Hasil untuk "Hazardous substances and their disposal"

Травин, С.О.

На примере известной жесткой схемы реакций Робертсона показано практическое применение различных методов интегрирования прямой задачи химической кинетики. Проведено сравнение одношаговых и многошаговых методов, явных и неявных схем решения и разработан оригинальный подход, сочетающий применение метода Адамса на начальной стадии развития реакции с переходом к системе дифференциально-алгебраических уравнений, решаемых методом Эйлера после достижения стационарного режима. Достигнуто рекордно короткое общее время численного решения задачи на интервале времен свыше 20 порядков. Предложенный метод превосходит традиционные алгоритмы по быстродействию не менее, чем в сто раз.

Delaram Darvishpour, Hossain Hassani, Veronese Guido

Background: The aim of the current research is to study the views of first grade elementary school teachers in Yazd about the challenges of working with single-child students. Methods: In this qualitative descriptive study, 15 primary school teachers were selected through theoretical sampling. The criteria for determining sample size were achieving the theoretical saturation in extracted categories. The inclusion criteria were willingness to participate and at least one academic year of teaching experience with single-child students in the classroom. Data were collected through semi-structured face-to-face interviews conducted over a period of 3 months. Data were analyzed using qualitative content analysis with a conventional (inductive) approach. To ensure research rigor, the authors addressed trustworthiness through four criteria: (1) credibility (via member checking and peer debriefing), (2) transferability (thick description of context), (3) dependability (audit trail of research process), and (4) confirmability (researcher reflexivity journals). Triangulation was achieved through multiple data sources and analyst cross-checking. Results: Three core themes emerged from the analysis, with twenty distinct subthemes illuminating the challenges faced by single-child students in classroom settings:Social Competency Deficits (Social isolation, peer incompatibility, egocentric behaviors, conflict resolution difficulties, rule-compliance challenges, friendship formation barriers), Developmental Vulnerability Traits (Depressive tendencies, obsessive behaviors, low self-efficacy, poor resilience, indecisiveness, digital overreliance, self-regulation gaps, delayed social acceptance, passive listening, accountability deficits),Emotional Regulation Difficulties (Separation anxiety, perceived deviance distress, emotional dysregulation, excessive validation-seeking).    Conclusion: The study reveals that single-child students' developmental trajectories are significantly shaped by their limited peer socialization opportunities, which  are manifested in three interrelated domains: underdeveloped social competencies, heightened vulnerability in personality development, and impaired emotional regulation capacities. These findings suggest that the absence of sibling relationships may create distinct socialization challenges that classroom environments must intentionally address through targeted pedagogical interventions.

Narin Printarakul, Napaporn Paennoi, Weeradej Meeinkuirt

The effects of copper (Cu) and cadmium (Cd) accumulation on growth and development of Scopelophila cataractae (Mitt.) Broth., Pottiaceae, were investigated over 24 weeks. Moss samples were grown on modified hydroponic medium supplemented with Cu and Cd. Cu markedly promoted the transition from chloronema to caulonema and showed a significantly higher proportion (95.5 %) at 800 µM CuSO₄. The greatest bud and gametophore formation was observed in the 400 µM CuSO₄ treatment, with 130 buds per 25 mm². In contrast, Cd restricted filaments to the chloronema stage, reduced average chloroplast numbers per cell (from 75 to 34.5 under 800 µM CdCl₂), and induced large vacuolar vesicles, reflecting cellular stress. Relative growth rates were 7.1, 10.7 and 16.2 mg g⁻¹d⁻¹ for 800 µM CuSO₄, 800 µM CdCl₂ and control, respectively, indicating strong growth inhibition by heavy metals at high accumulation. Co-exposure of low Cu with Cd increased Cd accumulation (2188–16,027 mg kg⁻¹) and mitigated Cd toxicity. High metal accumulation (>1000 mg kg⁻¹ for Cd, >10,000 mg kg⁻¹ for Cu), protonemal growth and development were generally suppressed. These findings highlight the adaptive strategies of S. cataractae in coping with heavy metal stress and its potential as a bioindicator for metal-contaminated environments.

Javed Ahmad, Mohammad Affan Baig, Arlene Asthana Ali et al.

