Volatile Organic Matter Research Articles

A closed-loop sustainable method for the fabrication of electrospun nanofiber using food waste for filtration of particulate matters (PMs) and volatile organic matter (VOCs) from air

Indoor air pollution significantly impacts human health and the environment. Humans suffer the greatest health burden due to inefficient combustion technologies and polluted fuels. Therefore, air filtration is essential for a healthy and prosperous household. This study aims to develop a sustainable approach for the fabrication of biodegradable electrospun nanofibers (ENs) as air filters from food waste materials and offer a closed-loop circular solution and potential replacement for non-biodegradable HEPA air filters. We have tested banana peel extract (BPE), eggshell membrane, chitosan, and starch blended with polyvinyl alcohol (PVA) for fabricating ENs. Among the nanofibers investigated for air filtration application, BPE/PVA nanofiber shows the best performance in terms of maximum particulate matter (PM) removal efficiency and minimum pressure drop while incorporating > 50% of the food waste into the electrospinning solution. Adding BPE into a 10% PVA solution leads to a reduction in the hydrophilic behavior of the BPE/PVA nanofiber as compared to neat 10% PVA ENs. The BPE/PVA nanofiber shows minimum pressure drop (156–160 Pa) and highest quality factor (Qf) in comparison with other waste-derived nanofibers with > 98% filtration efficiency of PM2.5. Further, BPE/PVA nanofiber shows the highest adsorption of xylene vapor among other food waste derived nanofibers studied. Based on the above results, it can be concluded that BPE based nanofiber shows the best performance as air filter media among all other food waste-based ENs. The study demonstrates a successful regeneration and reuse of the BPE/PVA filter up to 3 cycles. The leftover material from banana peels after BPE extraction was utilized as a soil ameliorant. It showed 55% soil water retention (SWR) capacity, making it possible to apply in arid regions or crops with high water requirements.

A novel method for real-time inhalation toxicity assessment in mice using respirometric system: A promising tool for respiratory toxicology

Inhalation toxicity assessment is a crucial tool for the identification and classification of hazardous materials like volatile organic carbons, aerosols, and particulate matter. Unlike traditional acute inhalation toxicity studies that use mortality as an endpoint, the Fixed Concentration Procedure (FCP) emphasizes "evident toxicity" by monitoring behavior, weight, and food intake. This reduces reliance on mortality but doesn't directly address respiratory system impact. The present study introduced a respirometer-based inhalation toxicity and respiratory status assessment method. The toxicity evaluation system integrated a respirometric system with an animal exposure chamber, enabling real-time monitoring of oxygen consumption. The ICR mice were exposed to various concentrations of benzene (10, 20, 40, and 80 mg/L of air), toluene (7.5, 15, 30, and 60 mg/L of air), and xylene (7.5, 15, 30, and 60 mg/L of air). The respiration rate decreased by 70 % and 69 % for benzene (80 mg/L of air) and toluene (60 mg/L of air), respectively, with EC50 values of 32.5 mg/l and 21.2 mg/L based on oxygen consumption. Xylene did not exhibit EC50 values at the tested concentrations. However, the oxygen consumption rate significantly decreased (46 %) at high concentrations (60 mg/L of air), indicating sub-lethal toxicological effects. Furthermore, the present study was also validated in the bleomycin-induced idiopathic pulmonary fibrosis (IPF) model, demonstrating its reliability as a respiratory impairment marker. The results exhibited a strong correlation between weight loss and less oxygen consumption in the BLM group (bleomycin-induced) as compared to the SHAM group (control), which was confirmed by histological examination and protein marker analysis. The results suggest the potential use of oxygen consumption as an endpoint measurement in inhalation toxicity assessment tests without animal sacrifice, and the present study could be useful for providing valuable insights into disease progression and pharmacological interventions.

