Journal of the Air & Waste Management Association最新文献

Fine particulate matter (PM_2.5) is hypothesized to induce oxidative stress, and has been linked to acute and chronic adverse health effects. To better understand the risks and underlying mechanisms following exposure, PM_2.5 is collected onto filters but prior to toxicological analysis, particles must be removed from filters. There is no standard method for filter extraction, which creates the possibility that the methods of extraction selected can alter the chemical composition and ultimately the biological implications. In this study, comparisons were made between extraction solvents (methanol (MeOH), dichloromethane (DCM), 0.9% saline, and Milli-Q water) and the results of oxidative potential and elemental concentration analysis of PM_2.5 collected across sites in Arkansas, USA. Significant differences were observed between solvents, with DCM having significantly different results compared to all other extraction solvents (p ≤ 0.001). Significant correlations between element, black carbon, and PM_2.5 concentrations and oxidative potential were observed. The observed correlations were extraction solvent dependent. For example, in saline extracted samples, oxidative potential had significant negative correlations with: Ba, Cd, Ce, Co, Ga, Mn and significant positive correlations with: Cr, Ni, Th, U. While in MeOH extracted samples, significant positive correlations were only between oxidative potential and Ga, U and significant negative correlations with V. This indicates that PM_2.5 samples extracted with different solvents will yield different conclusions about the causal components. This study highlights the importance of filter extraction methods in interpretation of oxidative potential results and comparisons between studies.Implications: While there is no standard method for PM_2.5 filter extraction, variation of extraction methods impact analytical results. This project identifies that extraction method variation, particularly extraction solvent selection, leads to discrepancies in chemical and toxicological analysis for PM_2.5 collected on the same filter. This work highlights the need for methods standardization to support accurate comparisons between PM_2.5 research studies, thus providing better understanding of PM_2.5 across the globe.

This study focused on the feasibility of identifying and recycling inorganic phase-change materials (PCMs) from sugar industry wastes in two cities of Qazvin and Hamadan in Iran. In this study, dry sugar beet pomace, sugar beet pomace, sugar beet molasses, leaves and plant residues of sugar beet and sugarcane bagasse were investigated. The inorganic materials were identified by X-ray Diffraction (XRD), thermal characteristics were determined by differential scanning calorimetry (DSC), and morphological characteristics were determined by scanning electron microscopy (SEM). Additionally, physical and thermal properties of molasses and bagasse samples were analyzed to determine their suitability as inorganic PCMs. The results of this study demonstrated that molasses and bagasse have the potential to be used as mineral PCMs in thermal energy storage applications. The results of this study demonstrated that in the wet sugar beet pomace the highest and lowest concentrations of inorganic PCMs were silicon dioxide (SiO₂) and sodium chloride (NaCl), respectively. Moreover, the highest calcium fluoride (CaF₂) composition was reported in dry sugar beet pomace. In the samples of leaves and residues of sugar beet and sugarcane bagasse, the highest concentration of was NaCl. The detection and recycling of mineral PCMs from sugar industry wastes offer a sustainable solution for waste management and provide a renewable source of thermal energy storage materials.Implications: This study demonstrated the potential for the extraction of inorganic phase-change materials from sugar industry wastes as a means of solid waste management. By repurposing these materials, we can reduce the environmental impact of sugar production and contribute to sustainable practices in the industry.

A variety of sources of pollutant emissions can be represented as area sources. These include manure lagoons, landfills, wastewater treatment ponds, and highways. A group of point sources can also be treated as an area source. The impact of an area source is usually computed by representing the area source as a set of line sources perpendicular to the wind direction. As for point sources, the Gaussian horizontal concentration distribution used to compute the contributions of the line sources is likely to overestimate ground-level concentrations when the wind speed is comparable to the standard deviation of the horizontal velocity fluctuations. A variety of methods are used to mitigate this overestimation under these conditions, referred to as meander. As an example of one these approaches, we examine that of AERMOD, EPA's regulatory model. AERMOD includes meander in modeling the impact of point and volume sources, but has not yet incorporated it into AERMOD's area source algorithm. This paper describes an approach to include meander in AERMOD's area source algorithm and demonstrates its impact on concentrations associated with area sources.Implications: Inclusion of wind direction meander in modeling dispersion when the wind speed is low is important in ensuring that AERMOD does not overestimate concentrations under these conditions. In view of the importance of area sources of pollution, the results presented in this paper represent a potential enhancement of AERMOD's ability to estimate the upper end of the concentration distribution, which forms the basis of the regulatory acceptance of the model.