Arsenic contamination of soils and groundwater affects nearly 106 countries, exposing an estimated 230 million people worldwide to a range of health risks including cancer, cardiovascular disease, diabetes, etc. It also poses significant risks to plants such as inhibited growth, reduced crop yields, and soil health degradation. This study investigates the arsenic (As)-induced changes in dynamics of proteome, sulfur metabolism, antioxidant enzymes and changes in stress tolerance mechanisms in Trigonella foenum-graecum under different concentrations. Hydroponically grown 30-day-old plants were exposed to 0, 25, 50, 75, and 100 µM As for 10 days. The results showed increased oxidative stress and reduced growth at higher As concentrations. Enzymes related to thiol metabolism, including ATP sulfurylase and serine acetyltransferase, were significantly upregulated at 50 and 100 µM As, alongside increased cysteine and glutathione content linked to the upregulation of S-deficiency-induced 2 isoform X2 protein. Antioxidant enzymes (SOD, APX, CAT, GR, GPX, and GST) also exhibited enhanced activity. Proteomic analysis revealed 46 differentially expressed protein spots, including proteins involved in growth and photosynthesis, such as gibberellin 20-oxidase and RuBisCO. Defence proteins like trehalose phosphate phosphatase, calmodulin, and pectinesterase were upregulated, aiding stress tolerance. Sulfur metabolism proteins, such as glutathione S-transferase, were activated to counteract oxidative stress. Metallothioneins (MTs) were notably upregulated, contributing to arsenic detoxification. Transport proteins, including ABC transporters and ATP synthase beta subunits seems to play important roles in arsenic resistance. Additionally, proteins involved in protein degradation and redox balance, such as the RING finger protein and selenoprotein W1, supported the plant's adaptive response. These findings highlight the complex proteomic changes that enable T. foenum-graecum to tolerate arsenic stress and enhance its phytoremediation potential.

Laleh Gharishvandi, Masoud Lotfizadeh, Mahnaz Jafari et al.

Background: Child abuse is a major psychological and social problem in all countries and is affected by a set of cultural, social, and family factors as well as some characteristics of children. This study was conducted to determine the prevalence of child abuse among primary school students in Shahrekord. Methods: This cross-sectional study was conducted in 2024 on 245 students from fourth to sixth grades in public schools of Shahrekord selected through cluster sampling. Four clusters were randomly selected from all primary schools in this area, 4 clusters were randomly selected and then the final sample (126 females) was randomly selected from the above sections. Hosseinkhani researcher-made Child Abuse Questionnaire was used in this study. Chi-square, t-test, analysis of variance, and correlation coefficient were used to analyze the data. Results: The results of the study showed that 30.6% of children experienced physical abuse, 56.4% of them had experienced emotional abuse, and 99.6% experienced negligence as a type of abuse. The data showed only a significant relationship between negligence and fathers' education (p=0.032), so increasing fathers' education level led to more negligence. There was a significant relationship between having an experience of emotional-psychological abuse and having an experience of physical abuse (P <0.001), i.e, students who had higher score in emotional-psychological dimension reported more child abuse in physical dimension. Conclusion: Considering the high prevalence of child abuse among students, it is necessary to take steps to reduce child abuse by educating parents on correct pedagogical methods.

Xiaohan Zhang, Ying Zhang, Yongzheng Ma et al.

Microplastics (MPs) have received great concern in recent years, and whether the bacteria carried by traveling MPs would cause ecological risks is a hot topic for debate. The colonized bacteria (i.e., hitchhikers) on traveling MPs which become invasive species in the new environment, need to be completed in three steps: arriving, falling, and growing. However, most previous studies only focused on the first step, which we think is insufficient to discuss species invasion. Thus, in this frontier review, we reviewed the progress of the current research on the uniqueness of bacterial communities on MPs, and we summarized that the uniqueness of the plastisphere was not as high as previously thought. Moreover, we explained why the three steps were necessary to complete the bacterial species invasion. Furthermore, we analyzed the technical difficulties hindering discussing MPs as invasive species carriers, as well as the perspectives in future research. Therefore, this frontier review presents new insights into the role of MPs as bacterial carriers, and suggests study directions for future research.

