Abatement Strategies Research Articles

Sustainable Wastewater Treatment Strategies in Effective Abatement of Emerging Pollutants

The fundamental existence of any living organism necessitates the availability of pure and safe water. The ever-increasing population has led to extensive industrialization and urbanization, which have subsequently escalated micropollutants and water contamination. The environmental impact on various life forms poses a dire need for research in effective environmental management. Versatile technologies involving multiple approaches, including physiochemical and biological bioremediation strategies, draw insights from environmental biology. Metabolic annihilation mediated by microbes shows significant potential in the bioconversion of toxic micropollutants to tolerable limits. Environmentally friendly, cost-effective, and sustainable strategies are envisaged for efficient environmental protection. Phytoremediation technology, especially floating wetland treatments, facilitates micropollutant elimination, landscape management, ecosystem conservation, and aesthetic enhancement in diverse environments. The incorporation of nanomaterials in the bioremediation of toxic micropollutants augments novel and innovative strategies for water pollution abatement. This paper offers a novel strategy that combines nanomaterials to improve micropollutant degradation with bioremediation techniques, particularly the creative application of phytoremediation technologies like floating wetlands. Combining these techniques offers a novel viewpoint on long-term, affordable approaches to reducing water pollution. Additionally, the review proposes a forward-looking strategic framework that addresses the accumulation and refractory nature of micropollutants, which has not been thoroughly explored in previous literature.

Soundscape Architecture: conceptual proposals for improving the urban soundscape through building in Fort Lauderdale, FL

Architecture students from the University of Florida School of Architecture developing architectural and planning strategies in response to citizen generated initiative to improve the soundscape at multiple locations in Fort Lauderdale Florida. Site analysis including citizen participation in sound walks, personal observations, photo documentation, precedent studies, acoustic measurements, geographical measurements, and municipal code studies was conducted. This information informed conceptual and schematic design proposals for urban architecture (buildings), at critical locations in the urban fabric that seek to provide strategies toward improving the soundscape while supporting high residential density, mixed-use, entertainment, and transit. The work includes 11 student project proposals spanning two academic semesters. The work illustrates integrated design proposals addressing aspects of urban soundscapes such as: vertical distance as effective sound abatement strategy; buildings as acoustic buffers from transit or noisy streets; building envelope systems that both limit sound transmission and absorb sound; sound diffusing buildings; parking or limited occupancy program as buffer spaces; and land development code adoptions that can facilitate future implementation of effective soundscape improvement strategies. This paper will demonstrate the design process, issues of concern, prioritization of issues per specific sites, and show illustrations to visualize a range of soundscape strategies as architecture.

A framework for the acoustic simulation of passing vehicles using variable length delay lines

The sound produced by vehicles driving on roadways constitutes one of the dominant noise sources in urban areas. The impact of traffic noise on human activities and the related investigation on modeling, assessment, and abatement strategies fueled the research on the simulation of the sound produced by individual passing vehicles. Simulators enable in fact to promote a perceptual assessment of the nature of traffic noise and of the impact of single road agents on the overall soundscape. In this work, we present TrafficSoundSim, an open-source framework for the acoustic simulation of vehicles transiting on a road. We first discuss the generation of the sound signal produced by a vehicle, represented as a combination of road/tire interaction noise and engine noise. We then introduce a propagation model based on the use of variable length delay lines, allowing to simulate acoustic propagation and Doppler effect. The proposed simulator incorporates the effect of air absorption and ground reflection, modeled via complex-valued reflection coefficients dependent on the road surface impedance, as well as a model of the directivity of sound sources representing the passing vehicles. The source signal generation and the propagation stages are decoupled, and all effects are implemented using finite impulse response filters. Moreover, no recorded data is required to run the simulation, making the framework flexible and independent on data availability. Finally, to validate the framework capability to accurately simulate passing vehicles, a comparison between synthetic and recorded pass-by events is presented. The validation shows that sounds generated with the proposed method achieve a good match with recorded events in terms of power spectral density and psychoacoustics metrics as well as a perceptually plausible result.

