Particle Emission Sources Research Articles

Using native plants to evaluate urban metal pollution and appoint emission sources in the Brazilian Steel Valley region.

In southeastern Brazil, the city of Ipatinga is inserted in the Steel Valley Metropolitan Region, which hosts the largest industrial complex for flat-steel production in Latin America, while also having one of the largest vehicle fleets in the entire country. Since potentially toxic elements (PTEs) are not emitted solely by industries, yet also by vehicular activity, the predominant emission source can be determined by evaluating the ratio between different elements, which are called technogenic tracers. We performed a biomonitoring assay using two tropical legumes, Paubrasilia echinata and Libidibia ferrea var. leiostachya, aiming to assess chemical markers for the origin of emissions in the region, distinguishing between different anthropogenic sources. Plants were exposed for 90days in four urban sites and in a neighboring park which served as reference. After the experimental period, plants were evaluated for trace-metal accumulation. L. ferrea var. leiostachya retained lower amounts of metals associated with vehicular and industrial emission. The opposite was found with P. echinata, a species which should be recommended for biomonitoring of air pollution as a bioaccumulator. Plants of P. echinata were enriched with Fe, Al, Ni, Cr, and Ba, whereas plants of L. ferrea var. leiostachya were enriched with Fe, Cu, and Co. In both species, Fe was the element with which plants were enriched the most. Plants showed highest iron enrichment at Bom Retiro, the site downwind to the steel industry, which has shown to be the main particle emission source in the region.

The research on the particle concentration distribution of directed airflow in cleanrooms for operators.

Existing research of non-unidirectional cleanrooms generally suggests that lower-side return air outlets provide better control effect on indoor particle concentration. As a result, there has been relatively less focus on return air outlets. However, installing return air outlets oriented towards operators as particle emission sources can reduce the impact on process layout and improve space utilization, while also provide less impact from upper particle emission sources on the workbench area. To investigate the characteristics of return air outlet for operators (abbreviated as H), this study compared the particle concentration distribution, non-uniformity, and purification efficiency of return air oultet H and the traditional lower-side (abbreviated as L) return air outlets by experiments and CFD simulations. Based on the theory of mass conservation, the expression of required air supply volume under equivalent cleanroom conditions was derived. Under corresponding experimental and simulation conditions, the particle concentration differences range from 2.0% to 12.7% for return air outlet H and from 12.4% to 33.2% for return air outlet L, and these differences gradually decrease with the air exchange rate (ACH) increases. The results show that ACH = 20 is sufficient for cleanliness requirements with return air outlet H when there is one person in the cleanroom, while a higher rate of ACH = 35 is needed when there are two persons. Although lower-side return air outlets have certain potential for reducing particle concentration in the cleanroom, increasing the air exchange rate remains the most effective method to control indoor particle concentration. Compared to the traditional lower-side return air outlet L, the ranges of the non-uniformity coefficients for return air outlet H and L are 0.50 to 0.67 and 0.45 to 0.53, respectively. The average non-uniformity coefficient differs by 11.9%, and there is not a significant difference in uniformity with more than 20 air changes per hour. The use of return air outlets H only requires an additional 11% of air supply volume to achieve the same cleanliness, demonstrating its effectiveness in controlling particle concentration. It is suitable for cleanrooms with higher requirements for workbenches and for cleanrooms with restricted floor usage or requiring flexible layouts. The study also explores the impact of width of return air outlet oriented towards operators as particle emission sources, the results show that the larger-sized outlets facilitate the particle discharge and control the particle distribution inside the room.

Pion Interferometry with Lévy-Stable Sources in sNN = 200 GeV Au + Au Collisions at STAR

Measurements of femtoscopic correlations in high-energy heavy-ion collisions are used to unravel the space–time structure of the particle-emitting source (the quark–gluon plasma). Recent results indicate that the pion pair source exhibits a power law behavior and can be described well by a Lévy distribution. In this study, Lévy fits were applied to the measured one-dimensional two-pion correlation functions in Au + Au collisions at sNN = 200 GeV. The three extracted source parameters are the Lévy scale parameter, R, which relates to the size of the source; the correlation strength parameter, λ; and the Lévy exponent, α, which characterizes the power law tail of the source. In this paper, we report the current status of the analysis of the extracted Lévy source parameters and present their dependence on average transverse mass, mT, and on centrality.

