Concentrations Of Organic Compounds Research Articles

Low-cost sensor-based investigation of CO2 and volatile organic compounds in classrooms: Exploring dynamics, ventilation effects and perceived air quality relations

Poor classroom air quality (CAQ) can have negative impacts on student health, well-being and performance. Although CO2 concentrations are the proxy most often applied when assessing classroom ventilation and air quality, volatile organic compounds (VOCs) are important contributors to classroom air pollution. However, little is known about the sources and dynamics of VOCs in classrooms and its relation to classroom occupancy, ventilation and perceived air quality. In this study, CAQ was investigated in 75 Danish classrooms throughout November 2021 using low-cost sensors for continuous measurements of occupancy, CO2- and total volatile organic compound (TVOC) concentrations in conjunction with thermal desorption gas chromatography mass spectrometry (TD-GC-MS) analysis of organic compounds. Measurements show significant increases in TVOC concentrations during school hours as well as a day-to-day increase in the morning TVOC levels from insufficient ventilation from preceding days. A weak (r = 0.21) but significant (p < 0.01) correlation was found between classroom CO2 and TVOC. However, unlike the CO2 concentrations, TVOC concentrations were affected by episodic emissions from classroom activities. Ventilation type was identified as a key factor influencing both CO2- and TVOC levels. Although mechanically ventilated classrooms experienced significantly lower CO2- and TVOC levels compared to naturally ventilated classrooms, all classrooms exceeded guideline values of 1000 ppm CO2 with 70% of the classrooms exceeding this more than half of the occupied time. In contrast to CO2, a positive correlation was identified between the median TVOC concentrations during occupancy and the reported perceived CAQ.

Incidence of circular refurbishment measures on indoor air quality and comfort conditions in two real buildings: Experimental and numerical analysis

The application of Circular Economy to construction sector is a key to attain carbon neutrality, since it is responsible of 40 % of natural resource consumption. In this frame the importance of an efficient building refurbishment process throughout recycled material and renewable energy is fundamental. From an overview about building refurbishment emerges the need to investigate aspects related to Indoor Environmental Quality and the comparison between in-field measurements with output of dynamic simulation models. The present study aims to fill these two gaps by means an energy renovation of two real buildings in Greece. The work develops within the European project “Drive 0″, born to promote deep environmentally friendly retrofitting by means of circular renovation concepts. The methodological approach involves on-site monitoring of a series of parameters describing the energy, microclimate environmental and air quality, before and after the energy requalification. In addition, a numerical model developed in Building Energy Simulation program is calibrated and a Computational Fluid Dynamics is developed. From the in-field measurements emerges that, on one hand, the refurbishment of heating system shows a great improvement of indoor thermal conditions, with Total Volatile Organic Compounds concentration that sometimes exceed 3.0 mg/m3; on the other hand an integrated thermal insulation reduces infiltrations and changes the envelope behaviour, with a global energy saving of 30 % during winter and autumn periods.Another result of the study shows that a numerical model developed in Building Energy Simulation program and calibrated on energy consumption can greatly fit the local thermal comfort distribution of the occupant zone and predict the indoor air quality, if it outputs are used as input data in a Computational Fluid Dynamics study. These results can be beneficial to decision makers and designers for evaluating emitters positioning, opening design and mechanical ventilation strategies, aimed at reducing energy costs.

Combined Pre-Treatment Technologies for Cleaning Biogas before Its Upgrading to Biomethane: An Italian Full-Scale Anaerobic Digester Case Study

