Urban green spaces have the potential to mitigate and regulate atmospheric pollution. However, existing studies have primarily focused on the adsorption effect of different plants on atmospheric particulate matter (PM), whereas the effect of green space on PM has not been adequately addressed. In this study, the effect of different urban green space structures and configurations on PM was investigated through the 3D computational fluid dynamics (CFD) model ENVI-met by treating the green space as a whole based on field monitoring, and at the same time, the regulatory effect of green space on PM was examined by integrating information about the forest stand, PM concentration, and meteorological factors. The results show that the green space primarily affected wind speed but had no significant effect on relative humidity, temperature, or wind direction (P > 0.05). The PM concentration was significantly positively correlated with the relative humidity (P < 0.01), significantly negatively correlated with temperature (P < 0.05), but not significantly correlated with wind speed and direction (P > 0.05). Comparison with the measured values reveals that the ENVI-met model well reflected the differences in PM concentrations between different green spaces and the effect of green space on PM. In different green space structures, the uniform-type structure performed rather poorly at purifying PM, the concave-shaped structure performed the best, and the purifying effectiveness of the incremental-type and convex-shaped structure of green space was higher in the rear region than in the front region; in contrast, the degressional-type green space structure was prone to cause aggregation of the PM in the middle region. Broadleaf and broadleaf mixed forests had a better purifying effectiveness on PM than did coniferous forests, mixed coniferous forests, and coniferous broadleaf mixed forests. The above results are of great significance for urban planning and maximizing the use of urban green space resources.

The antibacterial agent norfloxacin (NOR) and sodium hypochlorite (NaClO), which are both widely used in marine culture, react with each other to form the halogenated disinfection byproducts (X-DBPs). The effects of the water characteristics and iodide concentration on the reaction kinetics were investigated. The results showed that the reaction rate of NOR with NaClO increases from 0.0586 min⁻¹ to 0.1075 min⁻¹ when the iodide concentration was changed from 0 μg⁻¹ to 50 μg⁻¹. This demonstrated the enhancement of NOR oxidation in the presence of iodide ions. Four novel iodinated DBPs (I-DBPs) were identified in the marine culture water. Iodine substitutions occurred at the C3 and C8 positions of NOR. The formation mechanisms of X-DBPs in the marine culture water were proposed based on the intermediate and final products. NOR may undergo a ring-opening reaction, a de-carbonyl reaction and substitution to form intermediates and finally generate the X-DBPs. Furthermore, the predicted logKOW and logBCF values of the I-DBPs were higher than that of the Br-DBPs and Cl-DBPs. The AOX concentration in the synthetic water samples decreased in the following order: seawater (8.49 mg L⁻¹) > marine culture water (4.05 mg L⁻¹) > fresh water (1.89 mg L⁻¹). The amount of AOX also increased with the increase in iodide concentration. These results indicated that the I-DBPs were more toxic than their brominated and chlorinated analogues.

The Madín Dam is a reservoir located in the municipalities of Naucalpan and Atizapán, in the metropolitan area adjacent to Mexico City. The reservoir supplies drinking water to nearby communities and provides an area for various recreational activities, including kayaking, sailing and carp fishing. Over time, the number of specimens of common carp has notably diminished in the reservoir, which receives direct domestic drainage from two towns as well as numerous neighborhoods along the Tlalnepantla River. Diverse studies have demonstrated that the pollutants in the water of the reservoir produce oxidative stress, genotoxicity and cytotoxicity in juvenile Cyprinus carpio, possibly explaining the reduction in the population of this species; however, it is necessary to assess whether these effects may also be occurring directly in the embryos. Hence, surface water samples were taken at five sites and pharmaceutical drugs, personal care products (especially sunscreens), organophosphate and organochlorine pesticides, and other persistent organic pollutants (e.g., polychlorinated biphenyls and polycyclic aromatic hydrocarbons) were identified. Embryos of C. carpio were exposed to the water samples to evaluate embryolethality, modifications in embryonic development, lipoperoxidation, the quantity of hydroperoxide and oxidized proteins, and antioxidant enzyme activity (superoxide dismutase, catalase and glutathione peroxidase). It was found that the polluted water of the Madín Dam gave rise to embryolethality, embryotoxicity, congenital abnormalities, and oxidative stress on the common carp embryos.

