Study On Indoor Air Quality In Tianjin Residential Buildings And Its Health Effects

Indoor environment has an important impact on human health.In China,outdoor air has bad quality.Outdoor PM2.5 enter indoor environment through ventilation and infiltration.On the other hand,with increased consumptions of new materials for indoor decorations and furtinures,volatile organic compounds become substantial indoor pollutants.In order to investigate indoor air quality in Chinese homes and its association with occupant's health,we conducted research in 32 households.Firstly,objective home measurement and subjective questionnaire survey were conducted in 32 Tianjin homes.In each season,environmental parameters were measured under closed conditions?i.e.,doors and windows were closed 12 hours before measurement?and normal conditions?i.e.,no intervention on doors and windows status?.Indoor environmental parameters measured were ventilation rate,air temperature,relative humidity,CO₂,formaldehyde,volatile organic compounds,PM2.5,ultrafine particulate,and ozone.In order to monitor the real-time changes of ventilation and pollutants in households,long-term on-line monitoring systems for indoor air quality were installed in 3 homes with natural ventilation system and 7 homes with mechanical ventilation system.Secondly,we analyzed the relationship of indoor pollutant concentrations with ventilation rates and sources.We found that the concentration of formaldehyde and volatile organic compounds were affected by indoor temperature and absolute humidity.Ventilation can effectively reduce the concentration of indoor pollutants.Especially in winter,operation of mechanical ventilation will improve indoor air quality,consequently the daily average concentrations of indoor PM2.5 and carbon dioxide were significantly lower than these in natural ventilated homes.At last,indoor air quality in Chinese homes and its association with occupant's health were analyzed using logistic regression.We found that exposure to indoor ultrafine particulate matter had significant negative effects on occupants'sick building syndrome symptoms.Higher ventilation rates had protective effects on people's health.In summary,our study shows that the insufficient indoor ventilation inTianjin residential buildings affects the indoor air quality and leads to the increment of indoor pollutant concentration,consequently affects the health of residents.