Sources and determinants of exposure to indoor air pollutants in schools and hospitals: a review

Abstract Background Indoor Air Quality (IAQ) is an important determinant of health. This study aimed to review the available scientific evidence about indoor pollutants and determinants of exposure in several settings, in the scope of the K-HEALTHinAIR project. Methods The systematic review was performed for the sources, concentrations, and determinants of pollutants in schools in the European region for 2013-2023. Articles were selected for data extraction if they were epidemiological studies, reported primary data for indoor air and pollutant levels, and, identified sources and determinants of exposure. Results The main pollutants affecting IAQ in schools and hospitals were carbon dioxide, volatile organic compounds (e.g., formaldehyde, terpenes), particulate matter, nitrogen dioxide, radon, ozone, and carbon monoxide. Besides the outdoor environment, several important indoor sources of emissions were identified such as occupancy, resuspension, cleaning products. Ventilation was the main determinant influencing the indoor levels of pollutants, stressing the importance of good planning, installation, and maintenance of mechanical ventilation systems in buildings. Other determinants were the number of occupants and their activities, and the building characteristics (e.g., type of floor, location, etc). Conclusions Results revealed indoor air quality as a public health concern since several pollutants are present in indoor settings. The identification of sources and determinants of exposure is fundamental for determining preventive measures in a public health perspective. Acknowledgments: K-HEALTHinAIR team for screening and data extraction: Mariana Corda, Jose Fermoso, Alicia Aguado, Sandra Rodriguez, Hanns Moshammer, Mireia Ferri, Belén Costa, Leticia Pérez, Wojciech Hanke, Artur Badyda, Piotr Kepa, Katarzyna Affek, Nina Doskocz, Laura Martín, Oguz Mulayim, Cesar Mediavilla Martinez, Alba Gómez, Ruben González, Isaac Cano, Josep Roca, Simon de Leede.

Evaluating the impacts of printing operations on indoor air quality in a printing press

PurposeBuilding operations and human activities indoors continuously affect air quality, contaminating the air and sometimes exceeding permissible limits which can be health threatening either in the short or long time. This implies a need for strict awareness and compliance with air quality standards, particularly in workplaces prone to air contaminants emissions. This study aims to evaluate printing-related pollutant concentrations and their effects on indoor air quality (IAQ). The study investigated a printing press's total volatile organic compounds (TVOC), particulate matter (PM), carbon monoxide and carbon dioxide emissions.Design/methodology/approachThis study used mainly an experimental research design supported by physical assessment by identifying the major printing-related pollutants, assessing the existing situation and measuring pollutant concentration levels using literature reviews, walkthrough inspections and experiments, respectively. The measurements were conducted in two scenarios: with and without printing activities, and the results were compared with relevant standards and guidelines.FindingsThe outcomes indicate that TVOC concentration reaches 120 ppb during printing and binding activities, exceeding the 75 ppb acceptable limit based on the time-weighted average. The PM2.5 concentrations reach 49 µg/m3 and PM10 up to 150 µg/m3, exceeding acceptable levels given by the US Environmental Protection Agency (EPA), which are 35 µg/m3 and 150 µg/m3 for PM2.5 and PM10, respectively. These high concentrations of TVOC and PM indicate a significant risk to the health of building occupants, particularly those with respiratory conditions. PM concentrations do not exceed permissible levels when no printing or bookbinding occurs, suggesting that printing-related activities can contribute to elevated TVOC and PM concentrations.Social implicationsThe social implication of the study lies in its ability to promote awareness among workers and improve their well-being which in turn relates to productivity. The study outcome could also encourage businesses to adopt more responsible environmental and social practices as part of corporate social responsibility practices.Originality/valueThe study's findings, which highlight the need for improved ventilation in printing halls, have the potential to significantly benefit building system designers, facility managers, policymakers and decision-makers. By providing information and theoretical support, the research can help integrate policies that regulate IAQ by reducing pollutant concentrations. This protects workers' health and helps update and enforce stricter IAQ regulations for industrial operations.

Biomass-burning sources control ambient particulate matter, but traffic and industrial sources control volatile organic compound (VOC) emissions and secondary-pollutant formation during extreme pollution events in Delhi