Biogas produced by anaerobic digestion contains different types of contaminants, and it is preferable to eliminate those contaminants before biogas’ energetic valorization or upgrading to biomethane as they are harmful to human health and detrimental to combustion engines. This study presents the biogas cleanup system optimized by an Italian full-scale anaerobic digester treating food waste (FW) and represented by micro-oxygenation, chemical scrubber, cooling, and activated carbon sections. The cleaned biogas is upgraded to biomethane using a membrane-based upgrading unit and injected into the natural gas network for transport sector use. H2S and volatile organic compound (VOC) concentration in raw biogas was reduced from an annual average value of 1207 ppmv and 895 mg/Nm3, respectively, to below 0.1 mg/Nm3 in the final biomethane. In the summer, the H2S average content in raw biogas was 833 ppmv due to a greater presence of low-sulfur-containing vegetables in FW, while in the winter it was an average of 1581 ppmv due to a larger portion of protein-containing FW. On the other hand, raw biogas VOC content in the winter was an average of 1149 mg/Nm3, with respect to 661 mg/Nm3 in the summer, due to the greater consumption of citrus fruits containing high amount of terpene compounds. The concentration of other trace contaminants, such as HCl, NH3, and siloxanes, was lowered from 17, 36, and 0.6 mg/Nm3 in raw biogas, respectively, to below 0.1 mg/Nm3 in the final biomethane. All the considerations and evaluations underlying the technological and plant engineering choices together with the individuation of the best operating conditions are discussed.

Effect of brassinosteroids on rooting of the ornamental deciduous shrubs

Brassinosteroids are a developing group of growth regulators. They are a group of steroid hormones involved in plants’ physiological and developmental processes. Among other things, they are responsible for cell wall regeneration or cell elongation. This experiment aimed to examine the effect of rooting stimulants on rhizogenesis in cuttings of two deciduous shrub species: Philadelphus ’Virginal’ and Hydrangea paniculata ’Limelight’. Aqueous solutions of indole-3-butyric acid (IBA) at 200 mg·L–1, Brassinolide (BL) at 0.05% and 24-epibrassinolide (24epiBL) (0.05%) were used in this study. The results obtained showed that both auxin and both of the brassinosteroids used increased the percentage of rooted cuttings almost twice, the degree of rooted cuttings and root length – for BL + IBA – longer roots than the control by 41% in jasmine and by 59% in hydrangea. The growth regulators applied during the rooting of cuttings also caused changes in the organic compound content of plant tissues and the activity of oxidative stress enzymes. The studies and results suggest that brassinosteroids may soon replace the popular rooting stimulants.

Characterization of persistent organic contaminants in the atmosphere of Gadani's ship breaking yards and its surrounding: Implications for sustainable ship recycling practices

Gadani is internationally renowned for its extensive ship-breaking operations, positioning it as one of the globe's primary ship-breaking hubs. A comprehensive study was conducted to evaluate the presence of organic contaminants in the air within Gadani, encompassing the areas surrounding ship-breaking facilities, proximate residential settlements, and adjacent roadways. Passive air samplers were employed to collect a total of 30 air samples. The analytical results unveiled a notably elevated concentration of specific organic compounds, with a pronounced prevalence of polycyclic aromatic hydrocarbons (PAHs), short-chain chlorinated paraffins (SCCPs), and polychlorinated biphenyls (PCBs) at the ship-breaking yard. Notably, dichlorodiphenyltrichloroethanes (DDTs) and DDE were detected at substantially lower levels. In particular, sites in close proximity to ship-breaking activities exhibited elevated concentrations of PCBs (Σ7PCB 0.065429 to 7.345714 ng/sample), PAHs (Σ8PAH 2.44 to 134.23 ng/sample), and SCCPs (0.18 to 25.6 ng/sample). Conversely, DDTs and DDE demonstrated higher concentrations near residential settlements. The evaluation of Molecular Diagnostic Ratios for PAHs revealed anthracene/anthracene + phenanthrene ratios of 0.88, 0.69, and 0.5 for ship-breaking areas, roadside locations, and community surroundings, respectively. Furthermore, the benz[a]anthracene/benz-[a]anthracene + chrysene molecular ratios were measured at 0.77 (ship-breaking sites), 0.82 (roadside), and 0.83 (community), respectively. The molecular ratio of fluoranthene/fluoranthene + pyrene at ship-breaking sites was 0.23, while roadside and community ratios were 0.36 and 0.89, respectively. These findings underscore the significant contribution of ship-recycling activities to the atmospheric release of SCCPs, PCBs, and PAHs, emphasizing the global imperative for responsible ship recycling practices.

