Particulate Emissions Research Articles

Particulate Matter Production from Prescribed Burns in the Chicagoland Area

Prescribed burns are a land management tool currently used to aid in fire mitigation and to promote desired plant species and reduce undesired species, which are often invasive species. Currently, there is a public stigma surrounding the negative effects of prescribed burns, which impacts their use near residential areas. There are also particular challenges of conducting prescribed burns in urban and suburban areas. A better understanding of these relatively small-scale prescribed burns and their impact on atmospheric chemistry and air quality can allow for better communication with the public about their positive impacts, as well as for the acknowledgement and quantification of their drawbacks. This study considers the particulate matter concentrations proximate to prescribed fires being conducted in the greater Chicago metropolitan area. We deployed low-cost sensors in the spring and fall of 2022 at four sites. Concentrations of particulate matter exceeded accepted human health exposure limits at locations that burn crews would experience, but levels quickly returned to baseline after the high-intensity phase of the burn. With the ever-expanding wildland–urban interface and increased efforts in ecological restoration, understanding the particulate matter emissions of prescribed fires conducted near populated areas can provide more data regarding air quality impacts. These impacts should be weighed against the ecological benefits of prescribed burns and potential air quality impacts from uncontrolled burns from ecosystems that are not treated with prescribed burns. Measuring air quality impacts can also inform fire management practices with the goal of reducing future emissions. With the very present effects of climate change, understanding baselines regarding prescribed fires can better equip future research and fire professionals in fighting fire with fire.

Finding cost-effective options to reduce fine particulate matter emissions in a city highly polluted by firewood heaters

Finding cost-effective options to reduce fine particulate matter emissions in a city highly polluted by firewood heaters

Effect of Biofuel Use on Ship Engine

This research examines the effect of biofuel use on ship engine performance, with a focus on performance, efficiency and environmental impact. Experimental studies were conducted using four-stroke marine diesel engines operated with various blends of biofuels and conventional fuels. The measured parameters include engine power, specific fuel consumption, thermal efficiency, and exhaust emissions. The results showed that the use of biofuels at certain concentrations can produce performance comparable to conventional fuels, with some significant differences. Engine power decreased slightly (2-5%) at high biofuel blends, but thermal efficiency increased up to 3% at optimal blends. Specific fuel consumption increased by about 5-8% compared to conventional fuel. Exhaust emissions analysis showed a significant reduction in carbon monoxide (CO) and particulate emissions, with up to 30% and 40% reductions respectively. However, there was a slight increase in oxides of nitrogen (NOx) emissions by 5-10%. The study also identified several technical challenges in the use of biofuels, including the potential degradation of certain engine components and the need for fuel system modifications.

In silico estimation of polyethylene glycol coating effect on metallic NPs radio-sensitization in kilovoltage energy beams

PurposeNanoparticles (NPs) as radiosensitizers present a promising strategy for enhancing radiotherapy effectiveness, but their potential is significantly influenced by the properties of their surface coating, which can impact treatment outcomes. Most Monte Carlo studies have focused on metallic NPs without considering the impact of coating layers on radiosensitization. In this study, we aim to assess both the physical and radiobiological effects of nanoparticle coatings in nanoparticle-based radiation therapy.Materials and methodsIn this simulation study, we used Geant4 Monte Carlo (MC) toolkit (v10.07.p02) and simulated the bismuth, gold, iridium and gadolinium NPs coated with polyethylene glycol (PEG-400: Density: 1.13 g/cm³, Molar mass: 380–420 g/mol) as radiosensitizer for photon beams of 30, 60 and 100 keV. Secondary electron number and reactive oxygen species enhancement factor were estimated. Also, dose enhancement factor (DEF) was determined in spherical shells with logarithmic scale thickness from the nanoparticle surface to 4 mm.ResultsSecondary electron emission was highest at 30 keV for gold, bismuth, and iridium NPs, while gadolinium NPs peaked at 60 keV. Coating reduced electron emissions across all energies, with thicker coatings leading to a more significant decrease. DEF values declined with increasing radial distance from the NP surface and were lower with thicker coatings. For gadolinium NPs, DEF behavior differed due to K-edge energy effects. Reactive species generation varied, showing maximum production at 30 keV for gold, bismuth, and iridium NPs, while gadolinium NPs showed peak activity at 60 keV. PEG coatings enhanced reactive species formation at 100 keV.ConclusionThe findings indicate that the coating layer thickness and material not only influence the emission of secondary particles and DEF but also affect the generation of reactive species from water radiolysis. Specifically, thicker coatings reduce secondary particle emission and DEF, while PEG coatings demonstrate a dual behavior, offering both protective and enhancing effects depending on photon energy. These insights underscore the importance of optimizing NP design and coating in future studies to maximize therapeutic efficacy in nanoparticle-based radiation therapy.