Interrogation of a fluoropolymer dispersion manufactured with a non-fluorinated polymerization aid for targeted and non-targeted fluorinated residuals by liquid chromatography high resolution mass spectrometry

Recent advances in fluoropolymer polymerization have focused on replacing perfluorinated polymerization aids (PAs) with hydrocarbon-based alternatives. Hydrocarbon PAs are vulnerable to fluorinated radicals during polymerization, leading to the creation of hundreds of process-specific polyfluorinated residuals. These residuals, which include low molecular weight extractable or leachable impurities, are challenging to detect at trace levels. This study investigates a polytetrafluoroethylene (PTFE) dispersion prepared with a hydrocarbon-based surfactant (DOSS) to measure these process-specific fluorinated residues. Liquid chromatography high resolution mass spectrometry is one of the few analytical methods that offers the sensitivity and selectivity required to detect these residuals in complex matrices at concentrations as low as parts per billion. The results indicate that using a hydrocarbon PA during emulsion polymerization produces numerous polyfluorinated residuals. These must be identified and monitored to develop effective abatement strategies, ensuring responsible fluoropolymer manufacturing.

Unveiling heavy metal pollution dynamics in sediments of river Ulhas, Maharashtra, India: a comprehensive analysis of anthropogenic influence, pollution indices, and health risk assessment.

Metals and metalloids tainting sediments is an eminent issue, predominantly in megacities like Mumbai and Navi Mumbai, requiring an exhaustive examination to identify metal levels in river bodies that serve various populations. Thus, utilising pollution indices, multivariate analysis, and health risk assessment studies, we propose a novel investigation to examine the metal content in the Ulhas River sediments, a prominent agricultural and drinking water supply (320 million-litre per day) near Mumbai in Maharashtra, India. The eleven metals and metalloids (As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, and Zn) were examined monthly from 10 stations totaling 120 sediment specimens from October 2022 to September 2023. Investigations revealed that average values of Cr, Cu, Hg, and Ni exceeded Australian and New Zealand Environment and Conservation Council and Agriculture and Resource Management Council values, while all metals exceeded World surface rock average limits except As. Various pollution indices showed that upstream sites had noneto low levelcontamination, whereas downstream locations had moderate to considerablecontamination, suggesting anthropogenic influences. Furthermore, multivariate analysis including correlation, cluster, and principal component analysis identified that sediment pollution was mostly caused by anthropogenic activities. Lastly, health risk assessment indicated Fe was non-carcinogenic to children, whereas Cr and Ni were carcinogenic to children and adults, with children being more susceptible. Thus, from the findings of the study it is clear that, despite low to moderate pollution levels, metals may have significant repercussions, thus requiring long-term planning, frequent monitoring, and metal abatement strategies to mitigate river contamination.

Health equity and synergistic abatement strategies of carbon dioxide and air pollutant emissions reduction in China’s eastern coastal area

Abstract Quantifying regional health disparities linked to air pollution is essential for enhancing air quality and attaining carbon neutrality objectives. Nonetheless, the efficacy of proactive policies in ensuring equitable health protection in China’s Eastern Coastal Area (ECA) remains uncertain. Here, we employed an integrated assessment model to assess the combined reduction of carbon dioxide (CO2) and atmospheric pollutants and their health repercussions in the ECA of China. Our findings reveal that 273 000 premature deaths are attributable to air pollution in 2060 in the ECA in the absence of mitigation policies. Conversely, carbon reduction policies are poised to curtail 80% of CO2 emissions, alongside reductions of 76% for NOx, 79% for SO2, 80% for PM2.5, 72% for VOCs, and 66% for NH3 emissions. Air pollution control policies could mitigate premature deaths by 19 600, while carbon reduction policies could potentially lower them by 50 800. The health inequality coefficient among provinces stands at 0.19, primarily attributable to significantly higher mortality rates in Hebei and Shandong. These findings yield valuable insights for crafting synergistic abatement strategies in similarly imbalanced developmental regions grappling with comparable environmental challenges.

