Journal of the Air & Waste Management Association最新文献

As the air permitting process evolves, so have environmental justice (EJ) considerations. Amidst several states' EJ-specificinitiatives, Colorado's Air Pollution Control Division (APCD) has become a national leader in addressing EJ concerns through the stationary source permitting process. Colorado began this process by publishing internal Division guidance that required longer public comment periods and other enhanced public outreach for certain stationary source permitting actions. Today, Colorado has enacted new laws and regulations, including the Environmental Justice Act and Air Quality Regulation Number 3 that aim to address harmful air quality disparities by requiring Environmental Justice Summaries, enhancedmodeling, and source-specific monitoring, among other measures. APCD has worked with several partners to establish a robust data set from which state permitting authorities can identify certain permit applications for facilities that are advised to conduct more extensive public engagement; a case study of enhanced engagement is included in this paper.Implications: Environmental Justice (EJ) in air permitting requires ongoing adaptation to regulatory frameworks, data availability, and community engagement. The Division has integrated EJ considerations into permitting through the implementation of EJ Summaries, enhanced modeling, and source-specific monitoring. However, significant challenges remain, including data limitations, the complexity of regulatory compliance, ensuring meaningful community participation, and addressing historic socioeconomic disparities. The Division is committed to refining its approach by improving data transparency, enhancing communication with affected communities, and integrating lessons learned from other state agencies. Revisions to Regulation 3 reflect a broader strategy to incorporate EJ principles into permitting decisions while maintaining regulatory clarity. The Division engages in local dialogue to ensure that impacted communities understand regulatory requirements and how to effectively participate in public comment opportunities. These conversations inform the Division's decision-making processes and help refine policies that mitigate health and environmental disparities.

Odor is a serious issue for municipal solid waste treatment process, and chemical absorption is a common technology for odor control. Interactions among odorants will influence the performance of chemical absorption, and they are still not fully understood. This work took the common and important odorants, including hydrogen sulfide (H₂S), methanethiol, propanethiol and acetaldehyde, as examples, to investigate the removal performance of mixed odorants by sodium hypochlorite (NaClO) solution at different concentrations, and interactions among the odorants. The absorption experiments were conducted in gas-washing bottles with single or mixture of H₂S, methanethiol, propanethiol and acetaldehyde as the inlet gases, and NaClO solutions at different concentrations as the absorption solutions. The thermodynamic equilibrium was simulated. Acetaldehyde was eliminated mainly by physical absorption, and the removal efficiency was not affected by the other three odorants. The removal efficiencies of H₂S, methanethiol, and propanethiol increased with the chlorine concentration ([Cl₂]), and reached nearly 100% by the NaClO solution of pH = 12.19, [Cl₂] = 158.00 mg/L. H₂S, methanethiol, and propanethiol competed for reacting with NaClO. H₂S was more effectively removed than methanethiol and propanethiol due to its lower pKa value. The removal efficiency of methanethiol decreased linearly with the increase in methanethiol and H₂S concentrations mainly due to the consumption of NaClO. Propanethiol removal was decreased by both methanethiol and H₂S, and methanethiol had more influence than H₂S due to the higher consumption of NaClO. The odor control performance could be overestimated when there are several important odorants, and only the removal efficiency of a single odorant was considered. Correspondingly, suggestions for chemical scrubber operation were provided, including the consideration of odorant interactions, the selection of monitoring odorants, and the optimization of operating parameters (pH and [Cl₂]) using machine learning methods.Implications: Chemical absorption is widely applied for odor control, and the interaction between odorants is an important influencing factor of the performance. Hydrogen sulfide, methanethiol, propanethiol and acetaldehyde are common and important odorants emitted during municipal solid waste treatment. This work investigated the removal performance of chemical absorption for the single and mixture of these odorants, and revealed the interaction between them, as well as the risk of overestimating odor performance with the removal efficiency of a single odorant, which can provide insights into optimizing odor control technologies.

Residential wood combustion is an important source of heat for millions of households, yet it represents the third largest source of PM_2.5 pollution in the United States. Development of cleaner-burning cordwood heating stove designs is necessary to reduce health and climate impacts from this important renewable energy source. Effective design requires an understanding of operation and performance of existing stoves in real-world settings. In this study, one uncertified stove, three EPA Phase I or II stoves, and three New Source Performance Standards (NSPS) stoves were sampled for 48 consecutive hours each in households in rural Oregon. The methodology included stack sampling of undiluted CO and CO₂ with a diluted sample train for cooling and condensation of PM and an optical sensor to apportion integrated gravimetric measurements of particle mass over time. A data-logging scale directly measured fuel loading mass and timing, enabling emissions mass calculations via both stack flow and carbon balance methods. Results across all stoves showed that together cold starts and reloads contribute 70% of total PM emissions. The measured period emission rate of PM over all stoves was 5.6 ± 2.2 g/hr, while the average emission factor of PM was 8.5 ± 3.0 g/kg. There was a statistically significant reduction of between 29.6-48.5% in the PM emission rate during all periods except burnout and a 40.6 increase in thermal efficiency of the NSPS stoves relative to the single uncertified stove during the fire period. Implications of this study include both a database of in-field emissions and efficiency performance measures and comparison of stove certification levels that are useful to wood stove designers and policymakers for optimizing air quality impacts of stove-user systems. In addition, the methods demonstrated here can be used by researchers to promote needed field monitoring capabilities at a lower cost and complexity.Implications: Detailed time-apportioned PM emissions data identified conditions leading to high emission rates including startup, large loads, and operation of an uncertified stove. Provides wood stove designers insights toward optimizing performance of future stove designs, and policy makers information about the impact of user and technology on air quality objectives. Demonstrated new equipment for real-time emissions and fuel consumption monitoring that enables time-resolved PM and direct fuel mass measurements to yield better design insights for heating stoves. This method can be used by other researchers to gather much needed field measurements at a lower cost and complexity than existing methods.