Quantifying particulate matter emission rates from naturally ventilated dairy buildings by considering roof opening contributions

Roof openings are typically fitted to naturally ventilated dairy building (NVDB) for better ventilation but their impact on air pollutant emission calculations has not been fully considered. Particulate matter (PM) emission rate (ER) for NVDB rely on the total ventilation rate (VR), outdoor PM concentration and average indoor PM concentration sampled either under the roof (Roof Sampling) or in the cubicle area (Cubicle Sampling), which may show large deviations due to its spatiotemporal variation of PM concentrations and complex airflow patterns. This study utilised a novel ER calculation method (Joint Sampling) that computes the respective emission from the roof and sidewall openings by matching each outlet's VR and PM concentration. By year-round field measurements of PM2.5 and the total suspended particulates (TSP), results showed that annual average ERs of PM2.5 and TSP were 10.8 mg h−1 cow−1 and 45.7 mg h−1 cow−1 for Roof Sampling, 12.7 mg h−1 cow−1 and 40.7 mg h−1 cow−1 for Cubicle Sampling, and 11.7 mg h−1 cow−1 and 45.9 mg h−1 cow−1 for Joint Sampling. Considering the Joint Sampling results were relatively true, Roof Sampling exhibited a maximum underestimate of PM2.5 emissions of 20.8% when sidewall curtains were fully opened, whilst Cubicle Sampling demonstrated a maximum overestimate of TSP of 10.2% when the aperture was closed. Using Joint Sampling, the roof opening contributed 39.3% and 24.4% of the annual PM2.5 and TSP emissions. When sidewall openings are partially or fully closed, the Joint Sampling calculation is preferable to estimate the ER of PM.

Engaging Communities in Energy Transitions: A Study on Attitudes Towards Sustainable Heating Technologies and the Role of Peer Effects in Southern Chile

This study investigates the role of peer effects in shaping the adoption of sustainable heating systems in two highly polluted communes in Southern Chile. Despite policies promoting cleaner alternatives, wood-burning stoves, a major source of particulate matter emissions, remain widespread. This research work addresses a critical gap in the literature by examining how peer influence—typically studied in relation to visible technologies like solar panels or electric vehicles—affects the adoption of less visible but essential sustainable heating technologies. The main objective of this study is to understand how peer networks can influence the attitudes of residents towards sustainable heating technologies in highly polluted urban environments. Employing a non-experimental, cross-sectional design with a sample of 244 participants, this study reveals that peer effects and health risk perception are significant predictors of positive attitudes towards sustainable heating systems. These findings contribute valuable insights for policymakers seeking to accelerate energy transitions in polluted regions.

The emission and physicochemical properties of airborne microplastics and nanoplastics generated during the mechanical recycling of plastic via shredding

This study examined the emission and physicochemical properties of microplastics and nanoplastics (MPs/NPs) generated during shredding, which is regularly used in mechanical recycling. Waste and new polyethylene terephthalate, polypropylene, and high-density polyethylene were investigated herein for a total of six categories. The concentration and size distribution of particles were measured using two spectrometer instruments, and morphology and elemental composition of emitted particles were analyzed with microscopy and spectroscopy. This study found that number concentrations in both submicron and micron sizes of respirable particles were 3–2910× higher during periods of shredding than pre-shredding background concentrations. Maximum concentrations of particles within 10–420 nm, across all six categories, ranged from 22,000- to 1,300,000-particles/cm3 during shredding, compared to average background levels of 700 particles/cm3. Maximum concentrations of particles within 0.3 to 10 μm, across all six categories, ranged from 24- to 2000-particles/cm3 during shredding, compared to average background levels of 2 particles/cm3. Waste plastics consistently generated higher emissions than their new counterparts, which is attributed to the labels, adhesives, and increased additives incorporated into the waste plastic. Morphology varied drastically between particles and an elemental composition analysis found that the samples consisted primarily of C and O, representing the polymer material, as well as Na, Mg, Al, Si, Cu, Cl, K, Ca, Ti, Fe, Rb, and Br representing additives, label, and other contaminates. The shredding of plastic has the potential to expose workers to elevated concentrations of airborne MPs/NPs, especially those between 10 and 100 nm.

