To study the association of indoor air quality and ventilation in Chinese homes with occupants' sick building syndrome (SBS) symptoms, we performed a study in 32 homes over four seasons in Tianjin, China. Measured indoor environmental parameters were ventilation rate, and concentrations of volatile organic compounds (VOCs), formaldehyde, PM2.5, ultrafine particle and ozone. Occupants reported any sick building syndrome symptoms for the previous three months. Ventilation rates at night in bedrooms were 0.35 h(-1), 0.78 h(-1), 0.37 h(-1) and 0.41 h(-1) in spring, summer, autumn and winter, respectively. A low ventilation rate at night (below the median value of 0.45 h(-1)) significantly increased the risk (adjusted odds ratio, aOR) of mucosal symptom to 2.65 (95% Confidence Interval (CI): 1.16-6.06). The aOR of ultrafine particle for mucosal symptom was 2.37 (95% CI:1.02-5.49) and for dermal symptoms 3.96 (95% CI:1.63-9.60). The aOR of ozone for dermal symptoms was 5.86 (95% CI: 1.19-28.99). Dry air perception that indicated a polluted indoor environment was a risk factor for SBS symptoms in Chinese homes. (C) 2019 Elsevier B.V. All rights reserved.