Abstract. Volatile organic compounds (VOCs) and particulate matter (PM) are major constituents of smog. Delhi experiences severe smog during the post-monsoon season, but a quantitative understanding of VOCs and PM sources is still lacking. Here, we conduct a source apportionment study for VOCs and PM using a recent (2022), high-quality dataset of 111 VOCs, PM2.5, and PM10 in a positive matrix factorization (PMF) model. Contrasts between clean monsoon air and polluted post-monsoon air, VOC source fingerprints, and molecular tracers enabled us to differentiate paddy residue burning from other biomass-burning sources, which had previously been impossible. Burning of fresh paddy residue, as well as residential heating and waste burning, contributed the most to observed PM10 levels (25 % and 23 %, respectively) and PM2.5 levels (23 % and 24 %, respectively), followed by heavy-duty vehicles fuelled by compressed natural gas (CNG), with a PM10 contribution of 15 % and a PM2.5 contribution of 11 %. For ambient VOCs, ozone formation potential, and secondary-organic-aerosol (SOA) formation potential, the top sources were petrol four-wheelers (20 %, 25 %, and 30 %, respectively), petrol two-wheelers (14 %, 12 %, and 20 %, respectively), industrial emissions (12 %, 14 %, and 15 %, respectively), solid-fuel-based cooking (10 %, 10 %, and 8 %, respectively), and road construction (8 %, 6 %, and 9 %, respectively). Emission inventories tended to overestimate residential biofuel emissions at least by a factor of 2 relative to the PMF output. The major source of PM pollution was regional biomass burning, while traffic and industries governed VOC emissions and secondary-pollutant formation. Our novel source apportionment method even quantitatively resolved similar biomass and fossil fuel sources, offering insights into both VOC and PM sources affecting extreme pollution events. This approach represents a notable advancement compared to current source apportionment approaches, and it could be of great relevance for future studies in other polluted cities and regions of the world with complex source mixtures.

The effect of different climate and air quality policies in China on in situ ozone production in Beijing

Abstract. In recent years, clean air policies have led to reductions in air pollution across China. Alongside this, emerging carbon neutrality (CN) policies that aim to address the impacts of climate change may also deliver air quality (AQ) co-benefits or climate penalties. Different CN policies will lead to different changes in volatile organic compound (VOC), NOx and particulate matter (PM) emissions, which will in turn impact the photochemical production of secondary pollutants such as ozone (O3). It is currently unclear how different combinations of AQ and CN policies may impact in situ O3 production across China in the future. A detailed chemical box model incorporating the Master Chemical Mechanism was developed to investigate the impact of combined AQ and CN policies on O3 formation in Beijing. The Multi-resolution Emission Inventory model for Climate and air pollution research (MEIC) and the Dynamic Projection model for Emissions in China (DPEC) were used to estimate future pollutant mixing ratios, relative to ambient observations of 35 VOCs, NOx, CO and aerosol surface area (ASA) during the APHH-Beijing 2017 summer campaign. The most ambitious policy scenario, “Ambitious Pollution 1.5D Goals”, led to the largest reduction in O3 production by 2060 but was not the most impactful scenario for reducing O3 production between 2030–2045. Larger reductions were observed under the “Ambitious Pollution Neutral Goals” policy, which focuses on achieving net zero by 2060. O3 production was found to be most sensitive to changes in the OLE2 group of VOCs (alkenes where kOH>7×104 ppm−1 min−1; a 5 % increase in OLE2 increased simulated O3 production by 1.12 %). However, reducing less reactive but higher concentration species in Beijing (such as short-chain alkanes) led to larger reductions in O3 production under all scenarios. O3 production was not sensitive to changes in ASA, with a 69 % decrease in ASA leading to a change of <1 % in O3. However, doubling biogenic VOCs in the model further increased O3 production in 2060 under all future scenarios by up to 18 %, indicating that the influence of future climate-induced changes in biogenic emissions may have a significant impact on in situ O3 formation in Beijing. This study highlights that the emission trajectories of certain specific VOCs are highly influential in determining possible future O3 air quality effects that may arise from increasing ambient temperatures and decarbonisation in Beijing.

Comprehensive analysis of classroom microclimate in context to health-related national and international indoor air quality standards.