Innovativeness of the European economies in the context of the modified European Innovation Scoreboard

Research background: Innovation is an important determinant of economic development, and its importance is growing with the advancement of digitization and the development of the Fourth Industrial Revolution. In turn, the assessment of the innovativeness of a country’s economy affects its investment attractiveness and international image. Purpose of this study: Given the factors presented above, the main aim of this study is to explore and compare the innovativeness of European economies in the context of the modified European Innovation Scoreboard. Methods: To achieve this goal, the authors propose two key modifications of the existing innovation assessment methodology contained in the European Innovation Scoreboard. The first concerns the principles of the normalization of assessment indicators and aims to eliminate extreme assessment values. The second proposes to remove the indicators which are difficult to measure, subjective, and not always useful: (1) those related to sustainable development (resource productivity; emissions of fine particulates; and environment-related technologies) and (2) those that take into account only small and medium-sized enterprises (SMEs introducing product innovations; SMEs introducing business process innovations; and innovative SMEs collaborating with others). Findings & value added: An alternative approach to assessing the innovativeness of the analyzed countries — as proposed by the authors — resulted in changes in the ranking of countries in relation to the European Innovation Scoreboard, but the changes were not significant. The major changes concerned Serbia (down four places), Belgium (down two places), Hungary (up three places), and Poland (up two places). In addition, five countries moved up one place in the ranking (the UK, the Netherlands, Luxembourg, Estonia, Slovenia, Spain, and Slovakia), and five lost one place in the ranking (Norway, Italy, Portugal, Greece, and Croatia). Thirteen countries had no changes. The obtained results allowed us to conclude that the countries with the best and the worst innovativeness maintained the assessment level regardless of changes in the methodology of its implementation. The objectification of rules had the strongest impact on the countries in the middle of the ranking. This study draws attention to the problem of the subjectivity of the innovation rankings. It has also been documented that modifying the selection of evaluation criteria may change the final position in the ranking, which, in the case of emerging and developing economies, may affect investor assessment and economic growth opportunities. Such considerations are important because they are outside the often uncritical mainstream approach to the assessment of the innovativeness of economies. The conclusions imply the need for a multisource analysis of innovation and a critical look at the proposed methodologies.

Characterization of Lithium-Ion Battery Fire Emissions—Part 2: Particle Size Distributions and Emission Factors

The lithium-ion battery (LIB) thermal runaway (TR) emits a wide size range of particles with diverse chemical compositions. When inhaled, these particles can cause serious adverse health effects. This study measured the size distributions of particles with diameters less than 10 µm released throughout the TR-driven combustion of cylindrical lithium iron phosphate (LFP) and pouch-style lithium cobalt oxide (LCO) LIB cells. The chemical composition of fine particles (PM2.5) and some acidic gases were also characterized from filter samples. The emission factors of particle number and mass as well as chemical components were calculated. Particle number concentrations were dominated by those smaller than 500 nm with geometric number mean diameters below 130 nm. Mass concentrations were also dominated by smaller particles, with PM1 particles making up 81–95% of the measured PM10 mass. A significant amount of organic and elemental carbon, phosphate, and fluoride was released as PM2.5 constituents. The emission factor of gaseous hydrogen fluoride was 10–81 mg/Wh, posing the most immediate danger to human health. The tested LFP cells had higher emission factors of particles and HF than the LCO cells.