Balancing greenwashing risks and forest carbon sequestration benefits: A simulation model linking formal and voluntary carbon markets

Voluntary carbon markets (VCMs) offer energy-intensive firms a cost-effective means to reduce carbon mitigation expenses through promoting forest conservation. However, concerns about greenwashing may deter firms from using these options, which are susceptible to illegal forest harvesting. This study examines whether firms purchasing carbon credits from forestry-based communities can help strengthen forest conservation, mitigate project risks, improve environmental outcomes, and reduce abatement costs. We examine a large Indian steel firm, with an annual production capacity of 4 million tons, issuing green bonds to fund afforestation in Himalayan forest communities. Using industry-level average emissions, abatement costs, and output data for Indian firms, we develop a dynamic optimization model to determine optimal abatement strategies, considering the risk of future forest carbon loss from VCMs. The model, utilizing examples and data from existing carbon sequestration programs in the Himalayan states, offers insights into promoting high-integrity VCMs through formal emission market linkage. Findings suggest that firms' involvement in compliance emissions markets provides an alternative route to accessing affordable carbon credits when abatement costs are high. Additionally, engaging in the VCM reduces expenses related to emission reduction targets. However, with elevated greenwashing risks, firms reduce their use of green bonds in VCMs. Participation in the VCM positively reinforces forest conservation and enhances environmental services when greenwashing risks are absent, further lowering carbon mitigation costs. To enhance VCM integrity, further research is needed on how community conservation norms influence illegal harvesting.

Development of new framework for order abatement and control design strategy

Development of new framework for order abatement and control design strategy

Impact of manganese mining on potentially toxic elements pollution and bioaccumulation in Spirogyra varians and Hydrilla verticillata in the Xiaojiang River.

Potentially toxic elements (PTEs) pose a significant threat to aquatic ecosystems. This study investigated the content and potential sources of PTEs (Cr, Mn, Ni, Cu, Zn, Cd, Pb) in water, sediment, and dominant aquatic plants (Hydrilla verticillata and Spirogyra varians) in the Xiaojiang River, located near the Zhaiying manganese mine in Guizhou Province, China. Correlation analysis, principal component analysis (PCA), and cluster analysis were employed to assess PTE distribution and potential sources. Water PTE concentrations complied with the Class II standard (GB3838-2002), indicating no water pollution. However, sediment PTE levels exceeded background values, particularly Mn, which exhibited moderate to strong contamination. Cd also showed moderate contamination, posing a considerable ecological risk. Cd was the main potential pollutant with the highest contribution rate. Mn and Cd were therefore identified as priority pollutants requiring targeted abatement strategies. Mining activities likely represent the primary source, but combined pollution from vehicle traffic and agriculture might also contribute. Hydrilla verticillata demonstrated a higher capacity for PTE enrichment from sediment compared to Spirogyra varians, suggesting its potential for sediment remediation (except for Cu). A significant correlation existed between both plant species and sediment PTE content. PCA supported the association between S. varians and sediment PTEs. Linear regression analyses revealed better correlations between S. varians and sediment Mn, Ni, Cu, and Zn (0.77, 0.68, 0.82, and 0.79, respectively). Taken together, these findings suggest that S. varians serves as an effective bioindicator for monitoring sediment contamination with PTEs.

Host-feeding preferences and temperature shape the dynamics of West Nile virus: A mathematical model to predict the impacts of vector-host interactions and vector management on [formula omitted]

West Nile virus (WNV) is prevalent across the United States, but its transmission patterns and spatio-temporal intensity vary significantly, particularly in the Eastern United States. For instance, Chicago has long been a hotspot for WNV cases due to its high cumulative incidence of infection, with the number of cases varying considerably from year to year. The abilities of host species to maintain and disseminate WNV, along with eco-epidemiological factors that influence vector-host contact rates underlie WNV transmission potential. There is growing evidence that several vectors exhibit strong feeding preferences towards different host communities. In our research study, we construct a process based weather driven ordinary differential equation (ODE) model to understand the impact of one vector species (Culex pipiens), its preferred avian and non-preferred human hosts on the basic reproduction number (R0). In developing this WNV transmission model, we account for the feeding index, which is defined as the relative preference of the vectors for taking blood meals from a competent avian host versus a non-competent mammalian host. We also include continuous introduction of infected agents into the model during the simulations as the introduction of WNV is not a single event phenomenon. We derive an analytic form of R0 to predict the conditions under which there will be an outbreak of WNV and the relationship between the feeding index and the efficacy of adulticide is highly nonlinear. In our mechanistic model, we also demonstrate that adulticide treatments produced significant reductions in the Culex pipiens population. Sensitivity analysis demonstrates that feeding index and rate of introduction of infected agents are two important factors beside the efficacy of adulticide. We validate our model by comparing simulations to surveillance data collected for the Culex pipiens complex in Cook County, Illinois, USA. Our results reveal that the interaction between the feeding index and mosquito abatement strategy is intricate, especially considering the fluctuating temperature conditions. This induces heterogeneous transmission patterns that need to be incorporated when modelling multi-host, multi-vector transmission models.