Video imaging spectro-radiometry (VISR) has been proposed as a means to quantify the combustion efficiency (CE) of flares. This work presents a numerical assessment of VISR using computational fluid dynamics simulations of a steam-assisted industrial flare, with a focus on three aspects: how approximations in the spectroscopic model impact the local "pixel-wise" CE, the validity of the approach for computing flare global CE using inferred local CE values, and the ability and limitations of VISR instrument to capture fuel that may be aerodynamically stripped from the combustion zone under crosswind conditions. The present analysis is conducted using simulated images generated over bands aligned with absorption features of three key products of flare combustion: CO₂ (4.2-4.4 µm), CO (4.5-4.9 µm), and CH₄ (3.2-3.4 µm). The results show that the simplified VISR approach can predict local CE accurately, but the instrument model used to convert these values into a flare global CE potentially leads to large biases. Finally, since the technique relies on mid-infrared imaging, it is likely incapable of quantifying unburned (cold) methane that may be stripped from the combustion zone due to the presence of a high crosswind over the flare stack, leading to a significant overestimation of the actual flare performance.Implications: Oil and gas producers and regulators increasingly rely on continuous monitoring emission systems to measure methane slip, e.g., under OGMP 2.0. However, the effectiveness of many of these techniques, particularly those based on spectroscopic principles, has yet to be established in a rigorous way, particularly given the uncertainties inherent in extractive monitoring. This paper presents a methodology that focuses on one emerging continuous monitoring technology and could be adapted as a general strategy for benchmarking the performance of continuous monitoring systems.

Solid waste has become one of the critical problems of today's cities due to rapid population growth and uncontrolled urbanization. In urban waste management, waste bins are placed inefficiently and collection routes are often determined manually. This situation increases operating costs and causes some environmental and sociological problems. In this study, a web-based Geographic Information Systems (GIS) application was developed that optimizes the locations of waste bins and determines the routes to transfer waste from these bins to transfer stations or disposal facilities for urban waste management. For the developed Web-GIS application, some scripts were designed in Python language that use real-time population data to optimize the locations of waste bins. ArcGIS Network Analyst Vehicle Routing Problems (VRP) tool was also used to determine the routes. The developed application aims to improve the efficiency of waste collection operations by optimizing bin placement and reducing travel distance. The developed application was tested in a region of the Ortahisar district in Trabzon/Türkiye where different scenarios can be evaluated. According to the results of the pilot region study, travel distance improved by 12.4% and operation time improved by approximately 44.58% compared to the current situation. It is evaluated that these improvements will also reduce carbon emissions and waste management costs. Additionally, this application can be scaled and adapted for use in other urban areas facing similar waste management challenges.Implications: The Solid Waste Management System (SWMS) has been developed to accurately collect and dispose of waste, addressing the mentioned problems. The SWMS offers the benefit of automating all activities from waste collection to disposal. This study aims to create a web-based application for SWMS to identify the most suitable locations for waste bins and routes to transfer solid waste from these bins to transfer stations or disposal facilities. As a result of the studies, it was determined that significant improvements could be made in route length, collection time and workforce, and that waste bins could be placed more efficiently.