Evaluation of Current and Future Aviation Fuels at High-Pressure Rich-Quench-Lean-Type Combustor Conditions

Abstract Decarbonizing the aviation sector is one of the biggest challenges to minimize climate change effects associated with carbon dioxide emission. Sustainable aviation fuels will play a major role in this context especially for long-distance flights where hydrogen or all-electric propulsion systems do not present a feasible alternative. In addition, aromatic-free sustainable aviation fuels offer a promising solution to lower soot emissions of aeroengines. Jet A-1 as reference fuel, two blends, and two neat synthesized paraffinic kerosenes (SPKs) from hydroprocessed esters and fatty acids (HEFA) were tested to characterize the combustion behavior of drop-in/near drop-in fuels. Experiments in an optically accessible high-pressure rich-quench-lean (RQL)-type combustor at typical aeroengine conditions were performed using optical diagnostics, exhaust gas, and particle sampling measurements to delineate the fuel effects on spray, flame, and emission characteristics. Measurements were performed at pressures up to 10 bar, air preheating temperatures up to 773 K and primary zone equivalence ratios up to 1.66. Liquid fuel distribution and fuel placement were found to be sensitive to fuel properties. By contrast, no pronounced influence on flame position and shape were observed. As a consequence, NOx and CO emissions of the tested fuels differed only moderately. However, particulate matter measurements at the fuel richest operating condition showed a clear fuel ranking with the lowest particle emissions evident for the two neat HEFA-SPK samples. Moreover, the particle volume concentration at the fuel richest condition followed the expected trend with fuel H-content.

Molecular Insights into Gas-Particle Partitioning and Viscosity of Atmospheric Brown Carbon.

Biomass burning organic aerosol (BBOA), containing brown carbon chromophores, plays a critical role in atmospheric chemistry and climate forcing. However, the effects of evaporation on BBOA volatility and viscosity under different environmental conditions remain poorly understood. This study focuses on the molecular characterization of laboratory-generated BBOA proxies from wood pyrolysis emissions. The initial mixture, "pyrolysis oil (PO1)", was progressively evaporated to produce more concentrated mixtures (PO1.33, PO2, and PO3) with volume reduction factors of 1.33, 2, and 3, respectively. Chemical speciation and volatility were investigated using temperature-programmed desorption combined with direct analysis in real-time ionization and high-resolution mass spectrometry (TPD-DART-HRMS). This novel approach quantified saturation vapor pressures and enthalpies of individual species, enabling the construction of volatility basis set distributions and the quantification of gas-particle partitioning. Viscosity estimates, validated by poke-flow experiments, showed a significant increase with evaporation, slowing particle-phase diffusion and extending equilibration times. These findings suggest that highly viscous tar ball particles in aged biomass burning emissions form as semivolatile components evaporate. The study highlights the importance of evaporation processes in shaping BBOA properties, underscoring the need to incorporate these factors into atmospheric models for better predictions of BBOA aging and its environmental impact.

Creating respiratory pathogen-free environments in healthcare and nursing-care settings: a comprehensive review.

Hospital- and nursing-care-acquired infections are a growing problem worldwide, especially during epidemics, posing a significant threat to older adults in geriatric settings. Intense research during the COVID-19 pandemic highlighted the prominent role of aerosol transmission of pathogens. Aerosol particles can easily adsorb different airborne pathogens, carrying them for a long time. Understanding the dynamics of airborne pathogen transmission is essential for controlling the spread of many well-known pathogens, like the influenza virus, and emerging ones like SARS-CoV-2. Particles smaller than 50 to 100µm remain airborne and significantly contribute to pathogen transmission. This review explores the journey of pathogen-carrying particles from formation in the airways, through airborne travel, to deposition in the lungs. The physicochemical properties of emitted particles depend on health status and emission modes, such as breathing, speaking, singing, coughing, sneezing, playing wind instruments, and medical interventions. After emission, sedimentation and evaporation primarily determine particle fate. Lung deposition of inhaled aerosol particles can be studied through in vivo, in vitro, or in silico methods. We discuss several numerical lung models, such as the Human Respiratory Tract Model, the LUng Dose Evaluation Program software (LUDEP), the Stochastic Lung Model, and the Computational Fluid Dynamics (CFD) techniques, and real-time or post-evaluation methods for detecting and characterizing these particles. Various air purification methods, particularly filtration, are reviewed for their effectiveness in healthcare settings. In the discussion, we analyze how this knowledge can help create environments with reduced PM2.5 and pathogen levels, enhancing safety in healthcare and nursing-care settings. This is particularly crucial for protecting older adults, who are more vulnerable to infections due to weaker immune systems and the higher prevalence of chronic conditions. By implementing effective airborne pathogen control measures, we can significantly improve health outcomes in geriatric settings.