Indoor air quality (IAQ) and indoor air pollution are critical issues impacting urban environments, significantly affecting the quality of life. Nowadays, poor IAQ is linked to respiratory and cardiovascular diseases, allergic reactions, and cognitive impairments, particularly in settings like classrooms. Thus, this study investigates the impact of indoor environmental quality on student health in a university classroom over a year, using various sensors to measure 19 environmental parameters, including temperature, relative humidity, CO2, CO, volatile organic compounds (VOCs), particulate matter (PM), and other pollutants. Thus, the aim of the study is to analyze the implications of the indoor microclimate for the health of individuals working in the classroom, as well as its implications for educational outcomes. The data revealed frequent exceedances of international standards for formaldehyde (HCHO), VOC, PM2.5, NO, and NO2. HCHO and VOCs levels, often originating from building materials and classroom activities, were notably high. PM2.5 levels exceeded both annual and daily standards, while NO and NO2 levels, possibly influenced by inadequate ventilation, also surpassed recommended limits. Even though there were numerous exceedances of current international standards, the indoor microclimate quality index (IMQI) score indicated a generally good indoor environment, remaining mostly between 0 and 50 for this indicator. Additionally, analyses indicate a high probability that some indicators will exceed the current standards, and their values are expected to trend upwards in the future. The study highlighted the need for better ventilation and pollutant control in classrooms to ensure a healthy learning environment. Frequent exceedances of pollutant standards can suggest a significant impact on student health and academic performance. Thus, the present study underscored the importance of continuous monitoring and proactive measures to maintain optimal indoor air quality.

Dairy wastewater treatment with direct-contact membrane distillation in Oman

Direct contact membrane distillation (DCMD) process was implemented for treating dairy wastewater (DWW) from an Omani dairy industry. Commercial polytetrafluoroethylene (PTFE) and polypropylene (PP) membranes were tested under different temperatures. The aim of this study in to investigate the potential of pure water production rejecting salts, volatile and non-volatile organic compounds present in DWW. Using laboratory techniques such as gas chromatography, we inspected permeate composition, identifying both volatile and non-volatile organic matter. Comprehensive characterization of membrane surface properties via Fourier-transform Infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and Thermal Gravimetric analysis (TGA) provided critical insights. Findings revealed the denaturation of proteins at 60 °C, leading to significant pore blockage and a consequential 50.3 % reduction in flux. Impressively, the membranes achieved rejection rates of 89–99 % for non-volatile organic matter, while completely rejecting D-limonene. However, traces of volatile fatty acids were detected in the permeate. Elemental analysis exposed the presence of various dairy-derived elements at the membrane surface. FTIR peaks highlighted distinct functional groups of dairy components, while TGA affirmed the accumulation of dairy aggregates with rising temperature. These findings underscore membrane distillation's competence in dairy wastewater treatment, presenting a compelling case for its widespread application in environmental remediation endeavors.

Air quality assessment of poultry and swine houses in Chonburi Province

ABSTRACT The increased consumption of animal products has led to a proliferation of animal husbandry operations, particularly in agricultural countries. Animal husbandry facilities or livestock farming directly impact the physical, chemical, and biological aspects of the environment, giving rise to various issues such as odors, contamination of water and air sources with pathogens, and potential contamination of meat products originating from these facilities. This research aims to assess the impacts on the physical (temperature, relative humidity and air velocity), chemical (carbon dioxide, total volatile organic compounds and particulate matter), and biological air quality assessment (amount and type of bioaerosols) aspects resulting from pig and poultry farming. The findings will serve as valuable data for managing and addressing these aforementioned issues. It was found that both in poultry and swine houses generated total suspended particles (TSP) and PM10 (Particulate Matter with a diameter of 10 µm or less). Analysis of poultry house exhaust revealed elevated concentrations of TSP and PM10 exceeding established health benchmarks. Chickens tend to produce a higher concentration of VOCs (2.07 ± 0.57 ppm) compared to swine (0.82 ± 0.53 ppm). Staphylococcus epidermidis was predominant bacteria in both swine and poultry houses while Cladosporium sp was the most prevalent fungi in poultry houses. These results in this study are very useful for developing targeted mitigation strategies, products, devices to address specific pollutants produced by each type of livestock, reducing overall environmental impact and improving air quality within and around animal husbandry facilities. Implications: This research highlights how the growing demand for meat is affecting the environment, especially in farming areas. By studying the effects of pig and poultry farming on things like air and water quality, the study shows the challenges these farms pose, like bad smells and pollution. They found that both types of farms release a lot of tiny particles and smelly chemicals into the air, but there are differences between them. Understanding these findings can help us develop ways to reduce the pollution from these farms and make the air cleaner for everyone.