Bulk flow and correlation measurements at LHCb

Particle correlations are a powerful tool to study the properties of the bulk nuclear matter produced in relativistic heavy ion collisions. The momentum correlations between identical particles originating from the same particleemitting source, referred to as the Bose-Einstein correlations, measure scales that are related to the geometrical size of the source. The two-particle azimuthal angular correlations measure the spatial anisotropy of produced particles, providing information on collective phenomena arising in the dense nuclear medium. This contribution will discuss new LHCb measurements of Bose- Einstein correlations and, for the first time, the collective flow coefficients in the far forward rapidity region.

EVALUATION OF DUST EMISSION RATE FROM LANDFILL MINING ACTIVITIES

Mining operations are one of the most significant sources of particulate emissions in the atmosphere. Landfill mining (LFM) process activities, including excavation, screening, shredding, and equipment handling, have the potential to emit particulate matter into the environment as short-term episodic emissions during operational periods. Previous investigations show that LFM activities can potentially cause human health and environmental impacts through exposure of these emissions. This paper evaluates the dust emission rate of such activities to understand factors responsible for higher emissions rate and determine where any pressure points exist in order to mitigate risk. Nine empirical formulas were adopted from surface mining activities, including point, line, and area sources of activity. Parameters identified in the equations were adjusted to LFM application conditions. From emission results, it is observed that point source activities were the major sources of emission. The study area was divided into multiple phases and one phase cumulative for the maximum/average/minimum point sources emissions over the lifetime of the landfill mining operation calculated in this study are approximately 5.04 tonnes (t) / 3.23 (t) / 1.61 (t), respectively. However, the one phase cumulative for the maximum/average/minimum line sources emissions over the lifetime of the landfill mining operation are approximately 100.8 (kg/m) / 40.32 (kg/m) / 20.16 (kg/m), respectively. Mitigation measures to control high emission rate of LFM related activity, such as utilising tankers or bowsers to spray water around the LFM area, to control airborne emissions, should be considered. The results of this research are expected to inform air dispersion modelling for environmental impact assessment studies of air pollution.

Regenerative braking system effectively reduces the formation of brake wear particles

Brake wear particles (BWPs) are considered one of the most significant non-exhaust particle emission sources from motor vehicles. Previous studies have primarily focused on BWPs from conventional fuel vehicles (CFVs), with limited research available on BWPs from new energy vehicles (NEVs). We developed an independent BWP emission testing system applicable to NEVs and conducted BWP emission tests on representative NEVs and CFVs under various testing cycles via a chassis dynamometer. The BWP emission characteristics of the NEVs equipped with regenerative braking system significantly differed from those of gasoline vehicles. For transient emission characteristics, gasoline vehicles exhibited higher peak concentrations during brake events than brake drag events, while those with regenerative braking exhibited the opposite feature. Under continuous braking, the concentration of ultrafine particles emitted by NEVs was reduced by more than 3 orders of magnitude compared to gasoline vehicles. In terms of single-particle morphology, BWPs could be mainly divided into three categories: carbonaceous particles, iron-rich particles, and mixed metal particles. We obtained realistic emission characteristics of BWPs from NEVs, which could provide data support and a scientific basis for the formulation of relevant emission standards and control measures in the future.

Measuring magnetic susceptibility of particulate matter collected on filters

The magnetic susceptibility (κ) of particulate matter (PM) is a useful tool in estimation concentration of iron-rich particles and provides useful information on the emission sources and pathways of spread of PM in the atmosphere. However, there is currently no established protocol for measuring the magnetic susceptibility of PM collected on filters used in standard monitoring of PM concentration. This paper presents a step-by-step process for collecting PM on filters in automatic samplers and measuring their κ. The procedure outlines requirements for data quality, measurement uncertainty, exposure time and conditions, and the amount of material collected on the filters. The study analyzed a 2-year dataset of magnetic susceptibility measurements by MFK-1 kappabridge (Agico, Czech Republic) for PM10 and PM2.5 collected at two locations, Warsaw and Cracow, in Poland using low-volume PM samplers. By strictly following the procedure for conditioning filters, measuring magnetic susceptibility and mass of PM, the study found that it is possible to obtain repeatable data with good measurement accuracy and acceptable errors. This makes magnetic susceptibility an additional reliable parameter for tracking of emission sources of iron-rich particles. Successful implementation of this magnetic method as a standard procedure for monitoring PM in addition to the PM mass collected on filters could be used to analyze sources of emission of Fe-particles and their contribution to the PM mass, especially in urban and industrial environments.