Over the past decades, the amount of waste has dramatically increased worldwide due to rapid population growth and urbanization. Inefficient waste collection and transportation, known as the waste collection vehicle routing problem (WCVRP), negatively impacts economic, environmental, and social dimensions. This issue has drawn considerable attention from local and national governments. There is an urgent need for sustainable practices in waste collection and transportation. This paper conducts an exhaustive literature review on the WCVRP. The review covers various aspects, including waste types, common model characteristics, objective functions, solution methods, datasets and case studies. The analysis indicates a need for further research on underrepresented waste types, such as medical waste (MW). It also stresses the importance of incorporating more model characteristics to better capture the complexities of real-world scenarios. Moreover, there is a lack of multiple objectives optimization models that concurrently address economic, environmental, and social dimensions, in line with sustainable development goals. Additionally, there is insufficient research on hybrid algorithms, especially regarding their application to uncertainty management and advanced techniques. Finally, the use of hybrid testing is restricted, highlighting the need for diverse tests to validate solution methods under various real-world conditions. This study outlines a roadmap for decision-makers in the WCVRP domain, offering opportunities for the evolution of more efficient, adaptable, and sustainable waste collection and transportation systems.Implications: The discussion of WCVRP is an urgent global concern in waste management that requires immediate attention. Through a multi-dimensional evaluation of the research papers, this review paper provides recommendations for future research and practice in WCVRP. Initially, while urban solid waste has received significant attention, other categories remain insufficiently examined. Future research should focus on efficient collection and transportation strategies for these types. Then, although common characteristics are well-explored, this review emphasizes the need for further investigation into lesser-studied characteristics and vehicle types in WCVRP models. Next, current models predominantly prioritize cost and public health exposure risk minimization. There is a necessity for more holistic approaches that incorporate multiple objectives, particularly those crucial for achieving sustainable development goals. Moreover, hybrid algorithms have emerged as efficient solutions, yet advanced technologies coupled with uncertainty management strategies remain underutilized, presenting significant potential to address the evolving complexities of WCVRP. Finally, the study highlights the importance of datasets and case studies in validating WCVRP models. Hybrid tests enable researchers to comprehensively evaluate WCV

In addition to selective catalytic reduction (SCR) and selective non-catalytic reduction (SNCR) which are available to remove NO_x from flue gas, oxidation method is receiving more and more attention because this method makes it possible to remove NO_x and SO₂ from flue gas simultaneously by wet scrubbing. O₃ as a strong oxidant has a high oxidation capacity and it can oxide NO to N₂O₅ which has a higher water solubility compared with NO₂. However, it needs a long reaction time and the escape of unreacted ozone may cause secondary pollution. In this study, FeMnCo/Al₂O₃ catalyst and FeMnCe/Al₂O₃ catalyst were prepared and applied to enhance the deep oxidation of NO_x with ozone and reduce O₃ slip. Effects of various operating parameters such as O₃/NO ratio, gas residence time, and operating temperature were evaluated, and the results demonstrate that N₂O₅ began to generate when O₃/NO ratio was higher than 1.0 and increased with increasing O₃/NO ratio. Little residual O₃ was formed in the presence of catalyst, while 350 ppm O₃ was measured at the outlet gas when O₃/NO ratio was controlled at 2.0. The N₂O₅ conversion efficiency increased with increasing gas residence time and operating temperature, and the highest N₂O₅ conversion efficiency was achieved at 100°C. Furthermore, the conversion efficiency remained around 90% during 20 h operation over FeMnCe/Al₂O₃ catalyst with an O₃/NO ratio of 1.73, a gas residence time of 1.2 s, and a temperature of 100°C. On the other hand, the N₂O₅ conversion efficiency remained around 80% during 3 h operation over FeMnCo/Al₂O₃ catalyst. Overall, FeMnCe/Al₂O₃ catalyst reveals good potential for deep oxidation of NO by O₃ and can be further developed as a viable catalyst for reducing NO emission from industries.Implications: In this study, FeMnCo/Al₂O₃ catalyst and FeMnCe/Al₂O₃ catalyst were applied to enhance the deep oxidation of NO into N₂O₅ with O₃. The catalysts can improve the conversion of NO into N₂O₅, shorten the reaction time and reduce the unreacted O₃ slip, which are beneficial to reduce the size of the reactor required and cost of APCDs (air pollution control devices) in practical application. This method can make it possible to simultaneously remove NO_x and SO₂ from flue gas by wet scrubbing for reducing NO emissions from industries, especially small and medium scaled industries, to meet increasingly stringent emission standards.

