Organic Emissions Research Articles

Full-Volatility Reactive Organic Carbon Emissions from Volatile Chemical Products in Mainland China

Full-Volatility Reactive Organic Carbon Emissions from Volatile Chemical Products in Mainland China

Rational design and synthesis of pyrrolo-pyridine dinitrile dyes with strong dual-state emission

In recent years, there has been a growing focus on organic dual-state emission (DSE) materials that demonstrate robust luminescence in both solid and solution states. Nevertheless, in the solid state, π-π stacking between organic molecules often results in pronounced luminescence quenching, posing a significant challenge for the design and synthesis of organic DSE materials. In this work, a pyrrolo-pyridine dinitrile (PPDN) dye was synthesized from commercially available 2-heteroaryl acetonitriles and classical diketopyrrolopyrrole (DPP) dye via a two-step process. Due to its special "J"-shaped planar conjugate structure, the PPDN dye has strong DSE performance, high molar extinction coefficients (ε), large Stokes shifts, and excellent optical and thermal stability. It also has aniline vision detection capability, which is useful in the field of security displays and anti-counterfeiting.

Full-Volatility Organic Emission and Oxidation: Key to the Puzzle of Atmospheric Reactive Organic Carbon

Full-Volatility Organic Emission and Oxidation: Key to the Puzzle of Atmospheric Reactive Organic Carbon

The conversion of biomass to biochar decreases soil organic and inorganic carbon-derived CO2 emissions under different water conditions in karst regions

Due to the unique geological background and climatic condition, karst soils in southwest China are mainly developed on carbonate rocks and accompanied by frequent dry-wet alternations. Therefore, the effects of biomass (BS) and biochar (BC) on the soil carbon pools (especially inorganic carbon) in karst regions are different from those in non-karst regions. In order to understand the responses of soil organic carbon (SOC) and soil inorganic carbon (SIC)-derived CO2 emissions to BS and BC amendments under different water conditions in karst regions, a microscopic study under dry-wet alternate (DW) and constant moisture (CM) conditions was established to investigate the stability of BC, BS, and their effects on SOC and SIC pools by isotope double-labeling methods. Results showed that the contribution rates of SOC and SIC to soil CO2 emissions were 51.55 %–99.52 %, 0.48 %–48.45 % and 60.55 %–97.72 %, 2.28 %–39.45 % under DW and CM conditions, respectively. Compared with the control, BS application under different water conditions increased SOC and SIC-derived CO2 emissions by 929.78˗1443.39 % and 169.69˗335.71 %, respectively. However, BC amendment significantly decreased SOC and SIC-derived CO2 emissions, especially in the DW condition. The mean residence time (the inverse of the decomposition rate) of BC in karst soils under different conditions ranged from 657 to 3105 years, which was much higher than those of BS (7˗18 years). Therefore, the conversion of BS to BC in karst regions enhances carbon sequestration due to its stability of recalcitrant carbon, the decrease of SOC and SIC- derived CO2 emissions. This study is helpful to understand the quantification of CO2 sources from calcareous soils and elucidate the environmental behaviors and carbon sequestration potentials of BC or BS amendments in karst regions.

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

Purpose Building 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/approach This 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. Findings The 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 implications The 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/value The 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.

Depletion of iodide in ageing aerosols and the role of humidity: A case study of mixed sodium iodide-malonic acid aerosol

Global sea to air iodine emissions, along with organic emissions and their oxidation products, have increased tremendously. This work presents a comprehensive analysis of the humidity mediated changes in ageing aerosols comprising iodide and water soluble dicarboxylic acid using aerosol micro-Raman spectroscopy. The studies in the model system, sodium iodide-malonic acid mixed aerosols, unveiled the depletion in iodide. Mechanistic insights gleaned through comparative studies conducted under inert (nitrogen) and oxidative (air) atmospheres reveal the iodide depletion occurs possibly via oxidation to molecular iodine. The reaction involves gaseous components, diffusion of which across the particles will be impacted by the physical state of the particles, such as viscosity, which in turn is intricately linked to ambient humidity levels. To this end, studies on the temporal evolution of the reaction at three distinct RHs covering 30–80% revealed the enhanced progression of the reaction with increasing humidity. Given that geographical locations serving as major sources for atmospheric iodine typically experience high humidity, these reactions could emerge as an additional process controlling iodine speciation in ageing aerosols.