Towards Cleaner Cities: An Analysis of the Impact of Bus Fleet Decomposition on PM and NOX Emissions Reduction in Sustainable Public Transport

The problem of poor air quality in urban areas has a negative impact on the health of residents. This is especially important during periods of smog. In Poland, as in other countries, the problem of poor air quality, especially during the winter season, is associated with a high concentration of particulate pollutants in ambient air (PM10, PM2.5). Sources of particulate emissions, in addition to solid-fuel boilers, include means of transportation, especially those equipped with diesel engines. In turn, during periods of strong sunshine (spring and summer), the problem of photochemical smog, whose precursors are nitrogen oxides NOX, arises in urban areas. Their main sources of emissions are internal combustion engines. Therefore, to improve air quality in urban areas, changes are being made in the transport sector, among which is upgrading the fleet of urban transport vehicles to low- or zero-emission vehicles, which are more environmentally friendly. In addition, measures that reduce the harmfulness of the transportation sector to air quality include the introduction of clean transportation zones, as well as park-and-ride (P&R) systems. The purpose of this article is to present the results in terms of PM10, PM2.5, and NOx emission reductions, implemented over a period of two years (2021–2022) in the area of the Rzeszow agglomeration, related to the modernization of the suburban bus fleet and the implementation of a P&R system for passenger cars. The results of the study were compared with the value of estimated emissions from coal-fired boilers used for residential heating and hot water, which also contribute to smog. Thanks to the implementation of the project, i.e., the replacement of 52 old buses with new buses of the Euro VI emission class and the construction of new P&R spaces, the total average annual reduction in emissions amounted to approximately 703.6 kg of PM10, approximately 692.7 kg of PM2.5, and a reduction of approximately 10.4 tons of NOX.

Chemical characteristics of fine tire wear particles generated on a tire simulator

Tire wear is one of the major sources of traffic-related particle emissions, however, laboratory data on the components of tire wear particles (TWPs) is scarce. In this study, ten brands of tires, including two types and four-speed grades, were chosen for wear tests using a tire simulator in a closed chamber. The chemical components of PM2.5 were characterized in detail, including inorganic elements, water-soluble ions (WSIs), organic carbon (OC), elemental carbon (EC), and polycyclic aromatic hydrocarbons (PAHs). Inorganic elements, WSIs, OC, and EC accounted for 8.7 ± 2.1%, 3.1 ± 0.7%, 44.0 ± 0.9%, and 9.6 ± 2.3% of the mass of PM2.5, respectively. The OC/EC ratio ranged from 2.8 to 7.6. The inorganic elements were dominated by Si and Zn. The primary ions were SO42− and NO3−, and TWPs were proven to be acidic by applying an ionic balance. The total PAHs content was 113 ± 45.0 μg g−1, with pyrene being dominant. In addition, the relationship between the chemical components and tire parameters was analyzed. Inorganic elements and WSIs in TWPs were more abundant in all-season tires than those in winter tires, whereas the content of PAHs was the opposite. The mass fractions of OC, Si, and Al in the TWPs all showed increasing trends with increasing tire speed grade, but the PAHs levels showed a decreasing trend. Ultimately, to provide more data for further research, a TWPs source profile was constructed considering the tire weighting factor.

Kaon Femtoscopy with Lévy-Stable Sources from sNN=200 GeV Au+Au Collisions at RHIC

Femtoscopy has the capacity to probe the space-time geometry of the particle-emitting source in heavy-ion collisions. In particular, femtoscopy of like-sign kaon pairs may shed light on the origin of non-Gaussianity of the spatial emission probability density. The momentum correlations between like-sign kaon pairs are measured in data recorded by the STAR experiment, from sNN=200 GeV Au+Au collisions at RHIC, BNL. Preliminary results hint at the possible existence of non-Gaussian, Lévy-stable sources, with the likely presence of an anomalous diffusion process in the signal for the identically charged kaon pairs so produced. More statistically significant studies at lower centre-of-mass energies may contribute to the search for the critical end point of QCD.