The Relationship of Surface Ozone Pollution with Meteorological Conditions in Determining Episode Periods

Jakarta, the capital city of Indonesia, is located in a tropical region with abundant sunlight and high temperatures year-round. Ozone and particulate matter (PM) are critical parameters causing unhealthy air pollution. Meteorological data were obtained from the NASA Power website. This study aims to explore the relationship between ozone formation and meteorological factors in Jakarta. Ozone air quality data were measured using the Backman model 950A ozone Analyzer, which detects concentrations as low as 0.05 ppm, with measurements taken every 40 seconds. From January to October 2023, ozone concentrations increased during the dry months of May to October, with the highest hourly value recorded at 263 μg/m³. During this period, average temperatures ranged from 27-29°C, rainfall was 0.3-5.6 mm, wind speeds were 3.14-4.64 m/s, wind direction was 92-171 degrees, and air humidity was 74-82%. Significant episodes were identified on (i) May 5-9, (ii) July 12-15, (iii) September 6-7, (iv) September 13-14, (v) September 21-22, and (vi) October 29-30, 2023. Daily, monthly, and seasonal ozone variations aligned with meteorological conditions, showing higher concentrations during the dry months. Further studies, including photochemical modeling, are required to identify dominant factors causing high ozone concentrations during these episodes. Understanding NOx or VOC emission sensitivities is crucial for effective ozone abatement strategies in Jakarta.

Transformation and Mitigation of Tar and Related Secondary Pollutants during Sewage Sludge Pyrolysis

Sewage sludge has long been perceived as the bottleneck of wastewater treatment plants in China, restraining the healthy development of sewage treatment for decades. In recent years, pyrolysis as a promising multifunctional platform has attracted increasing interest for converting sludge into valuable resources. However, the generation and presence of pyrolysis tar, one of the key by-products during sludge pyrolysis, limit the wide application of pyrolysis product resources. The efficient and selective conversion of tar is complicated by the inherent complexity of sludge and various pollutants (e.g., N-, S-, and Cl-containing organic pollutants, heavy metals) in pyrolysis products, which may either migrate into tar or be released into the environment, complicating the in-depth treatment of tar and posing environmental risks. This review systematically examines the transformation and migration of tar and related secondary pollutants during sludge pyrolysis in order to optimize the pyrolysis process for resource recovery. We provide an overview of the research progress on tar generation, transformation, and secondary pollutants during pyrolysis; discuss potential control strategies for pollution abatement; and highlight the importance of understanding tar transformation during pyrolysis. Additionally, we offer insights into future development trends and research hotpots in this field. This review aims to deliver valuable information on the mechanism of tar formation, the conversion pathways of secondary pollutants, and corresponding control strategies, thus guiding the design and optimization of sludge pyrolysis processes to achieve higher efficiency and selectivity, with minimal environmental pollution.

Road traffic noise pollution and prevalence of ischemic heart disease: modelling potential association and abatement strategies in noise-exposed areas.

In many developing countries with surging vehicular traffic and inadequate traffic management, excessive road traffic noise exposure poses substantial health concerns, linked to increased stress, insomnia and other metabolic disorders. This study aims to assess the linkage between sociodemographic factors, traffic noise levels in residential areas and health effects using a cross-sectional study analyzing respondents' perceptions and reports. Noise levels were measured at 57 locations in Srinagar, India, using noise level meter. Sound PLAN software was employed to generate noise contour maps, enabling the visualization of noise monitoring locations and facilitating the assessment of noise levels along routes in proximity to residential areas. Correlation analysis showed a strong linear relationship between field-measured and modelled noise (r2 = 0.88). Further, a questionnaire-based survey was carried out near the sampling points to evaluate the association of ischemic heart disease with traffic noise. Residents exposed to noise levels (Lden > 60dB(A)) were found to have a 2.24 times higher odds ratio. Compared to females, males reported a 16% higher prevalence of the disease. Multi-faceted policy strategies involving noise mapping initiatives, source noise standards, traffic flow urban mobility optimization, smart city initiatives and stringent litigatory measures could significantly reduce its detrimental impact on public health. Finally, this study envisions a region-specific strong regulatory framework for integrating noise pollution mitigation strategies into the public health action plans of developing nations.

