Pyrolysis is an important thermochemical conversion process for biomass and is conducted in the absence of oxygen at temperatures between 400 and 1000 ∘C. Biomass pyrolysis yields cleaner combustion fuels by decreasing fuel-bound oxygen and nitrogen species, thus reducing NOX formation and net CO2 emissions. A structural model compound for cyclic peptides — important nitrogen-containing components in biomass — is 2,5-diketopiperazine (DKP). In this work, we apply an automated workflow that combines reactive molecular dynamics simulations with electronic structure calculations at different levels of theory to develop a detailed kinetic model for the pyrolysis of DKP at the level of elementary reaction steps. This complements previous studies that focused only on the net reaction scheme. The developed DKP kinetic submodel for pyrolysis is implemented in the kinetic modeling software OpenSMOKE++ . Under pyrolysis, DKP decomposes into hydrogen cyanide (HCN), carbon monoxide (CO) and hydrogen (H2). Ammonia (NH3) is not formed in primary decomposition steps but rather in secondary reactions involving the primary intermediates. The submodel qualitatively reproduces DKP pyrolysis products observed in a fluidized bed reactor under kinetically controlled conditions and provides a reliable basis for further studies on peptide decomposition. Beyond the specific kinetic submodel, this work proposes a general workflow for investigating thermal decomposition and combustion processes.

To evaluate the recent literature on differential exposure to and health risks from wildfire smoke across subpopulations, whether wildfire-derived PM2.5 affects health differently from non-wildfire-derived PM2.5, and how wildfire smoke composition affects health. We found inconsistent evidence of differential exposure to and health risks from wildfire PM2.5 by population subgroups. This could be due to variation in wildfire PM2.5 infiltration into buildings and ability to take individual protective actions, both of which have been noted to be related to socio-economic status in the recent scientific literature. Respiratory health endpoints have been the most consistent and commonly evaluated health outcome in studies of wildfire smoke; additional research is needed to resolve conflicting findings for non-respiratory health outcomes (e.g., cardiovascular disease). Although some recent studies have documented larger health risks from wildfire-derived as compared to non-wildfire-derived PM2.5, we document how further research could evaluate whether these findings are confounded by type of fuel burned, due to methodological concerns, or are true. We also conclude that more research is necessary to elucidate potential differences in health risks of constituents of wildfire smoke other than PM2.5 or from burning of different fuels. Wildfire smoke is projected to continue to increase. We encourage future research to move away from further documentation of respiratory health impacts of wildfire smoke, which has been very well established, into studies of other health endpoints that have been less well studied to date, more exploration into health effects from wildfire smoke constituents other than PM2.5 and from different types of fires (i.e., wildland urban interface (WUI) fires versus wildland fires), and additional exploration of remaining uncertainties with a goal of further supporting public health protection from wildfire smoke.

Potentially toxic elements (PTEs) pollution in the air and its sources and risks have become a major environmental problem faced by developing countries, especially plateau cities. This study determined the concentrations of seven PTEs in PM2.5 by Inductively Coupled Plasma Mass Spectrometry (ICP-MS), and comprehensively utilized methods such as geoaccumulation index (Igeo), enrichment factor (EF), principal component analysis (PCA), potential ecological risk index and health risk assessment to systematically analyze their pollution levels, sources and environmental risks. The results indicated that Cd pollution was the most severe (Igeo = 6.80 ± 0.49), while Tl pollution was the least (Igeo = 1.60 ± 0.53). The EF values of Cd and Ni are greater than 10, and the EF value of Cd even exceeds 100, indicating strong anthropogenic interference. PCA analysis indicates that traffic emissions, agricultural activities, industrial production, corrosion of building materials and combustion of fossil fuels are the main sources. The potential ecological risk assessment indicates that Cd has an extremely high single-element ecological risk (Ei = 5320.80 ± 1886.59). All non-carcinogenic health risks fall within the acceptable safety range (HQ < 1). However, the carcinogenic risk assessment reveals that Cr (Ⅵ) and As pose significant carcinogenic risks, and Ni exposure in adults should not be overlooked. This study provides multi-angle scientific evidence for PTE pollution in PM2.5 in plateau cities, emphasizing the need to take targeted intervention measures to reduce the risk of PTE exposure.

