Iron and steel industry emission is an important industrial source of air pollution. However, little is known about the relationship between volatile organic compounds (VOCs) emitted and regional air pollution. In this study, VOCs emissions from a typical iron and steel plant in Yangtze River Delta (YRD, China) were monitored from April 2018 to March 2019. The ozone formation potential (OFP) and secondary organic aerosol (SOA) formation of VOCs were calculated to reveal the influence of VOCs emissions on regional ozone and particulate pollution, and the sensitivity analysis approach was performed to explore the qualitative and quantitative relationships between VOCs and O₃, as well as VOCs and PM₂.₅. The VOCs concentration was 93.76 ± 266.97 ppbv during the study. The OFP was 760.08 ± 2391.90 μg m⁻³, and aromatics were the predominant precursors, contributing 54.05% of the total OFP. Furthermore, the SOA estimated by fractional aerosol coefficient (FAC) and time-resolved (TR) methods were 6.032 ± 13.347 μg m⁻³ and 0.971 ± 4.650 μg m⁻³, accounting for 8.65–26.39% (13.78 ± 7.46%) and 1.55–4.20% (2.22 ± 1.23%) of the PM₂.₅ concentrations, respectively. The results indicated that VOCs were more sensitive to O₃ pollution in high pollution domains, whereas VOCs were more sensitive to PM₂.₅ pollution in low pollution domains. We concluded that reducing VOCs emissions might be effective in alleviating photochemical pollution episodes in areas around iron and steel industry, and the haze pollution occurred in these regions may be caused by the primary emission of PM, and the contribution of SOA was relatively small.

In the present study, isolated strains of the microalgae Chlamydomonas sp. (CH) and Chlorella vulgaris (CV) were used to treat aquaculture wastewater and to obtain fatty acids and from a fattening culture of tilapia. The microalgae were cultivated for 11 days in tubular photobioreactors with an operating volume of 2 L, constant aeration and illumination. High removal rates of NO₃⁻ and PO₄³⁻ were achieved for both Chlamydomonas sp. (84.7% and 96%, respectively) and Chlorella vulgaris (94.6 and 97.9%, respectively). The maximum biomass productivity achieved by Chlamydomonas sp. was 0.06 and 0.10 gL⁻¹d⁻¹ for Chlorella vulgaris. Therefore, tilapia wastewater contained the necessary nutrient concentration for algal growth and development. Chlamydomonas sp. biomass lipid content was 69%, while that of Chlorella vulgaris was 40%. The lipid profile of both microalgae was abundant in palmitic acid (78% for Chlamydomonas sp. and 35% for Chlorella vulgaris). This fatty acid is suitable for biodiesel production. Tilapia wastewater is low-cost alternative culture medium as it contains the necessary nutrient concentration for microalgae development and growth.

In this study, the physicochemical properties, microstructure, and heavy metal leaching potential of various municipal solid waste incinerated-bottom ash (MSWI-BA) particle sizes were detected. The environmental risks that possibly result from the utilization of MSWI-BA aggregate in road construction are discussed. The air-dried MSWI-BA was sieved into four groups, including 4.75–9.5 mm, 2.36–4.75 mm, 0.075–2.36 mm, and < 0.075 mm. X-ray fluorescence (XRF), X-ray diffraction (XRD), and scanning electron microscopy (SEM) analyses were conducted. It was found that the main elements of MSWI-BA are Ca, Si, and Al; the major heavy metals are Zn, Cu, Cr, and Pb, and the main mineral compositions are quartz and calcite. Even though the major elements were found to be related to MSWI-BA particle size, the micropores, attached particles, and hydration products were shown to be independent on the particle size. The standard leaching test and a simulated leaching experiment with four solid/liquid ratios were implemented to study the leaching behavior of Zn, Cu, Pb, and Cr. Results showed that the leaching characteristics of selected metals were affected by the species of metal, MSWI-BA particle size, solid/liquid ratio, and the test method. The MSWI-BA aggregate was found to be an appropriate substitute material for natural aggregate in road construction due to its low metal leaching potential.

