Air pollution is an important cause of non-communicable diseases globally with particulate matter (PM) as one of the main air pollutants. PM is composed of microscopic particles that contain a mixture of chemicals and biological elements that can be harmful to human health. The aerodynamic diameter of PM facilitates their deposition when inhaled. For instance, coarse PM having a diameter of < 10 μm is deposited mainly in the large conducting airways, but PM of < 2.5 μm can cross the alveolar-capillary barrier, traveling to other organs within the body. Epidemiological studies have shown the association between PM exposure and risk of disease, namely those of the respiratory system such as lung cancer, asthma, and chronic obstructive pulmonary disease (COPD). However, cardiovascular and neurological diseases have also been reported, including hypertension, atherosclerosis, acute myocardial infarction, stroke, loss of cognitive function, anxiety, and Parkinson’s and Alzheimer’s diseases. Inflammation is a common hallmark in the pathogenesis of many of these diseases associated with exposure to a variety of air pollutants, including PM. This review focuses on the main effects of PM on human health, with an emphasis on the role of inflammation.

Radon exhaled from building material surfaces is an important source of indoor radon. Yangjiang, located in the southern part of mainland China, is well-known as a high background radiation area (HBRA). Rather, high levels of radon and thoron concentration have been observed in adobe and brick houses. Reducing the indoor radon concentration remains an important issue in the high background radiation areas of China and the world. Generally, the walls of Chinese dwellings are solid. In this paper, a simple one-dimensional model for predicting the radon diffusion in a cavity wall is proposed, and an analysis formula describing the radon exhalation rate from cavity wall surfaces is presented. The influence on the radon exhalation rate due to leakage through structural joints and building material cracks is analyzed. The simulation results indicate that the radon exhalation rate from a cavity wall surface is far lower than that from a solid wall. The structure of cavity walls themselves is therefore useful as a mechanism for reducing the indoor radon in high background radiation areas across the world.

This study aims to examine the impact of public-private partnerships (PPP) investment in energy, technological innovations (TI), economic growth (EG), exports, and foreign direct investment (FDI) on CO₂ emissions in Brazil over the period from 1984 to 2018. In doing so, we employ the Ng-Perron unit root test to examine the stationarity and autoregressive lag distributed (ARDL) model for cointegration between CO₂ emissions and its determinants. The outcomes are as follows: first, in the long run, the PPP investment in energy deteriorates the environmental quality by increasing CO₂ emissions, while TI has a significant negative effect on CO₂ emissions. It is also found that the exports and FDI degrade the environmental quality and the relationship between EG and CO₂ emissions is inverted U-Shaped, presence of the EKC hypothesis. Second, in the short run, PPP investment in the energy sector is negatively influencing, while TI has a positive association with carbon emissions. The empirical findings provide new insights for policymakers to regulate PPP investment in the energy sector for the improvement of environmental quality in Brazil. Graphical abstract

Chrome-tanned leather solid wastes (leather finished trimmings (LFT) and chrome shavings (CS)) from tanneries were studied using pyrolysis and incineration. Detailed characterization of CS and LFT indicated higher calorific value of 15.77 MJ/kg and 19.97 MJ/kg respectively, which makes it suitable for thermal treatment. Thermal Gravimetric Analysis (TGA) of CS and LFT recorded a weight loss of 79.82% and 68.22% at 800 °C respectively. Energy-dispersive X-ray spectroscopy and scanning electron microscopy analysis for CS and LFT were also carried out. Pyrolysis of CS and LFT was carried out using a fixed bed–type pyrolysis unit at a temperature of 500 ± 10 °C for a reaction time of 30 min and three different by-products (bio-oil, biochar and pyrolytic gas) were obtained as a result of pyrolysis. From pyrolysis process, higher bio-oil yields of 52 wt.% and 49 wt.% from LFT and CS with calorific value of 28.0 and 27.8 MJ/kg respectively were obtained. The calorific values of the biochar obtained from LFT and CS were found to be 20.5 and 23.0 MJ/kg respectively. Incineration was carried out in the existing incineration facility of 150 kg/h capacity at a temperature of 1200 °C. The results of incineration process showed a higher weight reduction (93.0 wt.%) and higher concentration of gaseous emissions, revealing the need for off-gas treatment. Further, FT-IR spectra of residual ash from the incineration process revealed the occurrence of oxidation of trivalent chromium to its hexavalent form, which could be a potential raw material in the metallurgical/chemical industry for the synthesis of sodium chromate or ferrochrome alloy. Comparative experimental investigations of pyrolysis and incineration revealed that incineration could be a potential treatment and disposal option, in developing countries like India, for chrome-tanned leather solid wastes from tanneries, for producing heat energy and the residue with potential utilization viability in another industry paving a way towards circular economy.