Nitrogen dioxide (NO2) is mainly discharged from the burning of fossil fuels and remains suspended in the air with other particulate pollutants, which has a significant impact on the Earth’s ecological environment and is harmful to human health. Schizophrenia is a nervous system disease involving emotion, thinking, and behavior. There is no consistent conclusion about the etiology of schizophrenia, though numerous studies are ongoing. Previous studies suggest that exposure to NO2 air pollution may increase the risk of schizophrenia, though this remains in the early exploratory stages. We conducted a 2-sample Mendelian Randomization study to investigate the potential causal effect of NO2 exposure on schizophrenia risk. Genetic instruments were selected from large-scale genome-wide association studies of European ancestry, including NO2 exposure (n = 456,380) and schizophrenia (n = 640,808). To ensure the reliability of our findings, we also conducted sensitivity analyses. Across all Mendelian Randomization models, NO2 exposure showed a significant positive causal effect on schizophrenia risk. Beta values ranged from 0.246 (weighted median estimator model, 102 single nucleotide polymorphisms) to 0.478 (inverse variance weighting model, 128 single nucleotide polymorphisms), with all P < .05. odds ratios ranged from 1.30 (95% confidence interval: 1.03–1.65, weighted median estimator, exposure: ukb-b-9942; outcome: ieu-b-5099) to 1.60 (95% confidence interval: 1.39–1.87, inverse variance weighting fixed effects, exposure: ukb-b-5620; outcome: ieu-b-5099). Sensitivity analyses and heterogeneity tests confirmed the robustness of these findings. These findings help further our understanding of the etiology of schizophrenia and provide a new perspective for air pollution mitigation.

Explainable AI-based optimization of facility operations for excessive NOx emission control: A case study of a solid refuse fuel combustion facility

Tailored in situ CuO coatings for enhanced ignition and combustion of boron-based fuels

External and internal exposure to PM2.5-bound PAHs from household solid fuel combustion: health effects mediated by urinary metabolites.

This study focuses on the search and determination of organic pollutants in aerosol particles (PM2.5) collected in Arkhangelsk, the largest urban agglomeration in the Arctic, during winter and summer periods. Thermal desorption gas chromatography coupled with high-resolution mass spectrometry was applied for non-targeted screening of atmospheric aerosols, enabling the detection of compounds at low concentrations ranging from 10 pg/m3 to several ng/m3. Representatives of various chemical classes were detected in samples from both seasons, including CHO compounds (with phthalates as the predominant subgroup), nitrogen-containing compounds (e.g., pyridines, quinolines, nicotine), phenols and monoaromatics, as well as polycyclic aromatic hydrocarbons and their oxygenated derivatives. In winter, PAHs and oxy-PAHs significantly predominated, likely due to increased combustion of fossil fuels and biomass for heating purposes. A total of approximately 300 compounds were identified via non-targeted screening, of which 32 were confirmed and quantified using authentic reference standards across six chemical classes. Seasonal variations in both the composition and concentration levels highlight the impact of local emission sources and atmospheric conditions on the organic aerosol profile in this arctic urban environment.

Toxicological impact of polycyclic aromatic hydrocarbons on uterine health and molecular insights via docking: A review.

Flue gas recirculation threshold: A novel promising concept for NOX control in quasi-mild combustion of syngas fuels.

Application of digital twin technology for combustion and emissions of sustainable aviation fuels

This study focused on the concentration of carbon oxides (CO and CO₂) and temperature in Iraq, using satellite remote sensing data from 2003 to 2024. It showed hot and cold spots in different locations in Iraq, and these spots are the result of the standard deviation of both carbon dioxide and temperature, showing the strong and weak correlation. The analysis of CO revealed spatial variations, with a strong correlation coefficient of approximately 0.63 in Basra and a significance level of 0.01. In Baghdad, the correlation reached 0.73, but not at a significant level, despite the standard deviation of CO being approximately 3.787. This CO is a product of fuel combustion, transportation, and other activities. Conversely, there was a weak, positive correlation between temperature and carbon dioxide. Hot spots emerged in Maysan Wasit, showing strong positive and positive correlations between temperature and carbon dioxide, with correlation coefficients of 1.208 and 1.134, respectively. Cool spots were also found in the north, exhibiting a moderate to weak positive correlation between temperature and carbon dioxide, resulting in negative deviations for both carbon oxides and temperature. This is attributed to the vegetation cover characteristic of the northern regions. This indicates that, over time, without alternative energy sources such as renewables, carbon oxides will have a significant impact on future temperatures in Iraq due to human activity and the burning of fuels, oil and gases.

