Study On Ventilation Rates In Residential Buildings And Its Associations With Health

Ventilation is an important method to eliminate indoor pollutions.In China,natural ventilation system is popular in residential buildings.Ventilation measurement is importance to study indoor air quality and occupants' health in residential buildings.Ventilation rates of 322 residential buildings in Tianjin were measured by using carbon dioxide produced by occupants as tracer gas.The study was performed from Sep.2013 to Jun.2015.In this study,associations between ventilation rate,IAQ and occupants' health were analyzed.A multiple zone model was developed to calculate ventilation rates.In the multiple zone model,the direct of airflow was simplified and ventilation rate of residential building was obtained.Ventilation rates calculated in multiple zone model were validated by comparing with CO₂ concentrations and ventilation rates calculated in single model.There was good agreement between calculated air change rate and the “true” values.The median value of ventilation rate in residential buildings was 0.72 h-1 and 0.59 h-1 in child's room.Ventilation rates measured in summer were significant higher than other seasons?P=0.000?.Ventilation rates in room which open windows were significantly higher than close windows?P=0.000?.The median value of ventilation rates in child's rooms with openning windows was 0.49 h-1,while it was 1.80 h-1 in rooms with closed windows.Occupant density may influence CO₂ concentrations indoors.Children with mothers whose education level was high may live in rooms with lower ventilation rate.There were significant assocaitions between ventilation rate,dampness and odors in residential buildings.Formaldehyde concentration was higher in rooms with low ventilation rate?P=0.016?.The adjusted odds ratio of lower ventilation rate in residential buildings for rhinitis ever among children was 2.51?95% CI: 1.14-5.03?,and 2.30?95% CI: 1.05-5.00?for rhinitis current.The adjusted odds ratio of higher CO₂ concentrations in residential buildings for rhinitis ever was 1.65?95% CI: 1.01-2.70?,and 9.90?95% CI: 1.91-51.27?for common cold infections >2 weeks.Lower ventilation rate was associated with higher complaints on SBS symptoms among parents in residential buildings.It indicated that ventilation rate in residential buildings in China was low,which may not remove indoor pollutants efficiently,consequently may influence occupants' health.