Association between blood volatile organic aromatic compound concentrations and hearing loss in US adults.

Benzene, ethylbenzene, meta/para-xylene, and ortho-xylene, collectively referred to as benzene, ethylbenzene, and xylene (BEX), constitute the main components of volatile organic aromatic compounds (VOACs) and can have adverse effects on human health. The relationship between exposure to BEX and hearing loss (HL) in the adult U.S. population was aimed to be assessed. Cross-sectional data from the National Health and Nutrition Examination Survey (NHANES) for the years 2003-2004, 2011-2012, and 2015-2016 were analyzed. This dataset included complete demographic characteristics, pure-tone audiometry measurements, and volatile organic compound detection data from the NHANES database. A weighted multivariate logistic regression model was employed to investigate the associations between blood BEX concentrations HL, low-frequency hearing loss (SFHL), and high-frequency hearing loss (HFHL). 2174 participants were included, with weighted prevalence rates of HL, SFHL, and HFHL being 46.81%, 25.23%, and 45.86%, respectively. Exposure to benzene, ethylbenzene, meta/para-xylene, and ortho-xylene, and cumulative BEX concentrations increased the risk of hearing loss (odds ratios [ORs] were 1.36, 1.22, 1.42, 1.23, and 1.31, respectively; all P < 0.05). In the analysis with SFHL as the outcome, ethylbenzene, m-/p-xylene, o-xylene, benzene, and overall BEX increased the risk (OR 1.26, 1.21, 1.28, 1.20, and 1.25, respectively; all P < 0.05). For HFHL, exposure to ethylbenzene, m-/p-xylene, o-xylene, benzene, and overall BEX increased the risk (OR 1.36, 1.22, 1.42, 1.22, and 1.31, respectively; all P < 0.05). Our study indicated that a positive correlation between individual or cumulative exposure to benzene, ethylbenzene, meta/para-xylene, and ortho-xylene and the risk of HL, SFHL, and HFHL. Further research is imperative to acquire a more comprehensive understanding of the mechanisms by which organic compounds, notably BEX, in causing hearing loss and to validate these findings in longitudinal environmental studies.

A Multisensor Device Intended as an IoT Element for Indoor Environment Monitoring.

This work presents a multisensor device which is intended as an element of IoT for indoor environment (IE) monitoring. It is a portable, small-size, lightweight, energy-efficient direct-reading instrument. The device has an innovative design and construction. It offers real-time measurements of a wide spectrum of physical and chemical quantities (light intensity, temperature, relative humidity, pressure, CO2 concentration, content of volatile organic compounds including formaldehyde, NO2, and particulate matter), data storage (microSD; server as an option), transmission (WiFi; GSM and Ethernet as options), and visualization (smartphone application; PC as an option). Commercial low-cost sensors were utilized, which have been arranged in the individual sensing modules. In the case of gas sensors, dynamic exposure was chosen to ensure a minimum response time. The MQTT protocol was applied for data transmission and communication with other devices, as well as with the user. The multisensor device can collect huge amounts of data about the indoor environment to provide the respective information to the IoT. The device can be configured to control actuators of various auxiliary devices and equipment including external systems used for ventilation, heating, and air conditioning. The prototype is fully operational. The exemplary results of IE monitoring were shown.

Volatile Compound Markers in Beef Irradiated with Accelerated Electrons.

This study focuses on the behavior of volatile organic compounds in beef after irradiation with 1 MeV accelerated electrons with doses ranging from 0.25 kGy to 5 kGy to find reliable dose-dependent markers that could be used for establishing an effective dose range for beef irradiation. GC/MS analysis revealed that immediately after irradiation, the chemical yield and accumulation rate of lipid oxidation-derived aldehydes was higher than that of protein oxidation-derived aldehydes. The nonlinear dose-dependent relationship of the concentration of volatile organic compounds was explained using a mathematical model based on the simultaneous occurrence of two competing processes: decomposition of volatile compounds due to direct and indirect action of accelerated electrons, and accumulation of volatile compounds due to decomposition of other compounds and biomacromolecules. A four-day monitoring of the beef samples stored at 4 °C showed that lipid oxidation-derived aldehydes, protein oxidation-derived aldehydes and alkanes as well as alcohol ethanol as an indicator of bacterial activity were dose-dependent markers of biochemical processes occurring in the irradiated beef samples during storage: oxidative processes during direct and indirect action of irradiation, oxidation due to the action of reactive oxygen species, which are always present in the product during storage, and microbial-enzymatic processes. According to the mathematical model of the change in the concentrations of lipid oxidation-derived aldehydes over time in the beef samples irradiated with different doses, it was found that doses ranging from 0.25 kGy to 1 kGy proved to be most effective for beef irradiation with accelerated electrons, since this dose range decreases the bacterial content without considerable irreversible changes in chemical composition of chilled beef during storage.