João Pereira Santos, David Amouroux, Vera I. Slaveykova

Bioaccumulation of dissolved elemental mercury (DGM) by various organisms has been demonstrated, but no study has shown its uptake and sequestration by phytoplankton species. The present study aims to investigate the accumulation of mercury by phytoplankton species exposed to DGM. Diatoms (Cyclotella meneghiniana and Navicula pelliculosa) and green algae (Chlamydomonas reinhardtii and Haematococcus pluvialis) were exposed to constant high level of atmospheric gaseous Hg (∼7.7 µg m−3). Total mercury concentrations (THg) in the medium (dissolved fraction) and algae cells (cellular fraction) were determined using cold vapor atomic fluorescence spectroscopy. Results revealed a partitioning of Hg(0) between the atmosphere and phytoplankton cultures, with THg predominantly found in the algae cells. THg in the algae cultures decreased in the order: C. reinhardtii > H. pluvialis > N. pelliculosa > C. meneghiniana. However, the cellular concentration (mol cell−1) decreased in the order: H. pluvialis > C. reinhardtii > C. meneghiniana > N. pelliculosa. These results highlight species specificity in Hg accumulation upon exposure to DGM, further linked to the phytoplankton surface area. Our findings reveal for the first time that phytoplankton species significantly influence the partitioning of atmospheric Hg(0) in aquatic environments, with important implications for the understanding of the aquatic mercury cycle.

Nader Aghakhani, Alireza Nikoonejad, Fariba Hosseinzadegan

No Abstract

Hossein Tavangar, Marjan Alichi, Zahra Pourmovahed

Background: Premature birth is a global health issue leading to major stress in mothers that will be able to get answers to many of their questions at home through a phone call. This study aimed to investigate the effect of telephone health training on perceived stress of mothers with premature infants discharged from hospital. Methods: This quasi-experimental study was conducted on 60 mothers referring to Shohada-ye Kargar Hospital (Yazd, Iran) in 2022. They were selected using a purposive sampling method and then randomly assigned to the control and intervention groups. Data collection was accomplished with the Perceived Stress Questionnaire and demographic questionnaire. Telephone training was performed in intervention group. The control group received the ordinary care at discharge time. Data were analyzed with SPSS22 using paired t-test, independent t-test, and chi-square test. Results: The mean perceived stress of mothers was 25.10 ± 2.32 and 25.33 ± 3.12, in the intervention and control group prior to the intervention, respectively. These scores were 21.24 ± 1.83 and 24.14 ± 2.81, respectively after the intervention, and it decreased significantly in the intervention group (P = 0.03). Conclusion: Telephone health training is regarded as an efficient and low-cost method for reducing perceived stress of mothers with premature infants discharged from the Neonatal Intensive Care Unit.  Improving maternal and neonatal health are suggested.

Rethinam Senthil

The removal of chrome waste (CW) has been identified as a significant environmental problem due to chromium's toxicity. This study tried to make a regenerated flexible sheet (RFS) with a leather alternative effect from chrome waste powder (CWP), cardboard waste fiber (CBWF), and protein binder (PB) fabricated by the hydraulic wet and hot press method. The prepared RFS was characterized by its High-resolution scanning electron microscopy (HR-SEM), thermo gravimetric analysis (TGA), mechanical analysis, and biodegradation properties. The result showed the strong binding achieved with fiber/polymer membrane for RFS. In this regard, RFS with suitable mechanical properties such as tensile strength (37.54 ± 1.32 MPa), elongation at break (33.64 ± 0.52 %), flexibility (5.34 ± 0.67 %), water absorption (27.74 ± 1.56 %), and water desorption (27.46 ± 0.76 %) properties. RFS possessed the required mechanical properties for leather sheet production and it was also biodegradable. The study proves that these composites could be successfully used for the production of cost-effective leather goods and footwear production. Production of useful byproducts from waste is income generating and at the same time reduces environmental pollution and a feasible technology for waste recycling has been proved in this study.

Tarmizi Taher, Zhongliang Yu, Elisabeth Kartini Arum Melati et al.

