Essential oils are frequently used as natural fragrances in housecleaning products and air fresheners marketed as green and healthy. However, these substances are volatile and reactive chemical species. This review focuses on the impact of essential oil-based household products on indoor air quality. First, housecleaning products containing essential oils are explored in terms of composition and existing regulations. Specific insight is provided regarding terpenes in fragranced housecleaning products, air fresheners, and pure essential oils. Second, experimental methodologies for terpene monitoring, from sampling to experimental chambers and analytical methods, are addressed, emphasizing the experimental issues in monitoring terpenes in indoor air. Third, the temporal dynamics of terpene emissions reported in the literature are discussed. Despite experimental discrepancies, essential oil-based products are significant sources of terpenes in indoor air, inducing a high exposure of occupants to terpenes. Finally, the fate of terpenes is explored from sorptive and reactive points of view. In addition to terpene deposition on surfaces, indoor oxidants may induce homogeneous and heterogeneous reactions, resulting in secondary pollutants, such as formaldehyde and secondary organic aerosols. Overall, essential oil-based products can negatively impact indoor air quality; therefore, standard protocols and real-scale approaches are needed to explore the indoor physics and chemistry of terpenes, from emissions to reactivity.

Urban air pollution is a serious environmental problem in developing countries worldwide, and health is a pressing issue in the megacities in Latin America. Buenos Aires is a megacity with an estimated moderate Air Quality Index ranging from 42 to 74 μg/m³. Exposure to Urban Air Particles from Buenos Aires (UAP-BA) induces morphological and physiological respiratory alterations; nevertheless, no studies on extrapulmonary organs have been performed. The aim of the present study was to explore the health effects of chronic exposure to UAP-BA (1, 6, 9, and 12 months) on the liver, heart, and serum risk biomarkers. BALB/c mice were exposed to UAP-BA or filtered air (FA) in inhalation chambers, and liver and heart histopathology, oxidative metabolism (superoxide dismutase, SOD; catalase, CAT; lipoperoxidation, TBARS), amino transaminases (AST, ALT) as serum risk biomarkers, alkaline phosphatase (ALP), paraxonase-1 (PON-1), and lipoprotein-associated phospholipase A2 (Lp-PLA2) were evaluated. Chronic exposure to real levels of UAP in Buenos Aires led to alterations in extrapulmonary organs associated with inflammation and oxidative imbalance and to changes in liver and heart risk biomarkers. Our results may reflect the impact of the persistent air pollution in Buenos Aires on individuals living in this Latin American megacity.

In order to realize the effective measurement of environmental pollution loss (EPL) caused by waste gas emits from energy consumption in industrial parks, it is built a shadow price model of waste gas emits in this study on the basis of literature review and status analysis. The measurement model is applied to Nanjing MV Industrial Park by using relevant statistical data. It is found that the total environmental pollution loss of waste gas emits from energy consumption in Nanjing MV Industrial Park presents a “U” change trend, which first decreases and then increases. In terms of the composition of environmental pollution loss of waste gas emits, environmental pollution loss caused by SO₂ and NO₂ stays high, which are the main components of environmental pollution loss and would be the focus of energy conservation and emission reduction in Nanjing MV Industrial Park in the future. The research results provide an effective quantitative analysis method for local government to measure the environmental pollution loss of waste gas emits from energy consumption in industrial parks and to formulate policies for environmental pollution treatment. Graphical abstract

Individuals with higher contaminant burdens are expected to be in poorer physical health and be of lower individual body condition and energetic status, potentially resulting in reduced ornamentation or increased asymmetry in bilateral features. The degree and magnitude of this effect also would be expected to vary by sex, as female birds depurate contaminants into eggs. We tested for relationships among mercury in feathers, sex, and elaborate feather ornaments that relate to individual quality in crested auklets (Aethia cristatella), small planktivorous seabirds in the North Pacific Ocean. We found no relationships between mercury and the size of individuals’ forehead crest or degree of measurement asymmetry in auricular plumes, both of which are favoured by intersexual selection. Females had significantly greater mercury concentrations than males (females. 1.02 ± 0.39 μg/g; males, 0.75 ± 0.32 μg/g); but concentrations were below that known to have physiological effects, as expected for a secondary consumer. Sex differences in overwintering area for this long-distance migrant species (more females in the Kuroshio Current Large Marine Ecosystem than males) could be the reason for this seemingly counterintuitive result between sexes. Further research relating mercury burden to overwintering ecology and diet contents would build on our results and further elucidate interrelationships between sex, sexually selected feather ornaments and contaminant burden.