Reducing Particle Emissions from Marine Engines

Reducing Particle Emissions from Marine Engines

Comprehensive analysis of particle emissions from miniature turbojet engine

Emission of particulate matter from jet engines contribute to deterioration of air quality in the vicinty of the airports and to formation of contrails in higher layers of the atmosphere. This article presents the results of the measurements of particle emissions from a miniature jet engine GTM-120 fueled conventional aviation fuel Jet A-1. Analysis of particle size distribution, number, mass and volume emission indexes has been made, as well as the analysis of the emission intenisty and mass emission rate. Obtained results were related to LTO cycle phases. The results shows, that the particle number concentration was the lowest for low engine loads, with characteristic diameter of 69.8 nm and the particles concentration of 7.7 x 106 particles/cm3. For thrust increase, the characteristic diameter is smaller, and the particles distribution is no longer single-mode. The highest particles concentration for cm3 is for 100% thrust and is equal to 1.55 x 107 particles, with characteristic diameter of 34 nm.

Unveiling the mechanism secret of abrasion emissions of particulate matter and microplastics

Recent research highlights that non-exhaust emissions from the abrasion of tires and other organic materials have emerged as a substantial source of airborne particulate matter and marine microplastics. Despite their growing impact, the underlying mechanisms driving these abrasion emissions have remained largely unexplored. In this study, we uncover that abrasion emissions from organic materials are fundamentally governed by a fatigue fracture process, wherein particles are progressively detached from the material surface under cyclic abrasion loads. Our findings demonstrate that these emissions increase significantly only when the applied abrasion loads surpass the material’s toughness threshold. We establish a scaling relationship between the concentration of emitted particulate matter and the measurable crack propagation rate of the organic material, offering a robust quantitative method to estimate abrasion emissions. This work not only introduces a novel mechanistic framework for understanding particulate matter pollution from organic material abrasion but also provides a scientific basis for developing strategies to mitigate emissions of airborne particulates and marine microplastics.

Investigating Respiratory Disease Transmission Patterns Around the Figuil Cement Works

The objective of this research is to examine the dissemination of respiratory illnesses, exacerbated by the airborne pollutants emitted by the Figuil cement works, among the local population residing in the vicinity. The primary objective is to examine the impact of pollution, particularly the emission of fine particles and noxious gases, on the transmission of respiratory diseases such as asthma, chronic bronchitis and other lung disorders. The modified SEIR (Susceptible-Exposed-Infected-Recovered) epidemiological model is employed for the analysis of transmission dynamics within the community. This model incorporates environmental, health and demographic variables, thereby enabling the simulation of disease transmission as a function of varying pollution levels. Particular emphasis is placed on vulnerable groups, such as children and the elderly, due to immunosenescence, who are more likely to suffer from the adverse effects of pollution. The results will facilitate the formulation of efficacious strategies, including the implementation of awareness-raising campaigns and the introduction of sophisticated systems for the filtration and capture of pollutants at their source, such as fine particle filters or devices for the reduction of nitrogen oxides (NOx), with the objective of limiting the spread of respiratory diseases in at-risk areas and the formulation of suitable control measures.

Measurements of particle emissions of an A350-941 burning 100 % sustainable aviation fuels in cruise

Measurements of particle emissions of an A350-941 burning 100 % sustainable aviation fuels in cruise

Optimising the Particulate Emission Characteristics of a Dual-Fuel Spark Ignition Engine by Changing the Gasoline Direct Injection Strategy