Femtoscopic Correlation Measurement with Symmetric Lévy-Type Source at NA61/SHINE

Measuring quantum-statistical, femtoscopic (including final state interactions) momentum correlations with final state interactions in high-energy nucleus-nucleus collisions reveal the space-time structure of the particle-emitting source created. In this paper, we report NA61/SHINE measurements of femtoscopic correlations of identified pion pairs and describe said correlations based on symmetric Lévy-type sources in Ar+Sc collisions at 150A GeV/c. We investigate the transverse mass dependence of the Lévy-type source parameters and discuss their possible interpretations.

Interacting Colour Strings Approach in Modelling of Rapidity Correlations

In this paper, using the concept of multi-pomeron exchange, we develope a Monte Carlo model of interacting quark–gluon strings acting as particle-emitting sources aimed at describing inelastic proton–proton interactions at high energies. The implemented 3D (three-dimensional) dynamics of colour string formation resulted in their finite length in the rapidity space and in the fluctuating event-by-event spatial density. Thus, this results in string cluster formation because of the fusion mechanism and the appearance of long-range multiplicity and mean transverse momentum (mean-pT) correlations in rapidity. We study, via the pseudorapidity dependence, the sensitivity to the details of the 3D dynamical formation of strings for several observables such as the forward–backward correlation coefficient value, strongly intensive quantity, Σ, and the “almost” strongly intensive observable, the variance, σC2, of the distribution of the asymmetry coefficient, C. The strongly intensive quantity Σ is used in this study to suppress trivial statistical fluctuations in the number of particles emitting similar types of sources and to reveal the intrinsic fluctuations of a single source. We demonstrate the connection between Σ and such often used observables as cumulants, factorial cumulants, and σC2. We stress the importance of the contribution of “short” strings and the event asymmetry of the initial conditions on the long-range correlation measures. We argue that string cluster formation because of the fusion mechanism explains the collective effects seen in multiplicity and transverse momentum–multiplicity, ⟨pT⟩–N, long-range correlation functions.

Effects of organic carbon/elemental carbon and particle size on inhalation bioaccessibility of particle-bound PAHs

Bioaccessible fractions of particle-bound hydrophobic organic compounds (HOCs) are critical to evaluating human inhalation exposure risk. However, the key factors for controlling the release of HOCs into the lung fluid are not adequately examined. To address this issue, eight particle size fractions (0.056–18 μm) from different particle emission sources (barbecue and smoking) were collected and incubated with an in vitro method for determining inhalation bioaccessibilities of polycyclic aromatic hydrocarbons (PAHs). The bioaccessible fractions of particle-bound PAHs were 35–65% for smoke-type charcoal, 24–62% for smokeless-type charcoal, and 44–96% for cigarette. The size distributions of bioaccessible fractions of 3–4 ring PAHs were symmetric with the patterns of their masses, characterized as a unimodal distribution with both the trough and peak at 0.56–1.0 μm. Analysis from machine learning showed that chemical hydrophobicity appeared to be the most significant factor affecting inhalation bioaccessibility of PAHs, followed by organic carbon and elemental carbon contents. Particle size seemed to have little effect on the bioaccessibility of PAHs. A compositional analysis of human inhalation exposure risk from total concentration, deposition concentration, and bioaccessible deposition concentration in alveolar region showed a shift in the key particle size from 0.56−1.0 μm to 1.0–1.8 μm and an increasing in the contributions of 2–3 ring PAHs to risk for cigarette due to the high bioaccessible fractions. These results suggested the significance of particle deposition efficiency and bioaccessible fractions of HOCs in risk assessment.