Design of Oil Mist and Volatile-Organic-Compound Treatment Equipment in the Manufacturing Plant

To effectively confront the acute challenge of global warming, at the present stage, the Chinese government has designated carbon reduction as the core objective to accomplish the coordinated control of greenhouse gas and pollutant emissions. As China is a major manufacturing country, with the continuous improvement of air emission standards, it is particularly necessary to carry out the design of more efficient volatile organic pollutant emission devices. This study takes a treatment system with a waste gas ventilation volume of 6 × 104 m3·h−1 as an example, adopts the end treatment approach of adsorption and catalytic combustion coupling, and designs a purification device composed of multistage oil-mist recovery, electrostatic adsorption, dry filtration, activated-carbon adsorption and desorption, catalytic combustion, etc. It also employs the fuzzy proportional-integral-derivative fine temperature control algorithm, and the temperature overshoot was decreased by 85%. The average emission concentration of volatile organic compounds at the equipment outlet is 6.56 mg·m−3, and the average removal rate is 93.99%, far surpassing the national emission standards. The device operates efficiently and stably, confirming that the end-coupled treatment system based on the adaptive fuzzy proportional-integral-derivative temperature control strategy can effectively handle volatile organic compounds with oil mist and holds significant promotion and research value.

Modelling of atmospheric concentrations of fungal spores: a 2-year simulation over France using CHIMERE

Abstract. Fungal spore organic aerosol emissions have been recognised as a significant source of particulate matter as PM10; however, they are not widely considered in current air quality models. In this work, we have implemented the parameterisation of fungal spore organic aerosol (OA) emissions introduced by Heald and Spracklen (2009) (H&S) and further modified by Hoose et al. (2010) in the CHIMERE regional chemistry-transport model. This simple parameterisation is based on two variables, leaf area index (LAI) and specific humidity. We have validated the geographical and temporal representativeness of this parameterisation on a large scale by using yearly polyol observations and primary biogenic organic aerosol factors from positive matrix factorisation (PMF) analysis at 11 French measurement sites. For a group of sites in northern and eastern France, the seasonal variation of fungal spore emissions, displaying large summer and small winter values, is correctly depicted. However, the H&S parameterisation fails to capture fungal spore concentrations for a smaller group of Mediterranean sites with less data availability in terms of both absolute values and seasonal variability, leading to strong negative biases, especially during the autumn and winter seasons. Two years of CHIMERE simulations with the H&S parameterisation have shown a significant contribution of fungal spore OA to PM10 mass, which is lower than 10 % during winter and reaches up to 20 % during summer in high-emission zones, especially over large forested areas. In terms of contributions to organic matter (OM) concentrations, the simulated fungal spore contribution in autumn is as high as 40 % and reaches at most 30 % of the OM for the other seasons. As a conclusion, the fungal spore OA contribution to the total OM concentrations is shown to be substantial enough to be considered a major PM10 fraction and should then be included in state-of-the-art chemistry-transport models.

Double-Stage Anaerobic Digestion for Biohydrogen Production: A Strategy for Organic Waste Diversion and Emission Reduction in a South African Municipality

Landfilling of organic waste poses a significant environmental threat, heavily contributing to climate change. The diversion of waste is imperative, but pathways to implementing alternative waste management strategies are needed. Double-stage anaerobic digestion has been identified as a potential technique that can reduce greenhouse gas emissions and diminish the amount of waste landfilled. Still, further research is needed before its implementation at the municipal level. This paper explored the potential insertion of double-stage anaerobic digestion into the portfolio of alternative treatment methods using the case study of the eThekwini Municipality in Durban, South Africa, by proposing a source-separation waste management scheme and forecasting the organic waste generation for a 24-year timeframe until 2050. The WROSE model has been identified as the ideal tool for the analysis. A new scenario, including double-stage anaerobic digestion, has been introduced in WROSE after developing a country-specific emission factor. The technology has been assessed against similar techniques, namely anaerobic digestion and composting, according to the environmental indicators included in WROSE. Compared with the business-as-usual scenario and three other alternatives, the new scenario proved to be the second-most effective (−282% versus business-as-usual) after anaerobic digestion (−291%) in reducing climate-altering emissions, achieving analogous waste diversion rate (10.09%), landfill airspace (1,653,705 m3), and monetary savings (3.8 billion Rand) compared to composting and anaerobic digestion.