The development of adsorbents capable of adsorbing both anionic and cationic dyes in wastewater treatment remains a challenge. This study presents the successful fabrication of Nb2O5-MgAl layered double hydroxide (LDH) nanocomposites for the effective removal of methylene blue (MB) and Congo red (CR) dyes via a one-step hydrothermal method. Incorporating a small amount of Nb into MgAl-LDH proved to be an effective strategy for creating nanocomposite materials with dual characteristics. The material’s morphological and crystalline structures were confirmed using FESEM-EDS and XRD. Incorporating Nb during the material preparation led to a remarkable enhancement in the material’s adsorption capacity - up to 3.4-fold and 9.0-fold increases for CR and MB, respectively. The kinetic and point zero charge analysis confirmed that the adsorption of the dyes onto the adsorbent surfaces occurred via an ionic interaction mechanism. These findings offer a promising alternative for fabricating dual-functional adsorbents, enhancing the effectiveness of dye removal in wastewater treatment technologies.

Olutomiwa Binuyo

Background: The 2018 National Demographic Health Survey (NDHS) revealed that out of the current non-users of contraceptives amongst married women, only 38% of them made their own decision to abstain. The remaining 62% either decided jointly with their partner or the partner solely decided for them. This elicits the notion that social expectations within reference networks could influence the use of modern contraceptives (MCs) in Nigeria. Methods: 16 structured qualitative interviews were used to gather the beliefs, attitudes and social expectations of the respondents as regards the non-use of MCs between March and June 2020. Through snowballing sampling method, residents in the Ibadan Metropolis, southwest Nigeria responded to the hypothetical scenarios presented by the vignettes during interviews. Data were analysed using the Social Norms Analysis Plot framework. This framework serves as the checklist for the reporting of findings.  Basic ethical principles were upheld throughout the study. Results: Seven categories and five main themes emerged from this study. These categories include gender norms, social influence, peer pressure, myths, misconceptions, awareness and pluralistic ignorance. The themes were generated using the Social Norms Analysis Plot framework and they include empirical expectation, normative expectations, sanctions, sensitivity to sanctions and exceptions. The majority of the respondents strongly believe that most women in their community will not use contraceptives simply because of their male partners and friends. Out of those who do not use MCs due to social expectations, it was seen that the majority personally support its use. Conclusion: To promote the uptake of modern contraceptive use in Southwest Nigeria, it is important to update people’s social expectations. The findings of these study studies are relevant for policymakers and civil society organizations in designing effective intervention reproductive health programs in different regions of Nigeria (especially areas of lower use of modern contraceptives).

Neda Kouravand, Monika Motaghi

Background: Strategic knowledge management is widely recognized as a pivotal resource for the success of contemporary organizations. Self-management skills of managers are instrumental in fostering an organization’s growth and sustainability in the long run. The present study explores the relationship between strategic knowledge management and self-management and organizational development among managers in Social Security (Tamin-e Ejtemaei) Hospitals in the city of Isfahan. Methods: This was a practical, descriptive, and survey-based research with a correlational design, classified as field study. This study was conducted in 2022 on 117 managers of Tamin-e Ejtemae’i hospitals (Dr. Ali Shariati Hospital and Dr. Gharazi Hospital) in the city of Isfahan. Strategic knowledge management was measured using Lopez-Nicholas and Mariano-Cardenas questionnaire, self-management was evaluated through SMSQ questionnaire devised by Houghton and Neck, and organizational development was assessed using the Lok and Crawford questionnaire. The collected data underwent analysis using SPSS 26 software and the statistical methods applied Spearman’s rank correlation test, Tukey’s test, homogeneity of variance, Kolmogorov-Smirnov test, regression analysis, T-test, and significance level was set at 0.05. Results: A significant correlation was observed between strategic knowledge management and self-management (P-value = 0.027), strategic knowledge management and organizational development (P-value = 0.000), and between organizational development and self-management (P-value = 0.000). Regarding organizational development, the highest average score was associated with relationships (a score of 20.5172); for strategic knowledge management, explicit knowledge received the highest average score (a score of 21.2632), and concerning self-management, personal goal setting obtained the highest average score (a score of 20.1810). Conclusion: Investing in strategic knowledge management, focusing on intellectual capacities, and increasing managers’ self-management improves performance and organizational development in hospitals.

Taiwo Ayorinde, Christie M. Sayes

Titanium dioxide (TiO2) is a metal oxide that occurs naturally when titanium reacts with airborne oxygen. It has various attractive and beneficial properties, such as thermal stability, photocatalysis potential, and resistance to ultraviolet radiation. As a result, it is widely used in industrial processes and commercial products. The physicochemical properties of TiO2 can vary depending on the material's primary particle size, crystallinity, and formulation. Different properties have been found to cause different toxicological responses. While most studies have focused on the effects of exposure to nano-TiO2, little attention has been given to other relevant TiO2 materials. In this review, we examine the toxicological profile of both titanium dioxide nanoparticles and pigmentary TiO2. This review aims to provide reliable information on titanium dioxide toxicity for public and private stakeholders to use in risk assessments.