The coastal sediments in the northern Bay of Bengal has undergone contamination due to the heavy metal contribution from rivers. To evaluate the status of contamination in the inner shelf region of the Bay of Bengal, a sediment core chronologically constrained using ²¹⁰Pb dating technique from the northwest Bay of Bengal was investigated for several trace elements. To assess sediment quality, enrichment factor (EF), geo-accumulation index (Igeo), and Modified Nemerow Pollution Index (MPI) were derived. The influence on ecology by individual contaminants and combined contaminants was evaluated using the potential ecological risk factor (Erⁱ) and modified ecological risk index (MRI). The single-element pollution indices indicated that the sediment has no significant pollution by individual elements. However, the multi-elemental approach shows slight pollution in the sediment core. The ecology is at low risk by contaminants present in the sediment. Comparison of the elemental values of shelf sediment with adjacent riverine and estuarine samples demonstrates the role of estuarine environment and/or high riverine flux of sediments causing either removal or dilution of trace elements during its transport from the river to the sea.

Vermicomposting is a process by which earthworms together with microorganisms degrade organic wastes into a humus-like material called vermicompost. This process does not include a thermophilic stage, and therefore, the possible presence of pathogens represents a potential health hazard. To elucidate the effect of earthworms in the selective reduction of pathogens, grape marc substrate was artificially inoculated with Escherichia coli, Enterococcus spp., thermotolerant coliform bacteria (TCB), and Salmonella spp., and their reduction during vermicomposting was monitored. Various defense mechanisms eliminating microorganisms in the earthworm gut were assumed to be involved in the process of pathogen reduction. Therefore, we followed the expression of three pattern recognition receptors (coelomic cytolytic factor (CCF), lipopolysaccharide-binding protein (LBP), and Toll-like receptor (v-TLR)), two antimicrobial molecules (fetidin/lysenins and lysozyme), and heat shock protein HSP70. We detected the significant decrease of some defense molecules (fetidin/lysenins and LBP) in all pathogen-inoculated substrates, and the increase of CCF and LBP in the Salmonella spp.-inoculated substrate. At the same time, the reduction of pathogens during vermicomposting was assessed. We observed the accelerated reduction of E. coli, Enterococcus spp., and TCB in pathogen-inoculated substrates with earthworms compared to that without earthworms. Moreover, the differences between the microbiome of grape marc substrate and earthworm intestines were determined by high throughput sequencing. This analysis revealed that the bacterial composition of grape marc substrate differed from the composition of the content of earthworm intestines, suggesting the elimination of specific bacterial species during food passage through the gut.

This study used principal component analysis (PCA) to develop composite indexes for economic growth, environmental degradation, and social well-being. The mutual relationship between these indexes was empirically tested using a panel vector autoregressive model based on a generalized method of moment approach (PVAR-GMM), and robustness was determined with Driscoll and Kraay regression. To this end, we gathered the data for 36 Belt and Road Initiative (BRI) countries over the period 1995–2016. Using a multivariate framework, the empirical results showed that environmental degradation and social well-being have a significant positive impact on the economic growth index. The social well-being index and economic growth are contributors to environmental degradation. Similarly, economic growth, in the long run, improves social well-being. The results confirm bidirectional causality between economic growth and environmental degradation. Another bidirectional causal relationship was found between economic growth and social well-being. Further, causality exists from social well-being to environmental degradation, but not vice versa. The analysis of the impulse response function exhibited the presence of the environmental Kuznets curve phenomenon in BRI countries. Moreover, the results of variance decomposition suggested that a shock in one index spills over to other indexes simultaneously. The study suggests that policymakers should consider social well-being and environmental degradation in economic activity to achieve sustainable development goals.

