With the ground-level ozone pollution problem increasingly prominent in recent years in China, it is particularly important in basic researches on ozone contamination characteristics. In this study, 13 cities in Beijing-Tianjin-Hebei (BTH) area were examined to determine the characteristics of surface ozone (O3) from 2015 to 2018. Due to the photochemical oxidation of ozone precursors (such as nitrogen oxides and carbon monoxide) along with the presence of sunlight and characteristics of local emission sources, the O3 and oxidant (OX) concentrations showed obvious seasonal variation and daily variation. It implicated that the O3 concentrations reached the maximum during summer. The concentrations of O3 were higher at daytime than those measured at nighttime. The ozone weekend effect was estimated by the difference and deviation, which exhibited that the difference between weekday and weekend were related to the concentrations of ozone precursors and PM, vehicle emissions, and solar radiation. Moreover, the O3 concentrations decreased with the increase of other air pollutants by correlation analysis. The ozone pollution was easily formed at light and moderate polluted periods when compared to other air quality levels.

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Adverse health effects related to accumulative cadmium (Cd) exposure have aroused widespread attention from the public in China. Knowledge on the relationships between Cd exposure and early renal effects is particularly limited for children, who are more susceptible to absorbing metals than adults. A typical Cd-polluted area of South China was selected to determine the Cd exposure and related early renal effects of the general population, including children. In total, 211 children and 806 adults were enrolled in the study. The urinary levels of Cd (U-Cd), β-microglobulin (U-BMG), retinol binding protein (U-RBP), and N-acetyl-β-D-glucosaminidase (U-NAG) were measured. The relationship between U-Cd and ranked indicators of early renal effects was examined by multiple regression analysis. The average U-Cd ranged from 7.01 μg/g creatinine (boys) to 13.55 μg/g creatinine (women) in the Cd-polluted areas. These values are much higher than those of the control group and those that have been reported by other countries. In agreement with previous studies, environmental Cd pollution resulted in elevated Cd accumulation in the bodies of children, and it increased the concentration of NAG in their urine. Similarly, environmental Cd pollution increased NAG and BMG in the urine of adults. Multivariate models showed that the urinary excretion of BMG, RBP, and NAG was positively associated with Cd levels in the urine of both children and adults. The reference thresholds of U-Cd in relation to elevated U-BMG, U-RBP, and U-NAG were higher in children than adults after standardization for other covariates. These results reinforce the need to control and regulate the sources of environmental Cd contamination and to promote more effective risk management measures, especially for vulnerable groups.

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