is known about the contribution of outdoor air pollution and meteorological conditions to SBS. We studied associations between outdoor air pollution, meteorological parameters and selected indoor exposure and building characteristics at home and weekly SBS symptoms in a standardized questionnaire study among 3485 randomly selected adults in China. Outdoor factors included particulate matters with diameter <10μm (PM10), sulfur dioxide (SO2), nitrogen dioxide (NO2), outdoor temperature (T), relative air humidity (RH), and wind speed (WS) during last three months. Multiple logistic regression was applied calculating odds ratios (OR) with 95% confidence interval (95% CI). Asthma or allergic rhinitis (atopy) was associated with all types of SBS symptoms except fatigue. Indoor factors played a major role in SBS symptoms. Mold/dampness on the floor/ceiling was associated with fatigue OR=1.60 (1.11-2.30) and headache OR=1.80 (1.07-3.04). Moldy odor was associated with fatigue OR=1.59 (1.07-2.37) and dermal symptoms OR=1.91 (1.21-3.02). Window pane condensation in winter was associated with fatigue OR=1.73 (1.30-2.31) and throat symptoms OR=1.53 (1.01-2.31). Damp bed clothing was related with throat symptom OR=1.62 (1.09-2.40). Home redecoration was associated with fatigue OR=1.49 (1.07-2.06). Frequent window opening was associated with less nose symptoms OR=0.54 (0.36-0.82) and mechanical ventilation in the bathroom reduced dermal symptoms OR=0.66 (0.44-0.99). Females were more susceptible to redecoration and window pane condensation than men. No associations with SBS were observed for outdoor air pollutants or meteorological parameters in the final models combining indoor and outdoor factors, although SO2, T, and RH were associated with some SBS symptoms (fatigue, eyes and nose symptoms) in the separate outdoor models. In conclusion, indoor mold/dampness, air pollution from redecoration and poorer ventilation conditions in dwellings can be risk factors for SBS symptoms in an adult Chinese population, especially among females.