Secondary inorganic aerosols, including sulfate, nitrate, and ammonium contribute to a large extent to the severe haze pollution events in China. Understanding their formation mechanisms is critical for designing effective mitigation strategies to control haze pollution, especially as the role of nitrate seemed to become more important recently, especially in some megacities. In the present study, simultaneous observations were conducted in two megacities (Chengdu and Chongqing) in Sichuan Basin of southwest China, one of the regions suffering from severe aerosol pollution. One typical long-lasting pollution event in Chengdu and Chongqing was captured during wintertime from December 25, 2016 to January 5, 2017. The campaign-average of hourly concentrations of PM2.5, sulfate, and nitrate, measured by an Aerosol Analyzer (ZSF) were 101 ± 73.8 μg/m3, 15.9 ± 11.8 μg/m3, and 24.9 ± 20.6 μg/m3, respectively, in Chengdu, and were 87.7 ± 53.8 μg/m3, 19.7 ± 13.5 μg/m3, and 15.1 ± 10.1 μg/m3, respectively, in Chongqing. Nitrate contributed substantially to PM2.5 pollution when PM2.5 was lower than 150 μg/m3, largely due to the strong secondary transformation of NOX to nitrate during the occurrence of the pollution episode. Heterogeneous hydrolysis of N2O5 dominated nitrate formation during nighttime, while photochemical reactions and high-RH enhanced gas- to aqueous-phase dissolution of NH3 and HNO3 or cloud processes likely played important roles for nitrate formation during daytime. RH-dependent heterogeneous reactions contributed greatly to the formation of sulfate. NOX is confirmed to play an important role as an oxidant in accelerating the secondary transformation of SO2 to sulfate at high RH and low O3 levels under neutralization condition during heavy PM2.5 pollution episode. Results from this study identified the formation mechanism of nitrate, especially during the daytime, and addressed the importance of heterogeneous inorganic reactions in the formation of heavy aerosol pollution events.

Heavy metals and emerging engineered nanoparticles (ENPs) are two current environmental concerns that have attracted considerable attention. Cerium oxide nanoparticles (CeO₂NPs) are now used in a plethora of industrial products, while cadmium (Cd) is a great environmental concern because of its toxicity to animals and humans. Up to now, the interactions between heavy metals, nanoparticles and plants have not been extensively studied. The main objectives of this study were (i) to determine the synergistic effects of Cd and CeO₂NPs on the physiological parameters of Brassica and their accumulation in plant tissues and (ii) to explore the underlying physiological/phenotypical effects that drive these specific changes in plant accumulation using Artificial Neural Network (ANN) as an alternative methodology to modeling and simulating plant uptake of Ce and Cd. The combinations of three cadmium levels (0 [control] and 0.25 and 1 mg/kg of dry soil) and two CeO₂NPs concentrations (0 [control] and 500 mg/kg of dry soil) were investigated. The results showed high interactions of co-existing CeO₂NPs and Cd on plant uptake of these metal elements and their interactive effects on plant physiology. ANN also identified key physiological factors affecting plant uptake of co-occurring Cd and CeO₂NPs. Specifically, the results showed that root fresh weight and the net photosynthesis rate are parameters governing Ce uptake in plant leaves and roots while root fresh weight and Fᵥ/Fₘ ratio are parameters affecting Cd uptake in leaves and roots. Overall, ANN is a capable approach to model plant uptake of co-occurring CeO₂NPs and Cd.