Optimizing the winemaking process: NIR spectroscopy and e-nose analysis for the online monitoring of fermentation.

In the winemaking process, the rapid determination of specific quality parameters such as sugar content, pH, acidity, concentrations of phenolic compounds, anthocyanins and volatile organic compounds is crucial for high-quality wine production. Traditional analytical methods allow for precise quantification of these parameters but are time-consuming and expensive. This article explores the potential application of non-destructive analytical technique (NDAT) (near infra-red [NIR] and e-nose), as efficient alternatives for online monitoring of fermentation working on two different winemaking tanks and applying chemometrics to develop predictive models to correlate non-destructive and analytical data. NIR measurements have been used to build principal components regression models, showing good prediction capability for polyphenols, anthocyanins, glucose and fructose. Both offline and online e-nose applications demonstrate good capability of discriminating different fermentation phases, in agreement with aromatic profile changes observed via gas chromatography-mass spectrometry analysis. Moreover, correlation analysis reveals the potential of quartz microbalances, Taguchi Gas Sensors and H2 S sensors in predicting the concentration of compounds of great interest for winemaking (e.g. C6 alcohols, ketones, terpenes and ethyl esters) highlighting the robust connection between sensor data and specific chemical classes. This research aims to showcase the potential employment of NDAT for online monitoring the evolution of must composition during fermentation. The proposed methods could potentially fulfil a longstanding requirement of winemakers, enabling them to closely monitor fermentation allowing the timely making of important technical decisions aimed at achieving oenological objectives in wine production. © 2024 Society of Chemical Industry.

Leaching of tire particles and simultaneous biodegradation of leachables

The fate of organic compounds released from tire wear particle (TWP) in the aquatic environment is still poorly understood. This is especially true near sources where biotic and abiotic transformation and leaching from TWP are simultaneous and competing processes. To address this knowledge-gap an experiment was performed, allowing for biodegradation (a) during the leaching from a suspension of cryo-milled tire tread (CMTT) and (b) subsequent to leaching. Besides measuring the Dissolved Organic Carbon (DOC) content, 19 tire-related chemicals were quantified, and non-target screening was performed by LC-HRMS. The non-inoculated control experiment exhibited a DOC of up to 4 mg g−1, with up to 700 µg g−1 of 1,3-diphenylguanidine (DPG) as the most prominent compound, followed by three benzothiazoles (2-mercaptobenzothiazole (2-MBT), 2-hydroxybenzothiazole (2-OHBT) and benzothiazole-2-sulfonic acid (BTSA); 50 µg g−1 each) and 4-hydroxydiphenylamine (4-HDPA) (50 µg g−1). Biodegradation reduced the DOC by 88 % and the concentration of most organic compounds by more than 85 %. At the end of the experiment hexamethoxymethylmelamine (HMMM) was the most prominent single compounds (18 µg g−1). Non-target screening showed a more complex picture. Another 25 transformation products (TPs) of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6-PPD) and 44 TPs and derivatives related to DPG were detected in solution, of which 11 and 28 were still present after or formed by biodegradation, respectively. Of these 39 TPs and derivatives, 31 could be detected in road runoff samples. This study provides a more comprehensive picture of the leachables of tire particles that are of environmental relevance. It also outlines that derivatives of tire additives formed during tire production and use may deserve more attention as leachables. The large extent of biodegradation of tire leachables suggests that settling ponds may be a useful treatment option for road runoff.

