Due to the anthropogenic pollution, especially the environmental crisis caused by air pollutants, the development of air pollutant degradation photocatalyst has become one of the major directions to the crisis relief. Among them, titania (titanium dioxide, TiO2) family materials were extensively studied in the past two decades due to their strong activity in the photocatalytic reactions. However, TiO2 had a drawback of large bandgap which limited its applications, several modification techniques were hence developed to enhance its catalytic activity and light sensitivity. In recent years, other metal oxide based materials have been developed as replacements for TiO2 photocatalysts. In this review, background information and developments from pure TiO2 to chemically modified TiO2-based materials as photocatalysts were discussed in detail, which covered their basic properties and their role in the air pollutant removal. It also proposes to solve the shortcomings of TiO2 by developing other metal oxide-based materials and predict the future development of TiO2 materials in future environmental applications.

Neonicotinoid insecticides (NEOs) are emerging pesticides of concern due to their potential toxicity to non-target species (e.g., bees, fish and birds). China is an important producer and user of NEOs in the world. Studies on human exposure to NEOs in China are very limited. In this study, urinary levels of six NEOs, namely acetamiprid (ACE), clothianidin (CLO), dinotefuran (DIN), imidacloprid (IMI), thiacloprid (THD), and thiamethoxam (THM) were determined in 324 individuals from 13 cities in China. Across all sampling locations, total NEO concentrations (ΣNEOs; sum of six NEOs) were dominated by CLO (median: 0.24 ng/mL), IMI (0.21 ng/mL), THM (0.15 ng/mL) and DIN (0.14 ng/mL) collectively accounting for 98% of the concentrations. Urinary concentrations of each NEO varied depending on the sampling location with the median values ranged from 0.057 to 1.2 ng/mL for CLO, from 0.036 to 0.83 ng/mL for DIN, from 0.069 to 3.2 ng/mL for IMI, and from 0.062 to 0.45 ng/mL for THM. Sex-related differences in IMI, ACE and ΣNEOs concentrations were observed with males presenting significantly higher urinary levels than did females. All six NEOs were significantly positively correlated (r = 0.135 to 0.661, p < 0.05) with each other, suggesting that the exposure sources of NEOs are common or related. On the basis of urinary IMI levels, we calculated the median daily intake (DI; mean and range) of IMI to be 1.6 (4.1, <0.02-55) μg/day, or 0.034 (0.11, <0.0003-2.1) μg/kg bw/day. To our knowledge, this is the first study to document the ubiquitous occurrence of and human exposure to NEOs in China.

Bisphenol A (BPA) and its alternatives are suspected endocrine disruptors. However, prenatal exposure and transplacental transfer of bisphenols (BPs is still limited. Therefore, BPA and its six alternatives in maternal serum (MS), maternal urine (MU), cord serum (CS), and amniotic fluid (AF) samples collected from 106 maternal-fetal pairs in an e-waste dismantling site in Southern China were determined. Bisphenol AF (BPAF) and bisphenol S (BPS) were the dominant BPA alternatives observed in MS and CS, and the geometric mean (GM) concentration of BPAF (0.013 ng/mL in MS, 0.097 ng/mL in CS) and BPS (0.01 ng/mL in MS, 0.03 ng/mL in CS) in MS and CS was lower than that of BPA (0.5 ng/mL in MS, 1.2 ng/mL in CS). The ratios of BPA concentrations between MU and MS (MU:MS ratio) were over three times higher than those of AF and CS (AF:CS ratio), thereby suggesting low biotransformation/metabolism of BPA in fetuses. The placental transfer rates of BPs (i.e., CS:MS ratio) were compound-specific (BPAF 3.26, BPA 1.94, BPS 1.11). Results suggest that BPA and its alternatives can pass through the placental barrier. The placental transfer rates of BPs are positively related to molecular weight or log Kow values. This finding indicates that an active transport is responsible for the placental transfer of BPs.