Substantial contribution of transported emissions to organic aerosol in Beijing

Haze in Beijing is linked to atmospherically formed secondary organic aerosol, which has been shown to be particularly harmful to human health. However, the sources and formation pathways of these secondary aerosols remain largely unknown, hindering effective pollution mitigation. Here we have quantified the sources of organic aerosol via direct near-molecular observations in central Beijing. In winter, organic aerosol pollution arises mainly from fresh solid-fuel emissions and secondary organic aerosols originating from both solid-fuel combustion and aqueous processes, probably involving multiphase chemistry with aromatic compounds. The most severe haze is linked to secondary organic aerosols originating from solid-fuel combustion, transported from the Beijing–Tianjing–Hebei Plain and rural mountainous areas west of Beijing. In summer, the increased fraction of secondary organic aerosol is dominated by aromatic emissions from the Xi’an–Shanghai–Beijing region, while the contribution of biogenic emissions remains relatively small. Overall, we identify the main sources of secondary organic aerosol affecting Beijing, which clearly extend beyond the local emissions in Beijing. Our results suggest that targeting key organic precursor emission sectors regionally may be needed to effectively mitigate organic aerosol pollution.

Near-Infrared II Fluorescence Imaging and Image-Guided siRNA Therapy of Atherosclerosis.

Targeting Ca2+/calmodulin-dependent protein kinase γ (CaMKIIγ) in macrophages using RNAi nanotechnology represents an innovative and promising strategy in the diagnosis and treatment of atherosclerosis. Nevertheless, it remains elusive because of the current challenges associated with the systemic delivery of siRNA nanoparticle (NP) to atheromatous plaques and the complexity of atherosclerotic plaques. Here, we demonstrate the potential of a thienothiadiazole-based near-infrared-II (NIR-II) organic aggregation-induced emission (AIE) platform encapsulated with the Camk2g siRNA to effectively target CaMKIIγ in macrophages for dynamic imaging and image-guided gene therapy of atherosclerosis. The nanoparticles effectively decreased CaMKIIγ expression and increased the expression of the efferocytosis receptor MerTK in plaque macrophages, leading to a reduction in the necrotic core area of the lesion in an aortic plaque model. Our theranostic approach highlights the substantial promise of near-infrared II (NIR-II) AIEgens for imaging and image-guided therapy of atherosclerosis.

Long-term escape behavior and release mechanism of organic emissions from asphalt materials

In the context of carbon neutrality and carbon peaking, investigating the long-term escape behavior and release mechanism of organic emissions from asphalt materials can contribute to the development of environmentally sustainable asphalt pavements. In this study, the long-term emission behavior and release mechanism of organic emissions from asphalt materials were unraveled by combining the headspace gas chromatography–mass spectrometry (HS-GC–MS), differential scanning calorimetry (DSC), fluorescence microscopy (FM), and Fourier transform infrared spectroscopy (FTIR) tests. The results demonstrate that the pressure aging vessel (PAV) test and the ultraviolet (UV) aging test can result in a notable reduction in the concentration of organic emissions from asphalt materials, respectively. This indicates that asphalt pavements can potentially release a substantial quantity of organic emissions during their long-term service life. Besides, the aging mechanism of asphalt materials is established to unravel the release mechanism of organic emissions from asphalt materials. Aging increases the probability of organic emissions being released and volatilized from asphalt materials, which leads to the organic emissions from asphalt materials being more likely to be released and volatilized. Consequently, the aging process facilitates a greater release and volatilization of organic emissions from asphalt materials, resulting in a decrease in the detected concentration of these emissions after aging.

Long-term Trends of Dissolved Organic Carbon Dynamics in a Subtropical Forest Responding to Environmental Changes.

Dissolved organic carbon (DOC) dynamics are critical to carbon cycling in forest ecosystems and sensitive to global change. Our study, spanning from 2001 to 2020 in a headwater catchment in subtropical China, analyzed DOC and water chemistry of throughfall, litter leachate, soil waters at various depths, and streamwater. We focused on DOC transport through hydrological pathways and assessed the long-term trends in DOC dynamics amidst environmental and climatic changes. Our results showed that the annual DOC deposition via throughfall and stream outflow was 14.2 ± 2.2 and 1.87 ± 0.83 g C m-2 year-1, respectively. Notably, there was a long-term declining trend in DOC deposition via throughfall (-0.195 mg C L-1 year-1), attributed to reduced organic carbon emissions from clean air actions. Conversely, DOC concentrations in soil waters and stream waters showed increasing trends, primarily due to mitigated acid deposition. Moreover, elevated temperature and precipitation could partly explain the long-term rise in DOC leaching. These trends in DOC dynamics have significant implications for the stability of carbon sink in terrestrial, aquatic, and even oceanic ecosystems at regional scales.