Dynamic modeling of the moisture and salt's transport in the unearthed terracotta warriors of emperor Qin's mausoleum museum, China

Terracotta figurines excavated from archaeological sites frequently exhibit salt damage due to moisture-salt transport. Understanding this dynamic within the terracotta figurines and soil system is essential for accurately predicting salt damage and implementing well-informed, timely preventative measures. While moisture-salt transport in the soils of historical sites is well-documented, the numerical modeling of this process is rare, specifically within the Terracotta figurines-soil coupled system. In the present work, a numerical model focused on the Terracotta figurine-soil system at Emperor Qin's Mausoleum Museum (China) was established, which employed the variable saturation Richards flow equation and the Fickian advection-diffusion equation. The model was validated using soil column experiments. The results showed that the semi-buried figurines were more susceptible to salt damage, with uneven salt distribution primarily due to moisture-salt transport at the interface. After the excavation, the first month was identified as a critical period for rapid migration of moisture and salt, representing the highest risk of damage. These insights offer a framework for estimating the risk of salt damage over time, underpinning the development of future abatement strategies. This study not only advances the understanding of salt damage in Terracotta figurines but also lays the groundwork for safeguarding these archaeological treasures.

Assessment of light-absorbing carbonaceous aerosol origins and properties at the ATOLL site in northern France

Abstract. Understanding the lifecycle of light-absorbing carbonaceous aerosols, from emission to deposition, is critical for assessing their climate impact. This study integrated multi-year aerosol observations from the ATOLL (ATmospheric Observations in liLLe, northern France) platform, with air mass back trajectories and emission inventory as a newly developed “INTERPLAY” (IN-siTu obsERvations, hysPLit, And emission inventorY) approach. Applied to black carbon (BC), the method apportioned source contributions (shipping, vehicular, residential heating, industrial) and studied aerosol aging effects, notably on the brown carbon (BrC) component. Results estimate that, throughout the year, vehicular traffic dominated BC (31 %), followed by shipping (25 %, of which one-third was from canals/rivers) and residential heating (21 %). Comparing INTERPLAY results with the aethalometer model highlights that the “residential sector” BC can be entirely apportioned to BC from wood burning (BCwb), notably in winter, while vehicular traffic corresponds to only about 41 % of BC fossil fuel (BCff) at the ATOLL site, the rest being apportioned to shipping (33 %) and industrial (23 %) emissions. Thus, vehicular traffic and BCff should not be used interchangeably, particularly in regions near intense maritime traffic. Concerning BrC, our analysis confirms a dominant role of residential heating. Focusing on winter, results suggest a considerable decrease in the BrC component only 24 h after emission, with fresh residential emissions being responsible for 72 % of BrC absorption at ATOLL. The results from this study allow for an improved understanding of sources and atmospheric dynamics of light-absorbing carbonaceous aerosols in northern France, being crucial for both source abatement strategies as well as a better assessment of their climate impact.

Spatially and Temporally Differentiated NOx and VOCs Emission Abatement Could Effectively Gain O3-Related Health Benefits.

The increasing level of O3 pollution in China significantly exacerbates the long-term O3 health damage, and an optimized health-oriented strategy for NOx and VOCs emission abatement is needed. Here, we developed an integrated evaluation and optimization system for the O3 control strategy by merging a response surface model for the O3-related mortality and an optimization module. Applying this system to the Yangtze River Delta (YRD), we evaluated driving factors for mortality changes from 2013 to 2017, quantified spatial and temporal O3-related mortality responses to precursor emission abatement, and optimized a health-oriented control strategy. Results indicate that insufficient NOx emission abatement combined with deficient VOCs control from 2013 to 2017 aggravated O3-related mortality, particularly during spring and autumn. Northern YRD should promote VOCs control due to higher VOC-limited characteristics, whereas fastening NOx emission abatement is more favorable in southern YRD. Moreover, promotion of NOx mitigation in late spring and summer and facilitating VOCs control in spring and autumn could further reduce O3-related mortality by nearly 10% compared to the control strategy without seasonal differences. These findings highlight that a spatially and temporally differentiated NOx and VOCs emission control strategy could gain more O3-related health benefits, offering valuable insights to regions with severe ozone pollution all over the world.