Seasonal and diurnal variations of carbonyl compounds were investigated in the ambient air of a mountainous city in China, from September 2014 to July 2015. The most abundant carbonyl compounds are formaldehyde, acetaldehyde and acetone, propionaldehyde and methacryladehyde (MACR), which were all measured in most samples. The average concentrations of formaldehyde, acetaldehyde, acetone, propionaldehyde and MACR in the atmosphere in Changsha were broken down into each season: 6.57, 3.29, 3.66, 0.67 and 0.54 μg/m³ respectively during Spring, 14.09, 8.28, 9.02, 1.28 and 0.6 μg/m³, respectively during Summer, 9.24, 5.48, 8.62, 0.73 and 0.62 μg/m³, respectively during Autumn, and 5.88, 4.84, 7.84, 0.87 and 0.26 μg/m³ respectively during Winter. And majority of the species had higher concentration during noon, showing photochemical oxidation and human activities played an important role in diurnal variation. The highest average C1/C2 (formaldehyde/acetaldehyde) ratio was observed in summer (2.10) compared to those (1.33–2.03) in other seasons, implying the photochemical activities had a positive effect on increasing the ratio of C1/C2. In this study, the monthly concentration of formaldehyde produced from isoprene accounts for 4.8%–39.1% of formaldehyde in ambient air. Strong correlation among some carbonyl compounds means that they came from the same sources. Photochemical reaction was the main source of carbonyl compounds in summer and vehicular exhaust (gasoline and diesel engines) in winter. Changsha is not a completely urbanized city and it is rich in vegetation of broadleaf evergreen shrubs. Both atmospheric photochemical reactions and anthropogenic sources, including vehicular exhaust and industrial processes, dominate the levels of carbonyls. The ILTCR and HQ values of formaldehyde and acetaldehyde are 1.23E-04 and 1.34E-05, 2.80E-01 and 1.86E-01, respectively.

Indoor air pollution is associated with numerous adverse health outcomes. Air purifiers are widely used to reduce indoor air pollutants. Ionization air purifiers are becoming increasingly popular for their low power consumption and noise, yet its health effects remain unclear. This randomized, double-blind crossover study is conducted to explore the cardiorespiratory effects of ionization air purification among 44 children in Beijing. Real or sham purification was performed in classrooms for 5 weekdays. Size-fractionated particulate matter (PM), black carbon (BC), ozone (O₃), and negative air ions (NAI) were monitored, and cardiorespiratory functions were measured. Mixed-effect models were used to establish associations between exposures and health parameters. Real purification significantly decreased PM and BC, e.g. PM₀.₅, PM₂.₅, PM₁₀ and BC were decreased by 48%, 44%, 34% and 50%, respectively. O₃ levels were unchanged, while NAI was increased from 12 cm⁻³ to 12,997 cm⁻³. Real purification was associated with a 4.4% increase in forced exhaled volume in 1 s (FEV₁) and a 14.7% decrease in fractional exhaled nitrogen oxide (FeNO). However, heart rate variability (HRV) was altered negatively. Interaction effects of NAI and PM were observed only on HRV, and alterations in HRV were greater with high NAI. Ionization air purifier could bring substantial respiratory benefits, however, the potential negative effects on HRV need further investigation.

Due to the lack of substantial and reliable evidence on the relationship between prenatal cadmium (Cd) exposure and cognitive development of offspring, we conducted the present systematic review. Leading electronic databases—including Pubmed, Embase, Web of Science, the Cochrane Library, PsycINFO, PsycARTICLES, and the Psychology and Behavioral Sciences Collection—were searched on February 14, 2019. There was no date, study design or language limit imposed in our search. All of the included studies satisfied our predetermined study population (pregnant mothers and their offspring), exposure (prenatal Cd exposure), and outcome measurements (adverse effects on cognitive development). The quality assessment for the included studies was conducted with the Newcastle-Ottawa Scale (NOS). Nine prospective cohort studies met the inclusion criteria, and six of them were assessed to be of high quality based on the NOS (NOS score ≥ 7). The prenatal Cd exposure was tested in maternal blood samples (4/9), umbilical cord blood samples (4/9), or maternal urinary samples (3/9). Among the nine studies included, six reported at least one inverse association between prenatal Cd exposure and the cognitive development of offspring, mainly in terms of language development (4/8), performance ability development (3/5), and general cognitive development (3/8). Furthermore, among six studies with high methodological quality (NOS score ≥ 7), prenatal Cd exposure was reported to be associated with language development in three studies (3/5), performance ability development in three studies (3/4), and general cognitive development in three studies (3/5). This systematic review provides convincing evidence that prenatal exposure to Cd is inversely associated with neurodevelopment of offspring. Larger prospective studies using standardized criteria and assessments of cognitive development are needed to confirm the dose-response effect and gender difference of prenatal Cd exposure on cognitive development of offspring.