Optimizing photocatalytic performance in an electrostatic-photocatalytic air purification system through integration of triboelectric nanogenerator and Tesla valve

Increasing the collision frequency between gas molecules and photocatalysts can enhance the removal efficiency of volatile organic compounds (VOCs) and particulate matter (PM) in air. In this study, we propose an Electrostatic-Photocatalytic air purification system, containing Tesla valve, triboelectric nanogenerator (TENG), and photocatalysis parts. The incorporation of Ag@ZnO nanorod array (Ag@ZnO-NR) photocatalysts into the internal baffles of the Tesla valve pipeline effectively enhances the collision probability between air pollutant molecules and photocatalysts, and thus facilitating the removal efficiency of pollutants. Additionally, the high-voltage electricity (∼9.0 kV) generated by the TENG facilitates the separation of electron-hole pairs in the photocatalyst, leading to increased production of superoxide radicals (O•−2), hydroxyl radicals (•OH), and holes (h+), thereby enhancing the photocatalytic efficiency. In a 1.8 L space system, we achieved an approximately 97 % removal efficiency for toluene within 130 minutes and a similar efficiency for formaldehyde (∼200 ppm) within 175 minutes. Additionally, the PM2.5 concentration rapidly decreased from 999 μg·m−3 to 42 μg·m−3 within 6 minutes, alongside with a significantly faster pollutant removal rate compared to conventional methods. By integrating Tesla valves, TENG, and photocatalysis, this combined system presents an efficient and promising approach for addressing indoor air pollution, with potential applications across various settings.

IoT-based monitoring system and air quality prediction using machine learning for a healthy environment in Cameroon.

This paper is aimed at developing an air quality monitoring system using machine learning (ML), Internet of Things (IoT), and other elements to predict the level of particulate matter and gases in the air based on the air quality index (AQI). It is an air quality assessor and therefore a means of achieving the Sustainable Development Goals (SDGs), in particular, SDG 3.9 (substantial reduction of the health impacts of hazardous substances) and SDG 11.6 (reduction of negative impacts on cities and populations). AQI quantifies and informs the public about air pollutants and their adverse effects on public health. The proposed air quality monitoring device is low-cost and operates in real-time. It consists of a hardware unit that detects various pollutants to assess air quality as well as other airborne particles such as carbon dioxide (CO2), methane (CH4), volatile organic compounds (VOCs), nitrogen dioxide (NO2), carbon monoxide (CO), and particulate matter with an aerodynamic diameter of 2.5 microns or less (PM2.5). To predict air quality, the device was deployed from November 1, 2022, to February 4, 2023, in certain bauxite-rich areas of Adamawa and certain volcanic sites in western Cameroon. Therefore, machine learning algorithm models, namely, multiple linear regression (MLR), support vector regression (SVR), random forest regression (RFR), XGBoost (XGB), and K-nearest neighbors (KNN) were applied to analyze the collected concentrations and predict the future state of air quality. The performance of these models was evaluated using mean absolute error (MAE), coefficient of determination (R-square), and root mean square error (RMSE). The obtained data in this study show that these pollutants are present in selected localities albeit to different extents. Moreover, the AQI values obtained range from 10 to 530, with a mean of 132.380 ± 63.705, corresponding to moderate air quality state but may induce an adverse effect on sensitive members of the population. This study revealed that XGB regression performed better in air quality forecasting with the highest R-squared (test score of 0.9991 and train score of 0.9999) and lowest RMSE (test score of 1.5748 and train score of 0. 0073) and MAE (test score of 0.0872 and train score of 0.0020), while the KNN model had the worst prediction (lowest R-squared and highest RMSE and MAE). This embryonic work is a prototype for projects in Cameroon as measurements are underway for a national spread over a longer period of time.

Separation processes for the treatment of industrial flue gases – Effective methods for global industrial air pollution control

The treatment of flue gases has become a crucial area of interest with the increasing air emissions into the atmosphere from industries involved in combustion of fossil fuels in their operations. In essence, there is a critical need for effective methods of treatment more than ever. Treatment and separation are now a demand for the overall industrial operations to control the rate of flue gas emissions. The major culprit in this wise is power generating industry. The major associated air pollutants are carbon dioxide, sulfur oxides, trace metals, volatile organic compounds, particulate matters, and nitrogen oxides. However, the choice of technologies to be utilized requires more than just knowledge of the separation process, but also a good understanding of the properties of the pollutants. This review explored and evaluated the various separation processes and technologies for the treatment of industrial flue gases for the control of the associated air pollutants. It also analyzed the performance with references to cost and efficiency, the advantages and disadvantages, principles for selection, research direction, and/or potential opportunities in existing separation processes and technologies.