Particle number, mass, and black carbon emissions from fuel-operated auxiliary heaters in real vehicle use

Fuel-operated auxiliary heaters (AHs) are frequent solutions to heat the vehicle engines and cabins in cold areas. Particulate exhaust emissions of AHs are unregulated; therefore, their contribution to local air quality and thus human health and even the global emissions budget is unknown. Experiments for studying the AH-originated emissions were performed under Finnish winter conditions mimicking real-world use for six selected vehicles with original AHs installed, including both gasoline- and diesel-powered heaters. We present quantitative results of particle number emissions down to 1.3 nm, particle size distributions, particulate mass, and black carbon, and compare to gaseous emissions. The start-up and shutdown phases showed the highest particle peaks, while the particle concentrations were stable between these. The mean particle number, mass and BC emission factors were found to be as high as 590×10 12 kg fuel −1 , 33 mg kg fuel −1 and mg 18 kg fuel −1 for gasoline-operated heaters and 560×10 12 kg fuel −1 , 20 mg kg fuel −1 and 12 mg kg fuel −1 for diesel-operated heaters. Comparing total number of particles larger than 23 nm emitted during vehicle preheating with AH to vehicle tailpipe emissions during drive shows that a typical heating cycle emits an equal number of particles to drive dozens or even thousands of kilometers. • Emissions from auxiliary vehicle heaters were measured under sub-zero conditions. • Auxiliary heaters can be noteworthy sources of particle emissions from vehicles. • Gasoline heaters produced mostly higher emissions than diesel heaters. • Pre-heating particle emissions were comparable to driving of notably long routes.

Accounting dust emission in the system of management of ambient air quality

Introduction. The fulfillment of effective measures to manage the level of dust pollution in the atmospheric air of settlements requires correct hygienic assessments of the situation and reliable data on the sources of particulate emissions. The purpose of the study was to substantiate what is need to take into account the entire set of solid emitted components when conducting hygienic assessments of the situation, including the consideration and approval of draft standards for permissible emissions and projects of sanitary protection zones. Materials and methods. On the example of a large industrial enterprise, calculations of the dust emissions dispersion were made with and without taking into account the total mass of solid components. Source parameters are taken according to the enterprise inventory list. Dispersion calculations were carried out using the standardized program “Ecolog-City”. Results. For each individual solid substance at the border of the sanitary protection zone and at the points of the nearest housing no violations of hygienic standards were established to be recorded. The situation was characterized as normative, not requiring measures to improve the safety of the population. The total release of the solid component of emissions (TSP) created an excess of the hygienic standard for the group “suspended substances” (0.5 mg/m3) at the border of the sanitary protection zone. The zone of excess pollution (more than 1 MPC) extended to the residential area. The level of pollution calculated from the totality of solid substances was satisfactorily corresponded with the data of instrumental measurements. Limitations. The limitation of the study is related to the fact that the obtained results characterize a particular enterprise, however, the principal approaches used can be applied to any similar studies. Conclusion. It seems appropriate to harmonize the concept of “suspended matter” with the definition adopted by the World Health Organization, establishing that suspended matter is the total amount of solid particles of organic and inorganic substances. Fixing such a concept in sanitary rules and regulations ensures the correctness of the hygienic assessment of the situation, the comparability of calculated and natural data, the absence of contradictions between the established emission standards for each type of dust and the results of a health risk assessment (performed taking into account the sum of all particulate matter). The use of MPCs for various types of dust remains an important tool for identifying emission sources and preventing the negative impact of dusts with carcinogenic or highly toxic properties.

Particle Multiplicity Fluctuations and Spatiotemporal Properties of Particle-Emitting Source of Strongly Interacting Matter for NICA and RHIC Energies

The results of the model analysis of hadron femtoscopic correlations and factorial moments of particle multiplicity in heavy ion collisions for the energy range of the Beam Energy Scan (BES) program at RHIC and future NICA collider are presented. For this purpose, the simulation of Au+Au collisions at center-of-mass energies 7.7 and 11.5 GeV per nucleon pair using the UrQMD, vHLLE+UrQMD (with the crossover and first-order equation of states), and HYDJET++ event generators was performed. The sensitivity of pion and kaon correlation radii and the dependence of the factorial moments on heavy ion beam energy to quark–hadron phase transition details was studied. In addition, the possible influence of some relevant detector effects on the corresponding experimental observables is discussed.