Obtaining an important component of humate-enriched organomineral fertiliser based on oxidised lignite from Kyrgyzstan

The study of methods for the production and processing of humateenriched organomineral fertilisers based on oxidised lignite represents a key aspect for modern agriculture, due to the need to improve resource efficiency, soil quality, and sustainability of production. The purpose of this study was to determine the best methods of obtaining and processing humate-enriched organomineral fertilisers based on oxidised lignite. To fulfil this purpose, experimental research was carried out in the laboratory of the Institute of Natural Resources of the Southern Branch of the National Academy of the Kyrgyz Republic and the educational and scientific laboratory of the Department of Ecology and Environmental Protection of the Osh Technological University named after M.M. Adyshev. The findings of the study indicate significant changes in soil characteristics after application of vermicompost and glauconite. Analyses of vermicompost revealed that it has a significant content of nutrient elements and organic compounds. The potassium content of vermicompost increased by 40%, while silicon and phosphorus content increased by 39% and 28.5%, respectively. As a result of vermicomposting, there is an improvement in soil characteristics: pH increases to 7-7.5, organic matter content increases to 35-45%, while C/N-ratio decreases to 10-12, which creates more favourable conditions for plant growth and increases nitrogen use efficiency. After addition of glauconite, an increase in potassium oxide by 0.6%, iron (III) oxide by 2.34%, and aluminium oxide by 0.41% was observed. Silicon oxide content increased by 4.9%, while the content of humic substances – by 1.1%. These changes in soil characteristics contribute to higher yields and better soil quality. The results of the study have practical significance for agriculture in improving soil characteristics, increasing yields and soil quality, and reducing dependence on chemical fertilisers

Water-bridged self-assembly of low-odor xanthate surfactant for selective flotation of chalcopyrite

Xanthate, a high-consumption functional surfactant, poses health and environmental risks due to the presence of volatile sulfides and pungent odors. In this study, we designed a novel ether group enhanced xanthate collector, O-(2-(tert-butoxy)ethyl) xanthate (TBOEX), which exhibits low odor and excellent flotation performance. The high matching between the calculated and the experimental infrared spectrum confirms the existence of water-bridged self-assembly behaviour. Odor evaluation results show that TBOEX reduced the content of volatile sulfur organic compounds and volatile hydrocarbons by 54.2% and 88.6%, respectively, compared to isobutyl xanthate (IBX), effectively reducing odor production. Flotation experiments and Zeta potential measurements demonstrate that TBOEX adsorbs densely on the surface of chalcopyrite, while the rich hydroxide on the surface of pyrite hinders the self-assembly of the collector, resulting in good selectivity for chalcopyrite. DFT calculations further reveal that TBOEX can form a stable and tightly arranged adsorption layer bridged by water molecules on the surface of chalcopyrite through two paths, and interact with d orbitals of copper atoms in the form of Cu-S tetrahedra through π* orbitals, finally improving the flotation recovery of chalcopyrite. The discovery of the water-bridge self-assembly mechanism and interfacial adsorption behavior of TBOEX is expected to drive the targeted design of collectors.

Determination of Volatile Compounds in Blossoms of Rosa spinosissima, Rosa pendulina, Rosa gallica, and Their Cultivars

The aim of our study was to determine how the content and composition of volatile organic compounds (VOCs) change with crossbreeding. We included three autochthonous Slovenian species of roses (R. pendulina, R. spinosissima, and R. gallica) and several cultivars derived from them in the research. The results were compared with the content of the reference plant R. damascena, which is known worldwide for its rich VOC profile and is used in the perfume industry. We found that the total VOC content ranged from 2.579 µg/g FW (‘Fruhlingsmorgen’) to 168.24 µg/g FW (‘Violacea’). According to the content of total VOCs, the variety ‘Charles de Mills’ (43.12 µg/g DM) was the most similar to the variety R. damascena (44.55 µg/g DM). We can conclude that the flowers of the roses we included in the study are a rich source of VOCs. VOC content in hybrids varies depending on the purpose and goals of breeders. We also found that flowering time had no effect on VOC content and composition. With this study, we not only carefully examined the VOC profile of roses but also clearly showed which compounds were present in individual taxa. In this way, it is possible to select a suitable variety or cultivar depending on the desired use, for example, for flavoring food or for a floral fragrance in the perfume industry.