Plastics are widely considered to be a major threat particularly in the urban areas owing to extensive use of plastic products. The current study is the first investigation to highlight the microplastics (MPs) pollution from the freshwater (Ravi River) located in the predominant urban center, i.e., Lahore, Pakistan. The concentration profile was quantified from surface water (n = 19) and sediments (n = 19) collected from different drains and canals of predominant freshwater resources in Lahore, Pakistan. The highest content of MPs was observed in the sullage carrier with mean concentration of 16,150 ± 80 MPs/m³ and 40,536 ± 202 MPs/m² in the water and sediments respectively. The lowest level was detected in the link canals with mean concentration of 190 ± 141 MPs/m³ in the water and 683 ± 479 MPs/m² in the sediments. The proportion of large size MPs (300 μm–5 mm) was maximum in the upstream section of Ravi river, whereas fine size MPs (50–150 μm) were dominant in the downstream section. In terms of shapes, the fragments were predominant with a relative abundance of 56.1% and 83.1% followed by fibers with a relative abundance of 38.6% and 11.8% in the water and sediments respectively. The chemical composition analysis showed that most of the fibers, fragments, and beads were polyethylene while the sheets were composed of polypropylene. Nevertheless, the foams isolated from the samples were composed of polystyrene. Within 24 h, about 2.4 ± 2.4 billion microplastic pieces were estimated to be transported from a single water channel into the river. The highest discharge of MPs was estimated from the sullage carrier with about 7 billion pieces/day.

The fast-growing discharge of effluents of engineered nanomaterials (ENM) and heavy metals in freshwater ecosystems raises concern in recent times. This study investigated the effects of the co-exposure between nanoparticles (TiO₂ NPs) and lead (Pb) in a simplified freshwater food web model, including zooplankton (copepods sp.) and Clarias gariepinus on bioaccumulation and antioxidant activity. We carried out a chronic (28 days) semi-static bioassay by feeding individually fish with zooplankton exposed to TiO₂ NPs (0.09 and 0.20 μM), Pb (0.01 and 0.04 μM), and their binary mixtures. The binary mixtures caused a significant (p < 0.05) decrease in malondialdehyde (1.64–2.01-fold), catalase (3.18–3.89-fold), glutathione reductase (1.37–1.46-fold), and glutathione peroxidase (1.19–1.89-fold) levels. Lead accumulated in the tissues had bioaccumulation factor between 0.40 and 1.42 in binary mixture. These results indicate that chronic exposure of TiO₂ NPs could influence the BAF of Pb, neurotoxicity, changes of antioxidant enzymes, and retardation of food uptake. These findings raise concerns regarding the fate of higher trophic levels in polluted freshwater ecosystems with a binary mixture of engineer nanomaterials and heavy metals.

The main objective of this paper is to estimate the interfuel substitution elasticities between hydropower and the fossil fuels of coal and natural gas used in the generation of electricity for Malaysia. Due to the violation of the assumption behind the ordinary least squares (OLS) method on account of the correlated error terms in the system of equations, the econometrics techniques of seemingly unrelated regression (SUR) was adopted to obtain the parameter estimates using dataset that covers the period 1988 to 2016. The main finding is that there exists substantial substitution possibility between hydropower and fossil fuels in the generation of electricity for Malaysia. CO₂ emissions mitigation scenarios were also conducted to explore the possible effects of substituting fossil fuels for hydropower to generate electricity. The results show that switching from high carbon-emitting fuels to renewable energy such as hydropower will substantially reduce CO₂ emission and assist the country towards achieving the carbon emissions reduction targets. Policy recommendations are offered in the body of the manuscript.