Significant reduction of ultrafine particle emission fluxes to the urban atmosphere during the COVID-19 lockdown

The worldwide restrictions of social contacts that were implemented in spring 2020 to slow down infection rates of the SARS-CoV-2 virus resulted in significant modifications in mobility behaviour of urban residents. We used three-year eddy covariance measurements of size-resolved particle number fluxes from an urban site in Berlin to estimate the effects of reduced traffic intensity on particle fluxes. Similar observations of urban surface-atmosphere exchange of size-resolved particles that focus on COVID-19 lockdown-related effects are not available, yet. Although the site remained a net emission source for ultrafine particles (UFP, Dp < 100 nm), the median upward flux of ultrafine particles (FUFP) decreased from 8.78 × 107 m−2 s−1 in the reference period to 5.44 × 107 m−2 s−1 during the lockdown. This was equivalent to a relative reduction of −38 % for median FUFP, which was similar to −35 % decrease of road traffic intensity in the flux source area during that period. The size-resolved analysis demonstrated that, on average, net deposition of UFP occurred only during night when particle emission source strength by traffic was at its minimum, whereas accumulation mode particles (100 nm < Dp < 200 nm) showed net deposition also during daytime. The results indicate the benefits of traffic reductions as a mitigation strategy to reduce UFP emissions to the urban atmosphere.

Multipomeron Model with Collective Effects for High-Energy Hadron Collisions

We propose the generalized multipomeron exchange model for multiparticle production in high-energy proton–proton, proton–nucleus and heavy-ion collisions. For all of these systems, we consider collectivity effects based on the quark–gluon string fusion concept, where new types of particle-emitting sources—strings with higher tension—are produced. We obtained the model parameters using the data on the multiplicity dependence of the mean transverse momentum of charged particles in pp and pp¯ collisions over a wide energy range (from ISR to LHC). We calculated the yields of strange, multi-strange and charm particles as a function of multiplicity for pp, p-Pb and Pb-Pb collisions at the LHC energy and compared the results with the experimental data.

FINE PARTICLES EMISSION SOURCE PROFILES FOR A SEMI-ARID URBAN CENTER: KEY MARKERS AND SIMILARITY TESTS

Source apportionment studies rely on source emission profiles, which in some instances are locally scarce or non-existent. Thus, estimations are done using profiles obtained from other geographical sites, which brings a certain degree of uncertainty in the outcomes of such studies. This work presents the results of near-field measurement of 12 types of fine particle emission sources to develop local-region source profiles in the Monterrey Metropolitan Area. The source profiles include a chemical characterization of trace elements and carbonaceous fraction. A statistical analysis based on the Pearson distance and similarity identity distance was conducted to ensure the uniqueness of each source profile. Overall, the most dominant species in the profiles were organic and elemental carbon, and elemental sulfur, whereas the least abundant were transition metals. The meat-cooking operations profiles exhibited the highest organic carbon to elemental carbon ratios, which were 7-40 times higher than those for biomass burning and vehicle exhausts profiles. The urban construction profile was dominated by crustal elements, while the suburban area profile exhibited an internal mixing with anthropogenic compounds. The source profiles in this study were distinguishable, as determined by preliminary tests for each pair of chemical source profiles. These profiles could be used to implement receptor models in urban sites with similar characteristics.

Strange hadron correlations in heavy-ion collisions at RHIC energies and below

Geometry and dynamics of the particle-emitting source in heavy-ion collisions can be inferred via the femtoscopy method. Two-particle correlations at small relative momentum exploit Quantum Statistics and the Final State Interactions (Coulomb and strong), which allow one to study the space-time characteristics of the source of the order of 10−15 m and 10−23 s. Femtoscopic measurements allow one also to study FSI, especially the strong one, which is unknown for many two-particle systems. The RHIC program covers a significant part of the QCD phase diagram using collisions of Au nuclei for several beam energies from 7.7 to 200 GeV for which baryon-rich region is studied via femtoscopy. These measurements complement those obtained from AGS, SPS, and SIS experiments. Strange hadron measurements together with nonstrange ones provide complementary information about source characteristics. Strangeness is a significant observable for many regimes of collision energies providing a complete view of strangeness production in heavy-ion collisions. These proceedings shows the femtoscopic measurements of various strange particle combinations at different collision energies and centralities of the collision.