Evaluating the Performance and Practicality of a Multi-Parameter Assessment System with Design, Comparative Analysis, and Future Directions

This study introduces a developed environmental quality assessment system, detailing its hardware, software, and comparative analysis against a publicly available system. While showing larger deviations in particulate matter and air humidity parameters, the proposed system demonstrates sufficient accuracy in other environmental characteristics. It establishes a standardized operating procedure and evaluates uncertainty and quality assurance measures, ensuring reliability in environmental measurements. The system offers comprehensive capabilities, measuring parameters like total volatile organic compounds, carbon dioxide, temperature, humidity, particulate matter, noise, nitrogen oxides, sulfur oxides, ozone, and carbon monoxide, with real-time monitoring functions for detecting environmental changes. Its user-friendly interfaces, scalability, and potential integration with existing systems enhance its versatility and cost-effectiveness across diverse settings. This study underscores the need for future research to enhance accuracy, reliability, and real-time operability and explore integration with smart city initiatives and environmental management systems. Overall, the proposed system represents a promising advancement in environmental monitoring technology, facilitating comprehensive environmental quality assessment and management.

Advancing biohydrogen production from organic fraction of municipal solid waste through thermal liquefaction

The study aims to examine the sustainability assessment within the circular bioeconomy of biohydrogen production from separated biomass from municipal solid waste (MSW). Successive biohydrogen production from the organic fraction of municipal solid waste (OFMSW) was deployed using hydrothermal liquefication in an innovative small-scale biorefinery system. The biomass was separated by the municipal solid and was dried, shredded, grinded and chopped before conversion. The feedstock was mixed with nickel oxide (5 % w/w) and saturated in distilled water with an 85 % volume-to-mass ratio. Temperature (200–400 °C) and pressure (7–25 MPa) were provided for a retention time of about 60 min with regular agitation. The optimization of parameters produced 207.3 kg of biohydrogen and 17.5 L of bio-oil, respectively. The economic assessment results revealed the feasibility of biohydrogen production with a total revenue of 13,669.02 $ per day and 306,718.4 $ in a month of 22 working days in a single shift of 8 h. The internal cost, capital sum (5,374,575.5 $) and operation cost (169,680.5 $) were calculated to 848,022.7 $. Notably, the top environmental impact emissions were recorded, such as carbon dioxide (CO2), methane (CH4), nitrogen oxides (NOx), carbon monoxide (CO), Non-methane volatile organic compound (NMVOC), particulate matter (PM), and sulfur dioxide with total external cost of 9.15 $. Thus, the life cycle costing was calculated at 848,031.84 $. The economic assessment revealed that photovoltaic energy instead of grid-mix energy reduces the environmental dilemma as Fine particulate matter formation from 0.25 kg PM2.5 eq. to 0.05 kg PM2.5 eq., Terrestrial ecotoxicity from 75.8 kg 1,4-DB eq. to 17.2 kg 1,4-DB eq., and Ionization radiation from 0.22 kBq Co-60 eq. to air to 0.06 kBq Co-60 eq. to air. Thus, it is proven that biohydrogen production from organic fraction of municipal solid waste is a win-win-win situation.

Microalgal biochar assisted simultaneous removal of particulate matter, formaldehyde, and total volatile organic compounds (TVOC's) from indoor air