ABSTRACT Over the past few decades, wildland fires have increased in frequency and severity across many regions of the world, particularly in the western United States. Smoldering combustion of solid fuels, a heterogeneous combustion mode that is particularly difficult to detect and suppress, plays an important role in fire persistence, emission generation, and the potential transition to flaming under favorable conditions. In this study, a wind tunnel setup was developed capable of investigating combustion behavior and emissions of different fuels found in wildland and urban areas under well-defined boundary conditions. Douglas fir lumber, a common softwood species found in the wildland and used in home structures in the US, was examined using three fuel sizes corresponding to volume-to-surface area ratios (V/SA) of 3.8 mm, 4.2 mm, and 5.4 mm, under constant heat power inputs of 100 W and 200 W and wind speeds ranging from 0.5 m/s to 1.5 m/s. Ignition was performed using a nichrome wire system from the bottom of the samples, while the exposed surfaces were subjected to a controlled crossflow of air. The mass loss rate of the fuels undergoing combustion was tracked using a precision mass balance, along with measurements of aerosol and major gaseous combustion product species. The experiments produced a combustion regime map, showing that fuel size and ignition power strongly influenced burning rates and observed combustion behavior. Larger V/SAs led to stronger burning rates and a greater propensity for the observed smoldering-to-flaming (StF) transition, accompanied by lower particulate matter emissions. Gaseous product emissions and modified combustion efficiency demonstrated correlations between carbon monoxide and carbon dioxide fractions and combustion behavior. The experimental data were compared with simplified theoretical analyses and found to be in reasonable agreement. This work enhances the understanding of the smoldering combustion behavior of a common solid fuel relevant to wildland and structural fire scenarios, providing experimental data obtained under well-defined boundary conditions, useful for emission characterization and model development.

Abstract. Major metropolitan areas are critical carbon emission hotspots, and understanding their carbon dynamics is essential for developing targeted climate mitigation strategies. Remote background stations often capture spatially smoothed anthropogenic signals, failing to resolve distinct urban source–sink processes. Here, we leveraged the unique 632 m Shanghai Tower (121.51° E, 31.23° N) to conduct a nearly 2-year field campaign (April 2021–March 2023), aiming to investigate CO2 and CO dynamic from the top of urban canopy layer (UCL) via stationary, continuous, single-level, high-precision, in situ measurements with a cavity ringdown laser spectrometer. Campaign-averaged mole fractions substantially exceeded global and regional backgrounds, confirming a pronounced urban carbon burden. Through a multi-stage filtering framework targeting nocturnal measurements, we derived robust regional background values. Component analysis of CO2 excess, using CO as a reliable regional combustion tracer, revealed burning of fossil fuels as the dominant contributor (avg. 85 %), alongside biogenic processes that enhanced this atmospheric excess, especially in winter under respiratory predominance, but less so in summer when partially offset by net photosynthetic uptake and cleaner airmass dilution. The 2022 Shanghai lockdown provided a natural experiment that underscored the pronounced sensitivity of UCL-top observations to metropolitan-scale anthropogenic perturbations, as reflected in synchronized decline and rapid rebound of CO2 and CO, along with a marked reversal of their emission ratio compared to 2021. Overall, these findings affirm that UCL-top observations effectively capture integrated metropolitan carbon signals, supporting refined emission tracking and top-down carbon neutrality strategies.

Atmospheric particulate matter poses a high risk by carrying potentially toxic components such as polycyclic aromatic hydrocarbons (PAHs). The major sources of these potentially toxic compounds include traffic-related emissions and winter heating, implying the combustion of fossil fuels or biomass. Air pollution, especially chronic exposure, poses the most serious human health hazard in childhood, and several studies emphasise the importance of research on the potential impacts of air pollution in school environments. While indoor air quality studies are already available in Hungary, investigations on outdoor air pollution in school environments are missing. To fill this gap, in a medium-sized Hungarian town, Veszprém, six schools were selected to assess air quality in the outdoor environments where schoolchildren spend their breaks and have physical training. These schools represent different locations and conditions, from high-trafficked sites to suburban environments. Using resuspended dust samples, environmental quality was assessed based on PAH contents of the samples and ecotoxicity tests (Vibrio fischeri bacterial bioassay). Ecotoxicity of the samples moved in a wide range, from highly toxic to non-toxic. PAH measurements indicated considerable contamination in the case of one sample taken from a suburban area. Source apportionment demonstrated that winter heating is also an important pollution source.

