A field measurement of housing environmental conditions was conducted in Beijing. Poor ventilation in homes could increase the risk of children's asthma and respiratory infections. DBP and DEHP in house dust were considered as a risk factor for childhood health. Cladosporium spp., Penicillium spp. and Aspergillus spp. accounted for about 90% of airborne fungi. Airborne fungal levels in about 70% of measured rooms exceeded 1000 cfu/m3 in summer.