Biochar-based materials for air treatment have gained significant attention for removing health-detrimental volatile organic compounds (VOCs) and particulate matter (PM) in indoor air settings. However, high turnaround time, multiple pretreatment processes involved, and high pore size and low surface area (>10 μm, <100 m2 g−1) of lignocellulosic feedstocks demand alternative biochar feedstock material. Considering this, we designed a simple first-of-its-kind indoor air scrubbing material using diatoms-enriched microalgae biochar. In the present study, the microalgae were cultivated on waste anaerobic digestate (biogas slurry) and were pyrolyzed at three different temperatures: 300 °C (BC300), 500 °C (BC500), and 700 °C (BC700). The BC500 and BC700 showed the highest removal efficiencies (99 %) for total volatile organic carbons (TVOCs) and formaldehyde (HCHO) at concentrations of 1.22 mg m−3 HCHO and 8.57 mg m−3 TVOC compared to 50% efficiency obtained with commercially available surgical, cloth, and N95 masks. The biochar obtained showed a high Brunauer–Emmett–Teller (BET) surface area of 238 m2 g−1 (BC500) and 480 m2 g−1 (BC700) and an average pore size of 9–11 nm due to the mesoporous characteristic of diatom frustules. The comparatively poor performance of BC300 was due to lower surface area (150 m2 g−1) arising from incomplete organic removal, as evidenced by FESEM-EDX and FTIR. The high removal efficiencies in BC500 and BC700 were also attributed to the presence of reactive functional groups such as –OH and R–NH2. Concurrently, the average particulate matter (PM10, PM2.5, and PM1) removal efficiency for BC500 and BC 700 ranged between 66 and 82.69 %. The PM removal performance of BC500 and BC700 was lower (15–20%) than commercially available masks. Overall, the present study highlights the importance of diatoms (reactive Si) present inside the pores of microalgal biochar for enhanced removal of PM, TVOCs, and HCHO at temperatures above 500 °C. This complete approach signifies a step towards establishing a self-sustainable and circular process characterized by minimal waste generation for indoor air treatment.

Association of exposure to indoor molds and dampness with allergic diseases at water-damaged dwellings in Korea

This study aims to characterize levels of molds, bacteria, and environmental pollutants, identify the associations between indoor mold and dampness exposures and childhood allergic diseases, including asthma, allergic rhinitis, atopic dermatitis, using three different exposure assessment tools. A total of 50 children with their parents who registered in Seoul and Gyeonggi-do in Korea participated in this study. We collated the information on demographic and housing characteristics, environmental conditions, and lifestyle factors using the Korean version of the International Study of Asthma and Allergies in Childhood questionnaire. We also collected environmental monitoring samples of airborne molds and bacteria, total volatile organic compounds, formaldehyde, and particulate matter less than 10 µm. We evaluated and determined water damage, hidden dampness, and mold growth in dwellings using an infrared (IR) thermal camera and field inspection. Univariate and multivariate regression analyses were performed to evaluate the associations between prevalent allergic diseases and exposure to indoor mold and dampness. Indoor mold and bacterial levels were related to the presence of water damage in dwellings, and the mean levels of indoor molds (93.4 ± 73.5 CFU/m3) and bacteria (221.5 ± 124.2 CFU/m3) in water-damaged homes were significantly higher than those for molds (82.0 ± 58.7 CFU/m3) and for bacteria (152.7 ± 82.1 CFU/m3) in non-damaged dwellings (p < 0.05). The crude odds ratios (ORs) of atopic dermatitis were associated with < 6th floor (OR = 3.80), and higher indoor mold (OR = 6.42) and bacterial levels (OR = 6.00). The crude ORs of allergic diseases, defined as a group of cases who ever suffered from two out of three allergic diseases, e.g., asthma and allergic rhinitis, and allergic rhinitis were also increased by 3.8 and 9.3 times as large, respectively, with water damage (+) determined by IR camera (p < 0.05). The adjusted OR of allergic rhinitis was significantly elevated by 10.4 times in the water-damaged dwellings after adjusting age, sex, and secondhand smoke. Therefore, a longitudinal study is needed to characterize dominant mold species using DNA/RNA-based sequencing techniques and identify a causal relationship between mold exposure and allergic diseases in the future.

