ABSTRACT
Objective To study the pollution and source apportionment differences of different periods PM2.5 in the residential community of suburb in Tianjin City during heating and non-heating periods. Methods From 2015 to 2016, daytime and nighttime PM2.5 samples were collected at a community in the suburb of Tianjin. The mass concentration of PM2.5 samples and major chemical components in PM2.5, including metal elements, polycyclic aromatic hydrocarbons (PAHs) and inorganic water-soluble ions were monitored. Positive matrix factorization (PMF) model was used to apportion potential sources of metal elements, PAHs and inorganic water-soluble ions in daytime and nighttime PM2.5. Results In the heating period, the concentrations of some metal elements of suburban residential community were higher in the daytime than in the nighttime. In the non-heating period, the concentrations of some PAHs and inorganic water-soluble ions of suburban residential community were higher in the nighttime than in the daytime. Meanwhile, the concentrations of some metal elements were greater in the daytime than in the nighttime. When in heating period, the main source of PM2.5 in the suburban residential community was coal combustion during daytime and its source contribution rate was 50.1% while secondary aerosol and fuel combustion emissions of gasoline and diesel vehicles were main sources during nighttime and their source contribution rates were 41.0% and 35.9%. The principal source of daytime PM2.5 in the suburban residential community was indoor activity emissions during non-heating period, and secondary aerosol was main source during nighttime and their source contribution rates were 29.8% and 31.1%. Conclusions The pollution status of PM2.5 in residential communities of suburban is serious, and the source apportionment of day and night PM2.5 samples has different in different heating periods.
ABSTRACT
Objective To explore the effect of air pollution on children’s respiratory diseases in Tianjin, so as to provide reference for the prevention and control of diseases. Methods Conditional Logistic regression model of single pollutant and multiple pollutants was used to estimate the relationships between air pollutants concentration and children’s respiratory system diseases. Results Conditional Logistic regression model of single pollutant conditions showed that the excess risk (ER) effects and 95% CI of NO2, PM2.5, PM10 and CO appeared were 2.823%(2.581-3.065), 0.476%(0.382-0.569), 0.437%(0.368-0.506), 22.263%(15.449-29.478), respectively. Logistic regression analysis of multiple pollutants conditions showed that NO2 exposure had the greatest effect on children’s respiratory diseases in cold season, and the excess risk (ER) was 7.395%(6.595-8.202). Conclusion The elevated daily average concentration of NO2, PM10, PM2.5, and CO can increase the risk of children’s respiratory diseases.
ABSTRACT
Objective To investigate the effect of dietary nutrition on dental fluorosis degrees of school children in endemic fluorosis areas. Methods Two hundred and eight children aged 8 to 12 years were chosen using cluster random sampling method from a village of municipal suburban and a town of autonomous region, both with a history of serious endemic fluorosis. Morning urinary fluoride was measured by fluoride ion electrode. The Tooth Surface Index of Dean was applied to measure the severity of dental fluorosis. Food and nutrient intakes were analyzed according to the 3-day diet records and duplicate meals. Results The urinary fluoride concentration of the children in the town [(6.80±3.90)mg/L]was much higher than those in the village [(5.20±2.75)mg/L, t= 3.21, P < 0.01]. Dental fluorosis index of the children in the town was 1.9, higher than that of the village of 1.8 (H=10.266, P < 0.01). The town had more children with fluoride tooth degree higher than Ⅱ [63.3%(57/90)]than the village did[48.3% (57/118), χ2=4.633, P < 0.05]. A 3-days diet records showed that children in the village ate more protein, calcium, vitamin C and so on but less dietary fiber, vitamin E, magnesium than those in the town did(all P < 0.01). Duplicate meals revealed that children in the town had more daily intake of magnesium, lithium, lead and less cadmium than those of the village did(P < 0.01 or < 0.05). Children in the village had higher intake of fluoride[(2.24±1.18)mg/d]than those of the town [(1.78±0.06)mg/d, t = 4.21, P < 0.01]. Conclusions Healthy diet can reduce the incidence of dental fluorosis or mitigate the degree of the impairment. This study can provide scientific basis for the future control and elimination of endemic fluorosis.