A uniformly distribution of 3 wt.% Mo (with tetrahedral coordination) on a commercial HY zeolite having both micro- and meso-pores, provided a new active catalyst which resulted 100% removal of DBT in this work. Respectively, H₂O₂ and acetonitrile were used as the oxidant and extraction solvent for oxidative desulfurization (ODS) at a mild condition. The structure of three-dimensional meso-pores, despite major micro-pores, was proved to be intriguing for the use of acidic HY zeolite as a support material in this process. The catalyst samples were characterized by different analyses of XRPD, XRF, FTIR, SEM, EDX, TEM, N₂ adsorption desorption, BET, BJH, UV-vis, and NH₃-TPD. High amounts of Mo were not in favor of the catalytic performance because of increasing non-framework polymolybdate formation, which led to decreasing meso-pore volume. Acid sites strength also decreased by increasing Mo content. The Mo active sites at a low loading of 3 wt.% reached the best performance for the complete removal of DBT (t = 90 min, T = 60 °C, catalyst/fuel = 8 g/L, O/S = 2, VSₒₗᵥₑₙₜ/VOᵢₗ = 1/2, DBT = 1000 ppm), mainly due to the presence of isolated Mo species in the framework of HY. The efficiency still reached to 90% after recycling the catalyst three times. The reusability of catalyst revealed the adsorption of the aqueous phase by this hydrophilic catalyst during the process being as a major deactivation factor. This was significantly diminished via a subsequent washing by acetonitrile.

Flax (Linum usitatissimum L.), one of the oldest cultivated crops, continues to be widely grown for oil, fiber and food. Furthermore, the plants show a metal tolerance dependent on species so is ideal for research. Present study was conducted to find out the influence of copper (Cu) toxicity on plant biomass, growth, chlorophyll content, malondialdehyde (MDA) contents, proline production, antioxidative enzymes and metal up taken by L. usitatissimum from the soil grown under mixing of Cu-contaminated soil with natural soil by 0:1 (control), 1:0, 1:1, 1:2 and 1:4. Results revealed that, high concentration of Cu in the soil affected plant growth and development by reducing plant height, plant diameter and plant fresh and dry biomass and chlorophyll contents in the leaves compared with the control. Furthermore, Cu in excess causes generation of reactive oxygen species (ROS) such as superoxide radical (O–) and hydroxyl radicals (OH), which is manifested by high malondialdehyde (MDA) and proline contents also. The increasing activities of superoxidase dismutase (SOD) and peroxidase (POD) in the roots and leaves of L. usitatissimum are involved in the scavenging of ROS. Results also showed that L. usitatissimum also has capability to revoke large amount of Cu from the contaminated soil. As Cu concentration in the soil increases, the final uptake of Cu concentration by L. usitatissimum increases. Furthermore, the soil chemical parameters (pH, electrical conductivity and cation exchange capacity) were increasing to highest levels as the ratio of Cu concentration to the natural soil increases. Thus, Cu-contaminated soil is amended with the addition of natural soil significantly reduced plant growth and biomass, while L. usitatissimum is able to revoke large amount of Cu from the soil and could be grown as flaxseed and a potential candidate for phytoremediation of Cu.