Exposure to secondhand smoke (SHS) in the workplace has led many workplaces to set up smoke-free policies to protect non-smoking employees. Although smoke-free workplaces are pervasive, the intensity of the practice is questionable. The purpose of this review is to identify the pooled prevalence estimate of secondhand smoke at smoke-free workplaces and the factors associated with SHS exposure at the workplace despite existing smoke-free policies. Fourteen studies (total 7458 employees) were identified from Pubmed, ScienceDirect, Cinahl, Scopus, and Web of Science from inception to December 2017. Results indicate that despite the existence of smoke-free policies at the workplace, 14 studies reported exposure to secondhand smoke. The pooled prevalence of the SHS exposure was 0.29 (95% CI = 0.23 to 0.36) (P < 0.001). Male young adults working in the hospitality industry are likely to report exposure to secondhand smoke at the smoke-free workplace. While most of the selected studies show the exposure of SHS within the smoking ban workplace, only two studies reported no exposure to secondhand smoke after implementation of smoke-free policies. Although the smoking ban policy at the workplace has been introduced, there are still a number of employees being affected by secondhand smoke. This indicates that there is still a gap of knowledge, attitude, and practice of non-smokers in strengthening the smoke-free policy at the workplace.

In this study, effects of ultrasound pretreatment on combustion characteristics and elemental composition of municipal sludge were examined for energy-based evaluation of sludge pretreatment. Waste activated sludge (WAS) from a municipal wastewater treatment plant was pretreated with ultrasound at varying durations and was subjected to anaerobic digestion in a biochemical methane potential (BMP) assay. Changes in gas production rates, calorific value (CV), elemental compositions, and ash contents of sludge samples were examined to assess the effects of pretreatment and digestion. Sonication at 0.73 W/mL enhanced gas production by 28%. Moreover, volatile solids (VS) and chemical oxygen demand (COD) removals increased from 41 to 45% and 33 to 37%, respectively. Following anaerobic digestion, CVs of samples decreased by about 18%. Sonicated samples exhibited a higher decrease. In order to quantify the change in overall energy content, total solids (TS) reduction was also taken into account. Loss was magnified as both CV and the amount of TS that would provide the overall energy were reduced. This loss was 38% for the control group and 41% for the 15 min sonicated sludge. Digestion decreased the C content of sludge by about 20% and H content by 50% due to biogas production. Ash content increased relatively as some of the combustible solids were lost due to digestion. Experimental results indicate that if sludge is to be combusted, digestion with or without ultrasound pretreatment may be disadvantageous if the aim is to maximize energy gain from sludge.

The aim of this work is to study the byproducts formed as a result of the photocatalytic process under different conditions of light wavelength and photocatalyst doping, rendering valuable information about the fate of pollutants for water treatment applications. Salicylic acid was selected as a model emerging pollutant and powders of nitrogen-doped titanium dioxide (N-TiO₂) and TiO₂ were prepared by the sol-gel process, using TiO₂ P-25 Degussa as benchmark. Two light sources, UVA fluorescent tubes (372 nm) and blue LEDs (462 nm), were employed for photolysis and photocatalysis experiments. Transformation products formed during the process were studied by high-performance liquid chromatography coupled to mass spectrometry (HPLC-MS). Major differences were found in the amount and identity of the transformation products due to the different light sources, detecting similar transformation products among the studied catalysts. Under UVA light, hydroxylated and carbonylated byproducts were the first intermediates to reach maximum abundances whereas presumed ring opening products were the last ones. On the other hand, under blue LED illumination byproducts accumulated with decreased mineralization. Photocatalytic degradation pathways were proposed based on the findings.

Mesoporous ZSM-5 zeolite (MZ) was used as support for Cu and Ce species, and the effects of structure and physical-chemical properties on selective catalytic reduction of NO with NH₃ (NH₃-SCR) were investigated. The characterization and experimental results show that the high activity of the Cu-Ce/MZ catalyst could be due to its high surface area, more and uniformly distributed active sites, and abundant oxidative species. Compared with the conventional ZSM-5 and SBA-15, the Cu-Ce/MZ possesses large amount of mesopores, and more accessible active sites, which are beneficial to accelerate the diffusion and improve the internal mass transfer in the denitration process. The Cu-Ce/MZ catalyst shows higher activity than Cu-Ce/ZSM-5 and Cu-Ce/SBA-15 at 200 °C.