Outdoor trends and indoor investigations of volatile organic compounds in two high schools of southern Italy

AbstractVolatile organic compounds (VOCs) are a class of ubiquitous substances that are present in outdoor and indoor air. They are emitted by a wide range of sources and can penetrate and accumulate specifically in indoor environments. Concern is growing among the scientific community regarding the potential health impacts of exposure to a high concentration of VOCs in indoor spaces. Due to their still-developing respiratory and immune systems, children may be the most fragile subjects in this regard, and therefore, the study of indoor air quality in schools is of the utmost importance. In this work, the concentrations of total volatile organic compounds (TVOCs) and of 20 specific compounds belonging to this class were determined in a school in Squinzano, a town in the province of Lecce (Apulia region, southern Italy). Sampling was carried out in indoor (classrooms and bathrooms) and outdoor (terrace) areas using passive diffusive samplers for VOCs and photoionization detectors for TVOCs. Average concentrations of both TVOC (303 ± 47 µg m−3) and individual VOCs (&lt; 0.5 µg m−3) were below levels of concern; however, specific indoor sources such as cleaning activities and student occupancy were responsible for peaks in TVOC concentrations above harmless levels for children and school staff. The data were then compared to the ones obtained in a similar study conducted in a school in Galatina, another town of the Apulia region, highlighting the impact of the surrounding outdoor environment on the indoor profile of VOCs.

Fluorescence Polarization Assays for Organic Compounds in Food Safety.

Elevated concentrations of toxic organic compounds observed in food products pose serious dangers to human health. Both natural and artificial pollutants can cause food contamination. The stages of food production, packaging, transportation, and storage can also largely cause the appearance of undesirable substances in food products. The health consequences of ingesting food containing toxic contaminants range from mild gastroenteritis to deaths resulting from dysfunctional internal organs and neurological syndromes. The World Health Organization (WHO) sets recommendations for the content of such chemicals in food, including a minimum allowable concentration considered safe for human consumption. However, the control of food products from chemical pollutants is necessary. Moreover, fast, sensitive, and inexpensive methods are needed to detect them at the point of need. Currently, immune analysis methods are most widely used to determine pollutants in food. The development of fluorescence polarization immunoassay (FPIA) methods in a competitive format is a powerful and modern tool for detecting organic molecules in various matrices, thereby making FPIA methods useful for food safety applications. Due to the availability of portable devices for measuring the fluorescence polarization signal, FPIA methods can be used at the point of need. The variety of fluorescent labels and recognizing elements (receptors, monoclonal and polyclonal antibodies, and nanobodies) permits fluorescence polarization (FP) assays to detect significantly lower limits of organic substances. The FP assay is a homogeneous, fast, and quantitative method. The development of various formats of FP assays makes them promising in determining food pollutants. This review summarizes publications on FP analyses for detecting organic contaminants (pesticides, hormones, toxins, antibiotics, and other pharmaceuticals) in food products during 2018-2023. Further, it demonstrates the prospects for using this method to determine pollutants at the point of need and for detecting high molecular weight substances, fungi, and bacterial infections during food safety inspections.

Ambient volatile organic compounds concentration variation characteristics and source apportionment in Lanzhou, China during the COVID-19 lockdown