In the current global scenario, it is essential to find more effective and practical solutions to mitigate the problem of particulate emissions from vehicles. In this research, particulate emission characteristics with changing GDI pressure or applying a split GDI strategy with different second injection timings were initially explored in a Dual-Fuel Spark Ignition (DFSI) engine, which employs Ethanol Port Injection (EPI) plus Gasoline Direct Injection (GDI). The experimental results show that by increasing GDI pressure (PGDI) from 5.5 MPa to 18 MPa, ignition delay (θF) shows a small decrease of 0.68 degrees. The parameters, such as maximum in-cylinder temperature (TMI) and exhaust gas temperature (TEG), each increase by 53.75 K and 13.84 K. An apparent reduction of 59.5% and 36.26% was achieved for the concentrations of particulate number (NP) and particulate mass (MP), respectively. Particulate emissions are effectively reduced by a split GDI strategy with an appropriate range of second injection timing (tGDI2). Under tGDI2 = −260 ºCA, NP and MP concentrations exhibit a relatively lower level. However, by delaying tGDI2 from −260 ºCA to −140 ºCA, there is an increase of more than 60% in NP concentration. The research findings help offer new and valuable insights into optimising particulate number and mass emissions from DFSI engines. Moreover, the findings could contribute novel and valuable insights into the optimisation of particulate emission characteristics in DFSI engines.

Impacts from air pollution on respiratory disease outcomes: a meta-analysis.

Air pollution is widely acknowledged as a significant factor in respiratory outcomes, including coughing, wheezing, emergency department (ED) visits, and even death. Although several literature reviews have confirmed the association between air pollution and respiratory outcomes, they often did not standardize associations across different studies and overlooked other increasingly impactful pollutants such as trace metals. Recognizing the importance of consistent comparison and emissions of non-exhaust particles from road traffic, this study aims to comprehensively evaluate the standardized effects of various criteria pollutants and trace metals on respiratory health. We conducted a comprehensive meta-analysis of peer-reviewed journal articles on air pollution and respiratory outcomes published between 1 January 2000, and 1 June 2024. The study included children (age < 18 years), adults (age ≥ 18 years), and all age groups exposed to criteria pollutants established by the US Environmental Protection Agency National Ambient Air Quality Standards and over 10 trace metals. Using databases, such as PubMed, MEDLINE, Web of Science Core Collection, and Google Scholar, we identified 579 relevant articles. After rigorous screening and quality assessment using the Newcastle-Ottawa Scale, 50 high-quality studies were included. We converted various reported outcomes (e.g., odds ratios, relative risk, and percent increase) to a standardized odds ratio (OR) for comparability and performed meta-analyses using R 4.4.0 and related packages, ensuring the robustness of our findings. Our meta-analysis indicated significant associations between air pollutants and respiratory outcomes. For particulate matter with diameter ≤ 2.5 μm (PM2.5), the overall ORs for children, adults, and combined age groups were 1.31, 1.10, and 1.26, respectively, indicating a consistent positive association. Similar positive associations were observed for particulate matter with diameter ≤ 10 μm (PM10) and other pollutants, with children showing higher susceptibility than adults. The analysis of trace metals also showed significant associations; however, these findings require cautious interpretation due to the small number of studies. Our study supports associations between air pollutants, including non-exhaust trace metals, and respiratory outcomes across different age groups. The findings underscore the need for stringent environmental health policies and further research, especially in regions with higher pollution levels. The future studies should consider long-term and short-term exposures separately and include diverse populations to improve the accuracy and generalizability of the results.

Promoting fine particle removal in cyclone by spray agglomeration and heterogeneous condensation

By adding a spray chamber in front of the cyclone separator, spray agglomeration and heterogeneous vapor condensation were combined to improve the removal effect of the cyclone separator on fine particles, which is used for the deep treatment of high-humidity industrial flue gas and fine particles. Fine particles can form agglomerates through the capture effect of micron droplets, and can also grow in size through heterogeneous vapor condensation in supersaturated water vapor environment, thus being effectively removed by cyclone separators. Supersaturated water vapor environment was a necessary condition for heterogeneous vapor condensation. Numerical simulation results showed that supersaturated water vapor environment can be formed in the spray chamber when the relative humidity of the original flue gas was high, and the higher the relative humidity, the higher the supersaturation and the larger the supersaturation area. The experimental results indicated that spray agglomeration and spray coupling heterogeneous condensation increased the particle removal efficiency of the cyclone separator by 11.6 % and 22.6 %, and the removal efficiency in the 2–4 μm “fish-hook” range was increased by 21.6 % and 41.7 %, respectively. This technology was successfully applied for the first time in the deep treatment of the tail gas in Fluid Catalytic Cracking (FCC) catalyst production industry, which can ensure that the particle emission concentration was within 20 mg/Nm3.