Rare earth element (REE) concentrations and patterns were measured in surface water, suspended particles (SP) and oysters from the Pearl River Estuary, China. During the rainy season of 2017, higher REE concentrations were found at the stations in the estuary (ΣREE = 0.06–0.42 μg L⁻¹) than those at the river mouths (referred to as ‘outlet’ stations, ΣREE = 0.001–0.14 μg L⁻¹). However, the reverse occurred in the dry season of 2016 (ΣREE = 0.07–0.16 μg L⁻¹ in the mid-estuary vs. 0.001–0.02 μg L⁻¹in the outlet stations). Elevated concentrations of Pr, Nd, Dy and Ho, relative to the other REEs were found in water in both seasons at most sampling locations. However, in some estuary stations, no anomalies were detected in the SP or in the oysters while some anomalies were seen in SP from the outlet stations. Significant correlations between REE concentrations in SP and oysters as well as between both total REE concentrations and the La/Yb ratio (reflecting enhanced accumulation of light REEs (LREEs)) in oysters indicate that, in the Pearl River Estuary, the dominant REE uptake pathway in oysters is from particles.The elevated concentrations of Pr, Nd, Dy and Ho, which are reported here for the first time suggest that elevated levels of these elements may result from REE recycling and other industrialized activities in this area of southern China. Specific REEs could be used to indicate emerging contamination by the modern REE industry; furthermore, REE anomalies and patterns may be suitable tools to track REE sources.

Spiramycin is a widely used macrolide antibiotic and exists at high concentration in production wastewater. A thermal-acid hydrolytic pretreatment using silicotungstic acid (STA) under microwave (MW) irradiation was suggested to mitigate spiramycin from production wastewater. Positive correlations were observed between STA dosage, MW power, interaction time and the hydrolytic removal efficiencies, and an integrative equation was generalized quantitively. Rapid and complete removal 100 mg/L of spiramycin was achieved after 8 min of reaction with 1.0 g/L of STA under 200 W of MW irradiation, comparing to 30.1% by MW irradiation or 15.9% by STA alone. The synergetic effects of STA and MW irradiation were originated from the dissociated-proton catalysis by STA and the dipolar rotation heating effect of MW. STA performed much better than the mineral acid H2SO4 under MW, due to the much stronger Brönsted acidity and higher Hammett acidity. After 8 min, 98.0% of antibacterial potency was also reduced. The m/z 558.8614 fragment (P1) and m/z 448.1323 fragment (P2) were identified as the primary products, which were formed by breaking glucosidic bonds and losing mycarose and forosamine for P1 and further mycaminose moiety for P2. Finally, production wastewater with 433 mg/L of spiramycin was effectively treated using this thermal-acid hydrolytic method. Spiramycin and its antibacterial potency both dropped to 0 after 6 min. The potency drop was supposed from the losing of mycarose and/or forosamine. To decrease both the concentration of spiramycin and its antibacterial potency, combinedly using STA and MW was suggested in this work to break down the structural bonds of the functional groups rather than to destroy the whole antibiotic molecules. It is promising for pretreating spiramycin-contained production wastewater to mitigate both the antibiotic and its antibacterial potency.