Respiratory infections are currently understood to be caused by pathogens released through the nose or mouth of an infected individual, and subsequently transmitted to susceptible hosts. These pathogens are enclosed in liquid particles that are aerosolized from the respiratory tract during activities such as breathing, speaking, sneezing, and coughing. These particles vary widely in size, ranging from submicron to several microns. While past research has largely overlooked the human respiratory system, recent analysis has revealed that the actual structure of the nasal cavity significantly influences the prediction of aerosol transmission during exhalation. In this study, computational fluid dynamics (CFD) simulations were conducted to analyze the aerosol transmission generated during exhalation from the nasal and oral cavities. Realistic nasal and oral cavity structures were taken into account, and authentic temperature distributions were applied to the surfaces. Additionally, inhalation conditions for susceptible individuals were established to evaluate the risk of inhalation-generated exposure. Through various simulation scenarios, we separately discussed the impact of environmental wind speed, separation distance, and exhalation flow rate. The simulation results indicate that environmental wind amplifies the complexity of the flow field and the transmission and deposition of particles between two individuals. Under ambient wind velocities of 0.5 m/s and 1 m/s, it was observed that over 80% of the particles with a diameter of 1 µm inhaled through the nasal cavity accounted for the total deposition on the infected individual. Furthermore, high exhalation flow rates exhibited higher deposition ratios at close distances, in line with our expectations. Therefore, it is advisable to minimize close contact as much as possible during periods of frequent respiratory infections, and to wear masks in order to reduce the risk of inhalation exposure.Implications: During the activities such as breathing, speaking, sneezing, and coughing, liquid particles containing pathogens are aerosolized from the respiratory tract and are released from nose or mouth through the nebulization. In this study, we investigated the transmission of aerosols from human exhalation in the outdoor environment, innovatively taking the real oral-nasal structure and the active inhalation of vulnerable people into consideration, and explored the human-to-human transmission of respiratory viruses. The results are beneficial for public health assessment and policy development.

Airborne radioactivity from fossil fuel production systems is poorly characterized, but a recent study showed elevated ambient levels with proximity to oil and gas production wells. Here, we report year-long, high temporal resolution monitoring results of airborne alpha radioactivity from both radon gas and radon progeny attached to particulates immediately northeast of an oil refinery in Commerce City, Colorado, USA, in an environmental justice community of concern. Gas and particle-associated radioactivity contributed nearly evenly to the total alpha radioactivity. Total radioactivity levels of 30-40 Bq m^-3 were 2-3 times higher than background levels (~10-15 Bq m^-3) when winds were light and southwesterly, suggesting the refinery as the geographic origin. Furthermore, elevated airborne radioactivity tracked most closely with the light hydrocarbon and natural gas tracer ethane. Thus, the data imply natural gas as the radon emission carrier. Our findings are unique and suggest a need for further investigations of radon emissions from oil and gas infrastructure such as natural gas processing plants, compressor stations, petrochemical plants, and oil refineries that process oil and natural gas from unconventional production.Implications: Regulatory agencies currently do not mandate or conduct monitoring of radioactivity releases and public exposure from petroleum industry air emissions. This study reports elevated radioactivity from radon gas and nonvolatile radon decay products attached to particulate matter, at about 2-3 times above background levels in proximity to Colorado's largest oil refinery. Observations were within an environmental justice community of concern that experiences well above-average exposure to many other harmful atmospheric pollutants, suggesting potential adverse health effects from this cumulative exposure. Our findings offer actionable insights for policymakers, industry stakeholders, and affected communities alike.

During the utilization, blending, transportation, and storage, a significant amount of volatile organic compounds (VOCs) are released from inks, posing risks to both human health and the ecological environment. This study sought to identify the types and structures of VOCs released from four types of solvent-based inks (referred to as CAB, PVB, AKR, and Rs inks) in high-temperature settings and to assess the bioaccumulation factors, developmental toxicity, and acute toxicity of these released VOCs. The findings revealed that all tested inks released substantial amounts of VOCs in high-temperature environments. CAB and PVB inks released fewer types of VOCs with relatively smaller molecular weights, primarily with carboxylic acid groups and hydroxyl groups, while AKR and Rs inks released more types of VOCs with larger molecular weights, including polycyclic aromatic hydrocarbons. Toxicity analysis indicated that although the primary VOCs released from CAB and PVB ink displayed some developmental toxicity, their bioaccumulation factors were below 100. The principal VOCs from AKR ink did not exhibit developmental toxicity. Conversely, the predominant VOCs from Rs ink not only demonstrated developmental toxicity but also had bioaccumulation factors exceeding 100. Additionally, the VOCs released from CAB, PVB, and AKR inks exhibited stronger acute toxicity to luminescent bacteria, while those from Rs ink showed greater acute toxicity to fish. These results offer a scientific foundation for the safe usage of inks and environmental conservation.Implications: This study provides critical insights into the types and toxicity of volatile organic compounds (VOCs) emitted from solvent-based inks under high-temperature conditions. The findings have significant implications for environmental policy and industrial practices. The identification of VOCs, particularly from CAB, PVB, AKR, and Rs inks, and their associated health and ecological risks, can inform regulatory bodies about the need for stricter emission controls. The assessment of bioaccumulation factors and acute toxicity highlights the potential for these compounds to accumulate in organisms and impact aquatic life, necessitating the development of safer ink formulations and disposal methods. Policymakers can leverage these results to update environmental regulations, promote the use of eco-friendly inks, and encourage technological advancements in the printing industry to minimize VOC emissions. Additionally, the study underscores the importance of continued research in this area to further understand the long-term effects of VOCs on human health and the environment, ultimately guiding more sustainable and responsible industrial practices.