Driver Education and Awareness of In-Vehicle Air Pollutants and Health

Background: The confined space of vehicle cabins exposes drivers and passengers to high levels of pollutants such as carbon monoxide (CO), volatile organic compounds (VOCs), carbon dioxide (CO2) and particulate matter (PM). Rising levels of in-vehicle air pollutants in public transport are of public health concern in sub-Saharan Africa. This study explores the educational levels of commercial vehicle drivers and their association with in-vehicle pollution. Methods: Employinga mixed-method approach, the study utilized a self-administered questionnaire and air pollutant exposure monitors. Purposive sampling selected 89 drivers and corresponding 89 passengers of vehicles that travel an average of 1 hour per trip. Logistic models and non-parametric tests were used for statistical analyses.Results: Findings show that CO and PM are common in-vehicular air pollutants at different levels across diverse compartments in a vehicle. In addition, 64% of drivers had formal education up to the senior high school level. Breathlessness and coughing were respiratory symptoms common among drivers with a low level of education compared to their highly educated counterparts. Moreover, drivers had limited knowledge of the negative impact of in-vehicular air pollutants on respiratory health. Drivers predominantly associated pollution with exhaust emissions.Conclusion: The pivotal role of formal education in mitigating in-vehicle air pollution is emphasized by the study. It advocates for intensified driver education initiatives that result in the protection of both drivers and passengers from the health risk of pollution.

Lab-scale environmental impact measurement of polymer-modified asphalt concrete mixtures production

This study aims to evaluate and compare the environmental impact of producing numerous polymer-modified asphalt concrete mixture types for road structures at the laboratory scale measured by air quality monitoring devices in a designed isolated area. Several mixture combinations were examined in this study, namely between the production of the standard hot mix at 160oC (case 1) and polymer-modified warm mix asphalt with 5% and 6% polymer dosages at 130oC (case 2 and case 3), as well as the production of hot mix asphalt using polymer modification by wet mix - known as polymer modified binder/PMB at 180oC (case 4) and dry mix methods using 5% and 6% polymer dosages at 160oC (case 5 and case 6), with each case represented by five samples fabrication. Case 4 yields the highest carbon dioxide, the volatile organic compound (VOC), formaldehyde (HCHO), and particulate matter (PM10 and PM1) by a total of 8195ppm, 10.12ppm, 6.5ppm, 1643 µg/m3, and 838 µg/m3, respectively, except PM2.5, where the outcome of case 3 is 1.2% higher than case 4. Meanwhile, the lowest emissions are recorded for case 2 and case 5, with the ratio to case 4 ranging from 43.5% to 96.5%. The heating phase generally gives the highest contribution to the total result, with the proportion ranging from 43.5% for carbon dioxide to above 90% for particulate matter. To sum up, producing hot mix asphalt with PMB and the mixer blending stage generates the highest emission.

Gas-liquid contact evaporation of concentrate leachate from disk-tube reverse osmosis treatment in waste incineration plant

In order to utilize waste heat such as exhaust steam and hot air passing through air preheater in the waste incineration plant to heat air used for evaporating leachate concentrate (LC) by gas-liquid contact evaporation technology, hot air of 600 °C, 450 °C and 250 °C was used to evaporate LC in a laboratory-scale evaporator to obtain purified condensate used for supplying water for circulating cooling water system. The influence of pH, hot air temperature and evaporation rate on COD and NH3–N in condensate were investigated to identify the optimum operation of this technology. The results showed that COD concentration in condensate obviously decreased with increase in hot air temperature. Higher hot air temperature led to higher initial evaporation temperature, and evaporation rate of water was significantly greater than that of small molecular organic matter with lower boiling point than water with increasing hot air temperature. Reduction in contents of phenol, ketone and benzene was responsible for COD decreasing in condensate. COD in condensate decreased with increase in pH, as the amount of volatile organic matter such as fatty acids escaped from LC to condensate decreased. The pH had little influence on the DOM in condensate according to EEM spectra analysis. Evaporation rate had little influence on COD in the condensate water. NH3–N concentrations in condensate in all experimental groups were far away from the limit value (10 mg/L) in the water quality standard. Under the premise of meeting water quality standard, the lowest temperature (450 °C) of hot air was selected to save energy and use lower grade waste heat. Therefore, the optimum condition was 450 °C of hot air, pH = 7 of LC and CF = 10. At this condition, molecular weight of DOM in the condensate was smaller and humification degree and aromaticity of DOM were lower according to UV–visible absorption spectrum analysis.

Understanding the patterns and health impact of indoor air pollutant exposures in Bradford, UK: a study protocol

IntroductionRelative to outdoor air pollution, there is little evidence examining the composition and concentrations of indoor air pollution and its associated health impacts. The INGENIOUS project aims to provide the...