Ulaanbaatar, Mongolia, is in the midst of a winter air pollution crisis driven by the combustion of solid fuels in the peri-urban Ger districts to which young children, fetuses and pregnant women are particularly vulnerable. To address this, the Mongolian government banned the sale and use of raw coal in May 2019 and has subsidized and promoted refined coal briquettes as an alternative fuel. This mixed-methods study utilized semi-structured interviews (n = 30) and a questionnaire survey (n = 369) to identify facilitators and barriers to compliance with the ban amongst Mongolian mothers living in Ulaanbaatar. Four main themes were identified that affected compliance: knowledge about air pollution, information sources, initial policy impacts and governance. Facilitators of participants’ ban compliance included awareness of the severity of air pollution’s health impacts, support for the policy and governmental enforcement. Concerns regarding fuel alternative safety and affordability, as well as uncertainty about the policy itself (inadequate information) were found to be barriers. Incorporation of these insights in future air pollution mitigation strategies could be beneficial for strengthening their effectiveness, both in Mongolia and settings that face similar challenges throughout the world, which in turn could be a crucial step in meeting the 2030 Sustainable Development Goals agenda.

Investigation on the emission characteristics of NO and SO2 in the sewage sludge char co-combustion with biomass.

The world's cumulative photovoltaic (PV) installation surpassed 2 terawatt (TWp) in 2024, with annual installation expected to reach 1 TWp by 2030. As the industry reaches grid parity worldwide and becomes one of the main energy sources, we explore how the PV supply chain and industry could be decarbonised to maximise climate benefits and ensure its role as an even lower‐carbon energy source. Despite a significantly lower carbon footprint than coal electricity, there remains significant potential to further reduce PV emissions by over 80%. For example, 38% of it originated from electricity consumption – the combustion of fossil fuels in electricity generation. In this work, we expand upon a previous publication and propose a stepwise approach to reach significantly low electricity emissions below 1 gCO 2 ‐eq/kWh. This is accomplished by reducing embodied emissions in PV modules through the use of low‐emissions electricity, recycled and/or green materials and by reducing effective emissions over the module lifetime by increasing the electricity generation using high‐yield mounting structures at high‐insolation locations, improving module stability and enhancing module efficiency. Finally, we consider the impact of using this low‐emissions electricity from PV to power the manufacturing of PV modules, aiming to reach &lt;1 gCO 2 ‐eq/kWh.

Bioethanol fireplaces are marketed as clean and decorative heating alternatives. However, their impact on indoor air quality (IAQ) remains poorly characterised. This study investigates the indoor levels of gaseous and particulate pollutants using a bioethanol fireplace operated under realistic conditions. Two types of bioethanol fuels and two burner designs, a single-chambered (SC) and a double-chambered (DC), were tested under minimal ventilation. Concentrations of CO, NO, NO2, CO2, NH3, N2O, C2H6O, total volatile organic compounds (TVOCs), and carbonyl compounds were measured, while particulate matter (PM10) was characterised chemically and toxicologically. Combustion of both fuels led to substantial increases in indoor pollutant concentrations compared to background levels. Indoors, maximum average CO levels reached 5.67 µgm-3, NO 0.33 µgm-3, NO2 0.85 µgm-3 and TVOCs exceeded 1400 µg m-3. Acetaldehyde and formaldehyde were the dominant carbonyls, with the latter frequently surpassing the WHO guideline value along with NO2. Compared with traditional wood combustion, bioethanol combustion produced relatively higher indoor concentrations of nitrogen oxides, acetaldehyde, and formaldehyde. Average PM10 concentrations ranged from 31.5 to 173 µg m-3, with higher indoor concentrations for the DC burner and Fuel 2. PM10 samples were enriched in bromine, ammonium and nitrate during combustion, and exhibited elevated oxidative potential. Differences in indoor pollutant levels and oxidative potential were observed depending on the burner design, fuel type and initial fuel load. These results demonstrate that flueless bioethanol fireplaces can markedly deteriorate IAQ, underscoring the need for performance standards, improved fuel formulations, and adequate ventilation to mitigate exposure risks associated with their use.

Effects of methanol on the combustion and emission performance of ammonia-diesel fuels in a two-stroke low speed marine engine