ToF-SIMS evaluation of PEG-related mass peaks and applications in PEG detection in cosmetic products

Polyethylene glycols (PEGs) are used in industrial, medical, health care, and personal care applications. The cycling and disposal of synthetic polymers like PEGs pose significant environmental concerns. Detecting and monitoring PEGs in the real world calls for immediate attention. This study unveils the efficacy of time-of-flight secondary ion mass spectrometry (ToF-SIMS) as a reliable approach for precise analysis and identification of reference PEGs and PEGs used in cosmetic products. By comparing SIMS spectra, we show remarkable sensitivity in pinpointing distinctive ion peaks inherent to various PEG compounds. Moreover, the employment of principal component analysis effectively discriminates compositions among different samples. Notably, the application of SIMS two-dimensional image analysis visually portrays the spatial distribution of various PEGs as reference materials. The same is observed in authentic cosmetic products. The application of ToF-SIMS underscores its potential in distinguishing PEGs within intricate environmental context. ToF-SIMS provides an effective solution to studying emerging environmental challenges, offering straightforward sample preparation and superior detection of synthetic organics in mass spectral analysis. These features show that SIMS can serve as a promising alternative for evaluation and assessment of PEGs in terms of the source, emission, and transport of anthropogenic organics.

Machine learning assisted designing of conjugated organic chromophores, light absorption, and emission behavior prediction

Organic materials have several important characteristics that make them suitable for use in optoelectronics and optical signal processing applications. For absorption and emission maxima, the stabilities and photoactivities of conjugated organic chromophores can be tailored by selecting a suitable parent structure and incorporating substituents that predictably change the optical characteristics. However, a high-throughput design of efficient conjugated organic chromophores without using trial-and-error experimental approaches is required. In this study, machine learning (ML) is used to design and test the conjugated organic chromophores and predict light absorption and emission behavior. Many machine learning models are tried to select the best models for the prediction of absorption and emission maxima. Extreme gradient boosting regressor has appeared as the best model for the prediction of absorption maxima. Random forest regressor stands out as the best model for the prediction of emission maxima. Breaking Retrosynthetically Interesting Chemical Substructures (BRICS) is used to generate 10,000 organic chromophores. Chemical similarity analysis is performed to obtain a deeper understanding of the characteristics and actions of compounds. Furthermore, clustering and heatmap approaches are utilized.

Enhancing optical biosensing: Comparing two physical treatments for GPTES chemical functionalization of Cyclo-Olefin Copolymer foil

Cyclo-olefin-copolymer (COC) transparent films are currently the best choice for micro-fluidic bio-sensors for point-of-care diagnostic applications using optical signal detection. However, while the optical and mechanical properties of this polymer are extremely good, the adhesion of the bio-probes on this surface is not optimal, due to its chemical structure, that presents only saturated carbon bonds. The deposition of organo-silane molecules on the COC surface is one of the most effective ways to overcome this problem. But, for the surface functionalization, a surface physical treatment is necessary before the chemical modification of the COC surface. In this paper a comparison of the effectiveness of two different physical treatments, oxygen plasma and UV-ozone, is reported. In particular, the exposure time of the UV-Ozone treatment has been selected to avoid the problem of auto-fluorescence of the modified COC surface, that was observed also for relatively short UV exposure (around 10 min). An investigation of the reactive radicals created on the surface after the physical treatments and the following chemical modification with the organo-silane molecule (GPTES) has been performed using X-ray photoemission spectroscopy. The surface energy and morphology of the films have been also measured by contact angle and optical profilometry. Finally, the bio-probes adhesion performances of the COC surfaces obtained with the two physical treatments and the chemical modification were tested in a fluorescence-based assay, using an organic light emission diode to excite the fluorescence. We observed that the UV-ozone treatment allows to obtain a siloxane network with some reactive epoxy radicals on the COC surface, however, their quantity and distribution are less important and homogeneous than in the oxygen plasma treated surfaces.

The organic acid environmental capacity of mangrove ecosystem in Dongzhai harbor, Hainan, China

To establish a method for studying the organic acid environmental capacity of mangrove ecosystems, high-performance liquid chromatography was used to measure the organic acid detoxification agent; Using different cultivation methods to determine the toxicity threshold of organic acids on mangrove plants; Calculate the environmental capacity of organic acids by combining the toxicity threshold of organic acids with the volume of water in the study area. The results showed the range of toxicity thresholds of organic acids to 25.29–30 mg/L would have an inhibitory effect on the development of mangrove plant hypocotyls; The organic acid environmental capacity of Dongzhai harbor Mangrove Wetland Protection Area is 7.76 × 10^4 kg/d ~ 8.73 × 10^4 kg/d, while the estimated organic acid emissions from shrimp ponds around Dongzhai harbor are 7.06 × 10^3 kg/d ~ 7.83 × 10^3 kg/d. Therefore, the organic acid emissions from shrimp ponds around Dongzhai harbor are within the carrying range of the mangrove wetland ecosystem in Dongzhai harbor.