Mark L. Brusseau

Soil and porewater concentrations measured for multiple PFAS were compiled from three field studies. The soil:porewater concentration ratios were shown to be functions of molar volume for all three data sets. Remarkable consistency was observed between the three sets of field-based measurements, indicating that PFAS distributions in the three soil systems exhibited similar magnitudes of overall retention. The relative contributions of solid-phase sorption and air-water interfacial adsorption to total retention were examined. The contribution of air-water interfacial adsorption was greater than that of solid-phase sorption for the longer-chain PFAS, whereas it was less than that of solid-phase sorption for the shorter-chain PFAS. These results show that the relative contributions of the two processes can vary as a function of the particular PFAS when the solid-phase sorption functionality deviates from that of air-water interfacial adsorption. This might occur for example when sorption is influenced by addition mechanisms beyond hydrophobic interaction, or when sorption and/or adsorption are nonlinear. Based on the results from all three data sets, soil concentrations are likely to be smaller than porewater concentrations for the shortest-chain PFAS. Conversely, soil concentrations will generally be significantly greater than porewater concentrations for longer-chain PFAS. The results from this study have implications for characterizing and evaluating PFAS distributions in vadose-zone soils.

Saeed Bashirian, Majid Barati, Maryam Afshari et al.

Background: With the closure of schools as a result of the social distancing plan, the negative emotions that individuals experience became complicated. Therefore, the present study provided a deep understanding of the concerns and stresses of parents, students, and teachers about the process of social distance planning and reopening of schools during COVID-19 pandemic. Methods: This directed qualitative content analysis was conducted in 2020. The data for this study were collected through semi-structured interviews with teachers (n=28), students (n=20), and their parents (n=32) in Tuiserkan County. Sampling was performed by purposeful sampling method with the maximum variation. Data analysis was performed simultaneously with data, collected by content analysis method. Results: In general, 90% of participants were stressed and concerned about the social distancing plan and the reopening of schools during Covid-19 pandemic. During data analysis, 74 primary codes, 13 sub-themes and 4 themes were obtained. The themes included predisposing factors (knowledge and attitude), reinforcing factors, enabling factors, and quality of life. Conclusion: Identifying and explaining the concerns and stress of parents, students and teachers about the process of social distance planning and reopening of schools during infectious diseases such as COVID-19 pandemic will help policy-makers and administrators for planning and interventions related to this. Background: With the closure of schools as a result of the social distancing plan, the negative emotions that individuals experience became complicated. Therefore, the present study provided a deep understanding of the concerns and stresses of parents, students, and teachers about the process of social distance planning and reopening of schools during COVID-19 pandemic. Methods: This directed qualitative content analysis was conducted in 2020. The data for this study were collected through semi-structured interviews with teachers (n=28), students (n=20), and their parents (n=32) in Tuiserkan County. Sampling was performed by purposeful sampling method with the maximum variation. Data analysis was performed simultaneously with data, collected by content analysis method. Results: In general, 90% of participants were stressed and concerned about the social distancing plan and the reopening of schools during Covid-19 pandemic. During data analysis, 74 primary codes, 13 sub-themes and 4 themes were obtained. The themes included predisposing factors (knowledge and attitude), reinforcing factors, enabling factors, and quality of life. Conclusion: Identifying and explaining the concerns and stress of parents, students and teachers about the process of social distance planning and reopening of schools during infectious diseases such as COVID-19 pandemic will help policy-makers and administrators for planning and interventions related to this.

Owen P. Missen, Ella R. Lausberg, Joël Brugger et al.