Dissolved Organic Matter-Mediated Photosensitized Activation of Monochloramine for Micropollutant Abatement in Wastewater Effluent.

Utilizing solar light and water matrix components in situ to reduce the chemical and energy demands would make treatment technologies more sustainable for micropollutant abatement in wastewater effluents. We herein propose a new strategy for micropollutant abatement through dissolved organic matter (DOM)-mediated photosensitized activation of monochloramine (NH2Cl). Exposing the chlorinated wastewater effluent with residual NH2Cl to solar irradiation (solar/DOM/NH2Cl process) degrades six structurally diverse micropollutants at rate constants 1.26-34.2 times of those by the solar photolysis of the dechlorinated effluent (solar/DOM process). Notably, among the six micropollutants, the degradation rate constants of estradiol, acetaminophen, bisphenol A, and atenolol by the solar/DOM/NH2Cl process are 1.13-4.32 times the summation of those by the solar/DOM and solar/NH2Cl processes. The synergism in micropollutant degradation is attributed to the generation of reactive nitrogen species (RNS) and hydroxyl radicals (HO·) from the photosensitized activation of NH2Cl. Triplet state-excited DOM (3DOM*) dominates the activation of NH2Cl, leading to the generation of RNS, while HO· is produced from the interactions between RNS and other photochemically produced reactive intermediates (e.g., O2·- and DOM·+/·-). The findings advance the knowledge of DOM-mediated photosensitization and offer a sustainable method for micropollutant abatement in wastewater effluents containing residual NH2Cl.

Techno-economic assessment of biopolymer production from methane and volatile fatty acids: effect of the reactor size and biomass concentration on the poly(3-hydroxybutyrate-co-3-hydroxyvalerate) selling price

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) is a biobased and biodegradable polymer that could efficiently replace fossil-based plastics. However, its widespread deployment is slowed down by the high production cost. In this work, the techno-economic assessment of the process for producing poly(3-hydroxybutyrate-co-3-hydroxyvalerate) from low-cost substrates, such as methane and valeric acid derived from the anaerobic digestion of organic wastes, is proposed. Several strategies for cost abatement, such as the use of a mixed consortium and a line for reagent recycling during downstream, were adopted. Different scenarios in terms of production, from 100 to 100,000 t/y, were analysed, and, for each case, the effect of the reactor volume (small, medium and large size) on the selling price was assessed. In addition, the effect of biomass concentration was also considered. Results show that the selling price of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) is minimum for a production plant with 100,000 t/y capacity, accounting for 18.4 €/kg, and highly influenced by the biomass concentration since it can be reduced up to 8.6 €/kg by increasing the total suspended solids from 5 to 30 g/L, This adjustment aligns the breakeven point of PHBV with the reported average commercial price.

Enhanced atmospheric oxidation toward carbon neutrality reduces methane’s climate forcing

The hydroxyl radical (OH), as the central atmospheric oxidant, controls the removal rates of methane, a powerful greenhouse gas. It is being suggested that OH levels would decrease with reductions of nitrogen oxides and ozone levels by climate polices, but this remains unsettled. Here, we show that driven by the carbon neutrality pledge, the global-mean OH concentration, derived from multiple chemistry-climate model simulations, is projected to be significantly increasing with a trend of 0.071‒0.16% per year during 2015–2100. The leading cause of this OH enhancement is dramatic decreases in carbon monoxide and methane concentrations, which together reduce OH sinks. The OH increase shortens methane’s lifetime by 0.19‒1.1 years across models and subsequently diminishes methane’s radiative forcing. If following a largely unmitigated scenario, the global OH exhibits a significant decrease that would exacerbate methane’s radiative forcing. Thus, we highlight that targeted emission abatement strategies for sustained oxidation capacity can benefit climate change mitigation in the Anthropocene.

Trade liberalization and the choice of pollution abatement

AbstractIt is well known that a consumer price-neutral reform of consumption taxes and import tariffs is welfare-improving. This paper shows that such price controls are inferior to quantity controls in terms of welfare improvement. The paper next turns to a comparison of different abatement strategies. Whether or not policy changes should fix private abatement or public abatement relates to the level of earmarking, and depends on the relationship between private production and public abatement. There are cases in which increased public abatement only improves welfare by more than both increased private and public abatement together. The paper recommends that environmental earmarking in the form of public abatement should be delivered to cushion price hikes and sustain private energy consumption.