Endocrine-disrupting compounds are attracting attention worldwide because of their effects on living things in the environment. Ten endocrine disrupting compounds: 4-nonylphenol, 2,4-dichlorophenol, estrone, 17β-estradiol, bisphenol A, 4-tert-octylphenol, triclosan, atrazine, imidazole and 1,2,4-triazole were investigated in four rivers and wastewater treatment plants in this study. Rivers were sampled at upstream, midstream and downstream reaches, while the influent and effluent samples of wastewater were collected from treatment plants near the receiving rivers. Sample waters were freeze-dried followed by extraction of the organic content and purification by solid-phase extraction. Concentrations of the compounds in the samples were determined with ultra-high performance liquid chromatography-tandem mass spectrometry. The instrument was operated in the positive electrospray ionization (ESI) mode. The results showed that these compounds are present in the samples with nonylphenol > dichlorophenol > bisphenol A > triclosan > octylphenol > imidazole > atrazine > triazole > estrone > estradiol. Nonylphenol has its highest concentration of 6.72 μg/L in King Williams Town wastewater influent and 2.55 μg/L in midstream Bloukrans River. Dichlorophenol has its highest concentration in Alice wastewater influent with 2.20 μg/L, while it was 0.737 μg/L in midstream Bloukrans River. Uitenhage wastewater effluent has bisphenol A concentration of 1.684 μg/L while it was 0.477 μg/L in the downstream samples of the Bloukrans River. Generally, the upstream samples of the rivers had lesser concentrations of the compounds. The wastewater treatment plants were not able to achieve total removal of the compounds in the wastewater while runoffs and wastes dump from the cities contributed to the concentrations of the compounds in the rivers.

Pesticide chlorothalonil is widely applied in tea agroecosystem, potentially disturbing soil microbial-mediated nitrogen cycle. The underlying toxicity mechanism, however, is not well explored. Here, we investigated the long-term effects of chlorothalonil on soil microbial denitrification and N₂O emission pattern in a tea field after 40 days of exposure. Results showed that chlorothalonil inhibited denitrification process but remarkably promoted N₂O emission by 380–830%. Chlorothalonil significantly inhibited N₂O reductase activity but did not affected nosZ abundance. Our results further revealed that chlorothalonil influenced soil denitrification by directly suppressing microbial electron transport system activity, and decreasing electron donor nicotinamide adenine dinucleotide (NADH) and energy source adenosine triphosphate (ATP) levels. Additionally, chlorothalonil also downregulated denitrifying functional genes (narG, nirS, and norB) and declined the relative abundances of potential denitrifiers (i.e., Pseudomonas and Streptomyces). Stepwise regression and path modeling suggested that nitrate reductase was the most significant factor in explaining denitrification rate under chlorothalonil applications. This study provides important information for revealing the chronic impacts of pesticide on tea soil denitrification and N₂O emission on the basis of electron transport mechanism. Most significantly, N₂O emission is underestimated in chlorothalonil-treated soils, which suggests that future estimations of N₂O emission from agricultural lands should take account of pesticide dependency conditions.

This case-control study aimed to investigate the relationship of indoor radon gas concentration and residential building characteristics with mental health with multiple sclerosis (MS) in Yazd City, Iran. The participants included 45 patients with MS and 100 healthy individuals. The participants’ socio-economic status and residential building characteristics were investigated using a questionnaire. The radon gas concentration was also measured by CR-39 detectors over a 6-month period. Furthermore, the participants’ mental health data were collected using General Health Questionnaire (GHQ-28). The mean concentrations of radon gas were 66.77 and 65.33 Bq/m³ in the homes of patients with MS and healthy individuals, respectively, but the difference was not significant (p = 0.882). However, the radon gas concentration had a significant relationship with the building’s age (p = 0.038), ventilation (p = 0.053), and cooling system (p = 0.021). A significant difference was observed between the two study groups in terms of the mental health (p = 0.018), depression (p = 0.037), somatic symptoms (p ≤ 0.001), and physical activity (p = 0.030). Since the indoor radon gas concentration did not have any significant relationship with MS prevalence, more studies are required in this regard, especially in long-term exposure.

An air sampling study was conducted to evaluate personal formaldehyde exposures in a group of office workers spread across five geographical locations in the USA. Passive badge samples for formaldehyde were collected on three participants in each location, as well as in the office and home indoor microenvironments of each participant over 3 individual days. Median personal 24-h formaldehyde concentrations ranged from 9.9 to 18 μg/m³. Personal 24-h formaldehyde concentrations in one location were significantly higher than concentrations measured in the other four locations; no significant differences existed between any of the other locations. The participants in this study spent an average of 53% of their daily time in their homes, 36% at their office, and 11% in other indoor and outdoor locations. A comparison of measured 24-h personal formaldehyde concentrations and a model of average exposure based upon measured concentrations in the indoor microenvironments suggested that both the home and office formaldehyde concentrations were a strong predictor (R² = 0.88) of overall personal exposure. The data from this study are representative of office workers in urban environments and can be used as background formaldehyde exposure levels (in the absence of specific sources) for both occupational and nonoccupational exposure assessments.