During the COVID-19 lockdown, PM2.5, ozone and precursor NOx were widely reported, but changes on volatile organic compounds (VOCs) were scarcely reported. It is important to understand the impact of drastic changes in anthropogenic emissions on the levels of VOCs. In this study, VOCs were collected with Summa tank for monitoring before (Period I), during (Period II) and after (Period III) the COVID-19 lockdown in Lanzhou, Northwest China. During the lockdown, the average concentration of VOCs was 49.01 ± 20.63 ppbv, the total mixing ratio was 39.3 % and 48.5 % lower than Period I and Period III, at the same time alkanes, alkenes, aromatics, halo hydrocarbons decreased by 45.5 % and 46.4 %, 20.2 % and 15.1 %, 21.0 % and 51.4 %, 42.9 % and 61.6 %, respectively. The ratio of benzene/toluene (B/T) increased from 0.85 (Period I) to 1.40 (Period II) and finally to 1.83 (Period III). The trend of isobutane to n-butane （IB/NB）was 0.28 (Period I)-0.75 (Period II)-0.92 (Period III). The above results indicated that traffic source contribute more to VOCs in the Period I, and natural gas, coal and biomass combustion are the main sources during the Period II and III. The xylene/ethylbenzene (X/E) ratio showed a tendence higher in the middle (1.42) and lower on both sides (0.78 and 0.57, respectively), which indicated that the aging of gas masses during the lockdown is lower than Period I and III. Five factors resolved by the positive matrix factorization (PMF) model were Liquefied Petroleum Gas (LPG) and vehicle exhaust emission, biomass/coal burning, industrial coatings/solvents, industrial process and gasoline exhaust. The source apportionment calculation consistent with the ratio of B/T and IB/NB showed that the contribution of biomass/coal burning increased from 13.1 % (Period I) to 21.8 % (Period II), while the contribution of LPG and vehicle exhaust emission decreased from 45.8 % to 31.5 %.

Sensitivity of air quality model responses to emission changes: comparison of results based on four EU inventories through FAIRMODE benchmarking methodology

Abstract. Despite the application of an increasingly strict EU air quality legislation, air quality remains problematic in large parts of Europe. To support the abatement of these remaining problems, a better understanding of the potential impacts of emission abatement measures on air quality is required, and air chemistry transport models (CTMs) are the main instrument to perform emission reduction scenarios. In this study, we study the robustness of the model responses to emission reductions when emission input is changed. We investigate how inconsistencies in emissions impact the modelling responses in the case of emission reduction scenarios. Based on EMEP simulations over Europe fed by four emission inventories – EDGAR 5.0, EMEP-GNFR, CAMS 2.2.1 and CAMS version 4.2 (including condensables) – we reduce anthropogenic emissions in six cities (Brussels, Madrid, Rome, Bucharest, Berlin and Stockholm) and two regions (Po Valley in Italy and Malopolska in Poland) and study the variability in the concentration reductions obtained with these four emission inventories. Our study reveals that the impact of reducing aerosol precursors on PM10 concentrations result in different potentials and potencies, differences that are mainly explained by differences in emission quantities, differences in their spatial distributions as well as in their sector allocation. In general, the variability among models is larger for concentration changes (potentials) than for absolute concentrations. Similar total precursor emissions can, however, hide large variations in sectorial allocation that can lead to large impacts on potency given their different vertical distribution. Primary particulate matter (PPM) appears to be the precursor leading to the major differences in terms of potentials. From an emission inventory viewpoint, this work indicates that the most efficient actions to improve the robustness of the modelling responses to emission changes would be to better assess the sectorial share and total quantities of PPM emissions. From a modelling point of view, NOx responses are the more challenging and require caution because of their non-linearity. For O3, we find that the relationship between emission reduction and O3 concentration change shows the largest non-linearity for NOx (concentration increase) and a quasi-linear behaviour for volatile organic compounds (concentration decrease). We also emphasise the importance of accurate ratios of emitted precursors since these lead to changes in chemical regimes, directly affecting the responses of O3 or PM10 concentrations to emission reductions.