Residential wood heating (RWH) is a known source of particulate matter (PM), hazardous air pollutants (HAPs), and greenhouse gases (GHGs). However, the influence of operating conditions on emissions from certified cordwood stoves in the United States (U.S.) remains poorly understood. This study analyzes emissions data from different operational phases, including start-up, high heat, and low heat, to improve indicators of real-world stove performance. We tested five commercially available U.S. stoves through the four distinct operational conditions or phases of the novel Integrated Duty Cycle (IDC) testing protocol, which simulates typical residential wood-burning patterns by incorporating start-up, high heat, medium (or "maintain") heat, and low heat ("overnight" burn) phases. We determined emissions factors (EFs) by IDC phase for criteria, GHG, and HAP compounds, including volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs). We also developed a multiple linear regression model to assess the effect of dry burn rate (DBR) and IDC phase on each pollutant EF by stove technology type. IDC phase significantly influenced (p < 0.01) pollutant EFs from uncertified stoves and most emissions from catalytic/hybrid stoves, while DBR played a more substantial role in emissions from non-catalytic stoves. Current stove certification methods rely on a single nominal load under steady-state combustion, which does not reflect typical residential use. Additionally, we found DBR to be an inconsistent predictor of emissions in cordwood stoves. These findings underscore the importance of stove technology and operating conditions in determining RWH emissions, with implications for air quality science and regulatory policy.Implications: We report cordwood stove emissions factors by operating condition using the novel Integrated Duty Cycle (IDC) protocol on various U.S. technologies meeting 2020 New Source Performance Standards (NSPS) and one pre-NSPS, circa 1980 stove. We determined significant effects from IDC operating phase on uncertified and catalytic/hybrid stove emissions, but not noncatalytic stoves. This has important implications for use of emissions factors in air quality science, policy, and stove design, as different U.S. climate zones will influence the number of stove start-ups, fuel loading patterns, and frequencies of other "real world" operating conditions such as "high heat" and "overnight burn."

Electrostatic precipitation (ESP) is a technology widely used to remove particulate matter (PM) from industrial gas streams. To adopt the same for varying scales as well as for different clean air delivery applications as in indoor and outdoor air pollution, there exists a requirement for the development of comprehensive, readily adaptable, reasonably good, comparable, rigorous, step-by-step analytical theory and experimental validation of same for design of modular units of ESP. In this regard, the current study conducted theoretical and experimental studies to investigate corona characterization and PM collection efficiency in a modular unit of a single-wire, single-stage, wire-plate ESP with square cross-sectional geometry. The best agreement between the I-V characteristics of theory and the experiment was obtained while adjusting the inception electric field to 12.35 × 10⁵ Vm^-1 as well as the ion diffusion coefficient value to to 0.0647 × 10^-4 m²s^-1. Tuned theory predicted PM collection efficiency at three different flow rates of 30, 50, and 100 LPM and at various potentials 9, 11, and 13 kV, respectively. Comparing the predicted results from theory and experiment, it is understood that agreement between theory and experiment is acceptable in the case of varied flow rates and is good for potentials for varied size ranges from 13 nm to 800 nm. As accuracy and reliability of present model are verified in terms of collecting efficiency at different operating conditions of flow rate as well as potential, present model can facilitate the design and scale-up of ESPs for indoor PM control with high collection efficiency. The study also illustrated a sample calculation on the applicability of this filter-less technology for air cleaning in an indoor environment.Implications: Although corona modelling is a classical subject with much work already available, only a few studies focus on single-stage ESP where charging and collection happen simultaneously. In this regard, a comprehensive, readily adaptable, reasonably good, comparable, rigorous, step-by-step analytical theory that integrates particle charging and collection was developed. Different experiments were performed to validate the model. Comparing the predicted results from theory and experiment, it is understood that agreement between theory and experiment is acceptable in the case of varied flow rates and is good for potentials for varied size ranges from PM sizes 13 nm to 800 nm.

Mega-sporting events like the Olympics and FIFA World Cup generate immense waste, mirroring unsustainable global production and consumption patterns. Effective waste management strategies are crucial, given volumes reaching tens of thousands of tons during these temporary, high-intensity events. This review paper investigates the evolution of waste policies and technological interventions across major sporting events over the past two decades. Waste volumes, compositions, management approaches, and environmental impacts were assessed through systematic literature analysis. Findings reveal waste generation from 0.25 to over 7 kg per spectator daily, with food, paper, plastics, packaging, and construction debris being predominant components. A transition from fragmented coordination toward integrated national sustainability strategies demonstrates growing prioritization of event waste concerns. Recent editions emphasize circular economy principles like reduction, reuse, recycling, and recovery, yet challenges persist in translating ambitions into actions. While technological solutions, including waste-to-energy, smart monitoring, and data analytics, show promise, systemic change requires multi-pronged efforts. Key recommendations encompass proactive, integrated planning across all event stages, continuous innovation, behavior change through education campaigns and incentives, coordinated policy interventions between sporting bodies and government agencies, and strengthened cross-sector collaboration spanning vendors, builders, technology providers, environmental groups, and local communities. With strategic leadership, the influential sports industry could revolutionize circular production and consumption systems globally by embracing sustainability as a core ethos.Implications: This research underscores the significant environmental challenges posed by waste generated during mega-sporting events and highlights the evolving strategies to address these issues. Policymakers can leverage these insights to develop integrated, sustainable waste management practices that align with circular economy principles. By promoting proactive planning, technological innovation, and cross-sector collaboration, governments and sporting bodies can mitigate the environmental impact of these events. The study's findings advocate for coordinated policy interventions and behavioral change initiatives, emphasizing the need for a systemic shift toward sustainability. This research not only informs future event planning but also contributes to broader efforts in advancing global sustainability agendas.