Tellurium (Te) is a Critical Element that is toxic to microorganisms and humans alike, most notably in its soluble oxyanionic forms. To date, the biogeochemical behaviour of Te in Earth’s surface environment is largely unknown. Here, we report the discovery of elemental Te nanoparticles (Te NPs) in regolith samples using Single-Particle Inductively Coupled Plasma Mass Spectroscopy. Tellurium NPs were detected in both proximal and distal locations (bulk concentrations >4 ppm) relative to weathering Te ores. Synchrotron X-ray Fluorescence Mapping and X-ray Absorption Spectroscopy showed that bulk Te in the regolith is generally associated with Fe (oxyhydr)oxides and clay minerals, and mostly found in the oxidation states +IV and +VI. Although Te NPs account for less than 2 mol‰ of Te in our samples, their detection provides evidence for the active biogeochemical cycling of Te in surface environments. Te NPs are reactive and are likely to have formed in situ in distal samples, most likely via microbially-mediated reduction. Hence, the presence of Te NPs indicates the potential for release of toxic soluble forms of Te even in environments where most Te is “fixed” in forms such as Fe (oxyhydr)oxides that have low solubility and poor bioavailability.

Afolabi Fasoranti Joseph

Background: Hepatitis B, which is caused by the Hepatitis B virus (HBV), is a global health problem that has resulted in high morbidity and mortality with knowledge and awareness about the occurrence and mode of transmissions relatively low among the populace. Therefore, this study examined knowledge on the mode of transmission and preventions of hepatitis B among undergraduate students in Lagos, Nigeria. Methods: The cross-sectional descriptive research was used, and a multi-stage sampling technique was adopted to select three hundred respondents which comprised male and female from three tertiary institutions in Lagos state in 2019. Hepatitis B Knowledge Questionnaire with a reliability index of 0.74 was used for data collection. The descriptive statistics of frequency count and percentages was used to analyse the demographic characteristics of respondents while the chi-square test was used to determine associations between categorical variables. Results: The results revealed that a high proportion of the respondents had poor knowledge about the transmission and prevention of hepatitis B. The result revealed that the p-value ≤ 0.05 was considered statistically insignificant. Therefore, the study revealed that there is no significant relationship between gender and hepatitis B. Conclusion: A critical level of public awareness and vaccination coverage, particularly among students, is essential to decrease Lagos' burden.

Denis Ndanguza, Angelique Nyirahabinshuti, Consolee Sibosiko

The toxic and hazardous waste have dangerous properties and often cause a harmful effect on human health and the environment. Waste products generated from chemical industries and hospitals are the most classified into hazardous waste. Therefore, we are interested in modeling and analysing a dynamical system where intoxication on the population occurs due to mismanagement of such produced wastes. The model explains the relationship between the density of individuals in a certain area, waste generation and concentration of the toxic. Initially, we simulated synthetic data and estimated parameters using Least Square method. The stability analysis around critical points, bifurcation and sensitivity analysis are carried out and exhibit that once the population is growing, the generated wastes are also increasing and consequently, the concentration of toxic. Numerical model solutions through plots and fitness of the model are presented and interpretation confesses the model as accurate. From results, we recommend that, waste management and limitation in contact of the population with the toxic are the ways to reduce their effects on human beings. To address the waste disposal and synthetic substances, the new trend of green chemistry with 12 principles is the alternative solution. Moreover, to reduce the increase of toxic waste, chlorine is replaced by carbonyl group and make it friendly to the environment, ecosystem and human.

Thomas Pettit, Peter J. Irga, Fraser R. Torpy

The ‘Black Summer’ wildfires that affected Australia over the 2019–2020 summer have led to concern over the health effects of exposure to wildfire emissions, and generated a need for means to reduce exposure. Recently, active green infrastructure has been implemented in cities to assist in the removal of urban air pollution, however the filtration of wildfire emissions has not been previously tested. Here, we field trial botanical biofiltration for the reduction of elevated air pollutant concentrations associated with Black Summer. Two active green walls were installed in outdoor environments in Sydney over Black Summer, with the concentrations of NO2, O3 and PM2.5 in ambient and filtered air streams monitored over 14 days with elevated air pollution concentrations due to wildfire emissions. Average pollutant single pass removal efficiencies of 63.17%, 38.79% and 24.84% for NO2, O3 and PM2.5 respectively were recorded, with clean air delivery rates of 558.90 m3/h, 343.19 m3/h and 219.77 m3/h for NO2, O3 and PM2.5 respectively for each 5 m2 biofilter wall. Weak negative associations were observed between the removal efficiency of NO2 and PM2.5 and their corresponding ambient concentrations. Strategic employment of botanical biofiltration may thus be of value in reducing wildfire emissions in sensitive populations.