Effect of spraying air freshener on particulate and volatile organic compounds in vehicles

People in these days spend approximately 6 % of their time in a means of transport. Air fresheners are frequently used in vehicles to mask odors; however, they can cause adverse health effects such as cardiovascular disease, systemic inflammation and autonomic dysfunction. This study aimed to identify the effects of air fresheners on the concentrations of particulate and volatile organic compounds (VOCs) in different vehicle cabins. Scanning mobility and optical particle sizers were used for the particle measurements. VOCs (e.g., BTEX and d-limonene) were collected using a Tenax TA. The products were sprayed for less than a minute. The study assessed three spray products (all trigger types), vehicle size (small, medium, and large), cabin temperature (10 °C, 20 °C, and 25 °C), and in-vehicle ventilation mode (all-off, recirculation, and external inflow modes). The particle concentration increased rapidly during the 1-min spraying of the products. The proportion of nanoparticles in the front seat (67.2 % ± 2.2 %) was 11.1 % ± 2.2 % lower than that in the rear seat (75.6 % ± 2.1 %). The spray product and vehicle size did not significantly affect the particle or VOC concentrations. With an increase in the temperature of the front seat, the proportion of nanoparticles increased by 25.3 % ± 3.2 %. Moreover, the maximum total VOC concentrations (front seat: 364.3 μg/m3; back seat: 241.3 μg/m3) were observed at 20 °C. Under in-vehicle ventilation, recirculation effectively reduced the overall particle concentration within the cabin; however, the generated VOCs circulated. The external inflow proved effective in cabin air purification by reducing the total VOC concentration to 56.0–57.2 % compared with other ventilation modes. These findings provide substantial insight into the persistence of particles and the dynamics of their dispersion, thereby enabling informed decision-making for particle-related risk management.

Improvement of ferrioxalate assisted Fenton and photo-Fenton processes for paracetamol degradation by hydrogen peroxide dosage.

This work aimed to investigate the impact of hydrogen peroxide (HP) punctual dosage on paracetamol (PCT) degradation, through Fenton and photo-Fenton processes under near-neutral pH conditions, using ferrioxalate and artificial sunlight. The assays were performed using a D-optimal experimental design, to statistically evaluate the influence of radiation (ON or OFF), HP concentration (94.5-756mg L-1), and HP dosage (YES or NO), on PCT conversion. The optimal conditions determined from the study were: HP = 378mg L-1, DOS = YES, and RAD = ON, achieving a predicted PCT conversion of 99.68% in 180min. This result obtained from the model was very close to the experimental one (98.80%). It was verified that HP dosage positively influenced the iron catalytic cycle since higher Fe2+ concentrations were reached at shorter reaction times, accelerating not only PCT conversion but also its by-products hydroquinone and 1,4-benzoquinone, leading to better performances of Fenton and photo-Fenton reactions. Under optimal conditions and employing real water matrices (an artificial matrix with inorganic anions, a real groundwater sample, and a synthetic industrial wastewater), HP dosage demonstrated the ability to mitigate the negative effects caused by the content of different ions and other organic compounds and significantly improve HP consumption in challenging wastewater conditions.

Assessment of Atmospheric Pollution by Selected Elements and PAHs during 12-Month Active Biomonitoring of Terrestrial Mosses

Biomonitoring studies are most often used in short-term study periods to quickly obtain information on the state/quality of the environment and its pollution levels. Performing long-term surveys involves a prolonged wait for the result and is therefore not often used and is rather associated with classical air quality monitoring. The aim of this study was to evaluate atmospheric air pollution by selecting 16 elements and 16 polycyclic aromatic hydrocarbons conducted as part of a 12-month ‘moss-bag’ technique of an active biomonitoring method with the use of three moss species: Pleurozium schreberi, Sphagnum fallax, and Dicranum polysetum. All analytes were determined by inductively coupled plasma mass spectrometry (ICP-MS) and gas chromatography–mass spectrometry (GC-MS). As a result of the experiment, it was found that the concentrations of all elements increased with time of exposure. The total sum of them in D. polysetum moss was 30% and 60% more than in P. schreberi and S. fallax, respectively, which allows us to consider this species’ broader use in active biomonitoring. For PAHs analysis, the best biomonitor in time was P. schreberi, which accumulated 25% and 55% more than S. fallax and D. polysetum, respectively. In this one-year study, most organic compounds accumulated between 5 and 6 months of exposure, depending on the species. Given the low-cost nature of active biomonitoring, it should be concluded that mosses could be used in long-term monitoring of the quality of the atmospheric aerosol in terms of element and organic compound concentration in air.