Atmospheric PM₂.₅-bound polycyclic aromatic hydrocarbons (PAHs) were analyzed over urban and rural sites during January to December 2018. Total annual average concentration of PM₂.₅ was 74.41 ± 24.96 μg/m³ over urban and 52.03 ± 13.11 μg/m³ over rural site during study time. The annual average concentration of PM₂.₅ over urban and rural atmospheres were found approximately twice in urban and found also higher over rural site, with respect to National Ambient Air Quality (NAAQ) standard of 40 μg/m³ for PM₂.₅ concentration. The annual concentration of PAHs was 750.80 ± 19.49 ng/m³ over urban, and, over rural, it was 559.59 ± 17.56 ng/m³. The seasonal variation of concentration of PAHs was in order of winter > post-monsoon > summer > monsoon. The most predominant PAHs were IcP (17.21%), B(ghi) P(15.22%), BkF (11.60%), DBahA (11.34%) and BbF (10.91%) to the total PAH concentration over urban site; over rural site, most predominant PAHs were IcP (16.02%), B(ghi)P, (15.63%), BkF (11.46%), DBahA (11.12%) and BbF (8.99%) of total PAHs. DBahA concentration was contributed approximately 46% carcinogenicity over both urban and rural sites, and BaP contributes 33.56% carcinogenicity over urban site and 34.62% carcinogenicity over rural site of total PAH samples. The Excess Life Time Cancer Risk (ELCR) values over urban were found at acceptable limit 10⁻⁶–10⁻⁴ given by the United States Environmental Protection Agency. Over rural site, the ELCR value was found near about acceptable limit. Diagnostic ratio analysis demonstrated that major sources of PAHs were pyrogenic sources and vehicular emission over study. Air parcel through trajectories over study site also contributed in PAH concentration.

Slim tobacco products shall appear by their look less harmful. In 2013, the European Union ministers discussed to ban them. However, only a ban on small package sizes was realized. To add more data for exposure risk assessment of slim tobacco products, the particulate matter (PM) amount in second-hand smoke (SHS) of super-slim size cigarettes compared with a king size brand was investigated. PM amount of four super-slim size cigarette types of the brand Couture was analysed in comparison with the king-size reference cigarette. Therefore, SHS was produced in an enclosed space with a volume of 2.88 m³ by an automatic environmental tobacco smoke emitter. PM size fractions PM₁₀, PM₂.₅ and PM₁ were measured in real time using a laser aerosol spectrometer. SHS of Couture Gold contained about 36% and Couture Purple about 28% more PM than the reference cigarette. In contrast, Couture Green emitted about 37% and Couture Silver about 53% less PM than the reference cigarette. Depending on the brand, the PM₂.₅ mean concentrations increased up to 1538 μg/m³. This exceeds the 24-h mean concentration of at most 25 μg/m³ according to the WHO Air quality guidelines about 62-fold. Smoking in enclosed rooms leads to a massive increase of PM. The PM pollution by slim-size tobacco products are substantial and sometimes higher than by king size tobacco products. Therefore, SHS exposure from slim-size tobacco products is not less harmful to health. Decision makers should take this aspect in consideration.

In situ chemical oxidations are known to remediate PAH contaminations in groundwater and soils. In this study, batch-scale oxidations aim to compare the PAC (polycyclic aromatic compound) degradation of three oxidation processes traditionally applied for soil treatment: permanganate, heat-activated persulfate (60 °C) and Fenton-like activated by magnetite, to results obtained with ferrates (Feⱽᴵ). Widely studied for water treatments, ferrates are efficient on a wide range of pollutants with the advantage of producing nontoxic ferric sludge after reaction. However, fewer works focus on their action on soil, especially on semi-industrial grade ferrates (compatible with field application). Oxidations were carried out on sand spiked with dense non-aqueous phase liquid (DNAPL) sampled in the groundwater of a former coking plant. Conventional 16 US-EPA PAHs and polar PACs were monitored, especially potential oxygenated by-products that can be more harmful than parent-PAHs. After seven reaction days, only the Fenton-like showed limited degradation. Highest efficiencies were obtained for heat-activated persulfate with no O-PAC ketones formed. Permanganate gave important degradation, but ketones were generated in large amount. The tested ferrates not only gave slightly lower yields due to their auto-decomposition but also induced O-PAC ketone production, suggesting a reactional pathway dominated by oxidoreductive electron transfer, rather than a radical one.