Development of organic aggregation-induced emission fluorescent materials based on machine learning models and experimental validation

Organic fluorescent materials have attracted significant attention due to their unique chemical and optoelectronic properties. Unfortunately, traditional organic fluorescent materials are limited by aggregation-caused quenching (ACQ), which restricts their application potential in various fields. The discovery of aggregation-induced emission (AIE) materials has revolutionized the field by providing a solution to this issue. Despite considerable efforts to design and synthesize novel AIE materials, the development process still relies on tedious trial-and-error methods. Therefore, advanced cross-disciplinary techniques must be introduced to establish AIE property prediction models and enhance the development efficiency of organic AIE fluorescent materials. Machine learning (ML) is a powerful tool that has been widely applied across diverse fields to accelerate material development through complex relationship mapping of large data sets. This study presents an ML-based approach aimed at accelerating the development of organic AIE fluorescent materials. We assembled a dataset of 3,074 molecules with AIE/ACQ properties, developed a prediction model using the LightGBM ensemble learning algorithm, and used combined molecular fingerprints as input. The model achieved a remarkable independent test-set accuracy of up to 0.974 and its extrapolation ability was validated by out-of-sample validation (accuracy = 0.963). In addition, experimental validation was performed to assess the reliability of the ML prediction model in an unknown molecular space, showing a satisfactory agreement between the model predictions and the experimental results. Our work highlights the potential of ML for rapidly and accurately predicting the AIE property of unknown molecules and screening AIE materials, thereby accelerating the development of organic AIE fluorescent materials.

Compositional analysis and quantitative evaluation of organic emissions from asphalt materials: Improvements and refinements

The organic emissions resulting from the use and application of asphalt materials can pose significant risks to plant, animal life and human health, consequently, it is crucial to conduct compositional analysis and quantitative evaluation of organic emissions from asphalt materials. In this study, the qualitative and quantitative analysis method of organic emissions from asphalt materials was developed based on headspace gas chromatography-mass spectrometry (HS-GC-MS), selected ion monitoring (SIM) mode, internal standard method and calibration curve. The spiked recovery and surrogate standard recovery were employed to validate the method. The results show the excellent accuracy, precision, and reliability of the HS-GC-MS quantitative analysis method. And the results provide confirmation that total volatile organic compounds (TVOCs), polycyclic aromatic hydrocarbons (PAHs), and n-alkanes can indeed be identified as typical organic emissions originating from asphalt materials. Furthermore, the study successfully identifies benzothiazole, cyclohexyl disulfide, and N-(1,3-dimethylbutyl)-N′-phenyl-1,4-phenylenediamine as characteristic emissions in crumb rubber-modified asphalt (CRMA). The inclusion of the styrene-butadiene-styrene (SBS) modifier results in a significant reduction in n-alkane emissions by 41.11%, PAHs emissions by 25.22%, and TVOCs emissions by 47.21% in comparison to the base asphalt, demonstrating the effective inhibitory effect of the SBS modifier on organic emissions. When compared to the base asphalt, the addition of crumb rubber results in increased emissions of n-alkanes by 12.68% and PAHs by 50.60%, as well as the introduction of the emissions associated with CRMA characteristic compounds, indicating that the emission issue of CRMA is particularly prominent.

Organic Emissions of Volatile Chemical Products in Canada: Emission Inventories, Indoor-to-Outdoor Transfer, and Regional Impacts.

The contribution of volatile chemical products (VCPs) to ambient air pollution has increased following decades of regulating combustion sources. There is a research gap concerning the impact of indoor physicochemical phenomena on VCP emissions. In this work, a bottom-up speciated VCP emission inventory with indoor-outdoor resolution was developed for Canada, an industrialized country with low air pollution levels, whose major cities are among the largest urban areas in North America. VCPs were estimated to account for about 290 kilotons of gaseous organic emissions for a typical year in the 2010s, with more than 60% of emissions occurring indoors. Coatings and cleaners were the most emissive VCP categories. Oxygenated species and saturated aliphatics dominated the chemical profiles of most emissions. Less than 5% of VCP emissions were impacted by indoor physicochemical phenomena. VCP emissions were predicted to account for 0.8-3.2 s-1 of OH reactivity and 0.22-0.52 μg/m3 of secondary organic aerosol formation potential in major urban areas in Canada. Our predictions aligned with previous measurements concerning indoor and outdoor organic pollutant levels, underscoring the important air quality impacts of VCPs relative to other sources. Our results provide helpful insights for future research regarding VCP emissions, especially from indoor spaces.