Environmental Mitigation Strategies Research Articles

Developing onshore wind farms in Aotearoa New Zealand: carbon and energy footprints

ABSTRACT In recognition of deeper insights into the implications of wind farm deployments, this paper addresses the need for an updated Life Cycle Assessment (LCA) for onshore wind generation systems, using 4.3 MW wind turbines and direct drive permanent magnet synchronous generators. The environmental and energy performances were estimated through an LCA for an onshore wind plant under construction in Aotearoa New Zealand with a total nameplate capacity of 176 MW. This study used real construction data showing literature data overestimates civil works and underestimates transportation contributions in the wind farm footprint. Further, different end-of-life management alternatives for turbine blades are analysed: landfill, mechanical recycling, and chemical recycling. The results indicate a carbon footprint of 10.8–9.7 gCO2eq/kWh, a greenhouse gas payback time of 1.5–1.7 years for avoided combined cycle gas turbines, and an energy payback time of 0.4–0.5 years, in which the chemical recycling of the blades is the lower emission solution overall. The outcomes underscore the environmental efficiency of onshore wind farms and their important role in the energy transition. Notably, the manufacturing of wind turbines is the primary contributor to the carbon and energy footprints, highlighting a critical area for targeted environmental mitigation strategies.

Development of Electronic Packages with Integrated Environmental Mitigation

This paper demonstrates the techniques to integrate environmental protection into large format ceramic chip carriers using agile manufacturing techniques. Electronics packaging is critical for protecting integrated circuits and MEMS devices from austere environments. Typically, protecting packaged devices and circuit boards adds significant size to an assembly. Incorporating environmental mitigation strategies within the packages can reduce the total system size. In this effort, we developed a multi-faceted strategy to vibration, thermal, RF, and radiation interference with packaged chip. This effort included development of a thermomechanical isolation platform and RF shielding designs compatible with agile manufacturing methods (e.g., additive manufacturing). Shielding design evaluated materials to block external RF or radiation damage. Thermal isolation and vibration stress control was demonstrated using a suspended interposer. Lastly, ceramic demonstrator packages were printed using stereolithography, and were shown to survive high heat environments via heating with a 2000°C torch. Collectively, these results show that it is possible to provide environmental protection to essential chip and sensors within the package itself, reducing the volume needed for integration into flight systems. Furthermore, EngeniusMicro and partners have done so in using methodologies that allow for their production on-demand, both domestically and at the point-of-need.

Assessing Environmental Mitigation Strategies in Controlled Cage-Free Aviary Housing Systems: Effect on Air Quality and Bioaerosols

Highlights Three mitigation strategies were tested in experimental chambers fitted as small-scale aviaries. Particle monitor and high-flow air samplers were used to sample airborne dust (PM) and bioaerosols. Oil emulsion sprinkling on the litter surface of aviaries was effective in reducing PM emissions in experimental chambers. Abstract. Alternative housing systems for laying hens are gradually replacing battery cages. Though these systems provide more space per animal and enrichments, higher concentrations of ammonia and airborne dust have been reported in those environments. In this project, three environmental control strategies and a control condition were tested in twelve experimental chambers fitted as small-scale aviaries. The experiment was conducted during three periods spanning 18 weeks, during which PM and bioaerosols were sampled in each chamber in three separate sampling campaigns. Emissions of PM, culturable bacteria and molds, total bacteria, Penicillium, and Aspergillus molds and selected fecal indicators (Campylobacter coli, Campylobacter jejuni, Clostridium perfringens, Escherichia coli, Enterococcus spp., Salmonella spp.) were assessed in each experimental chamber. Strategies that included oil emulsion sprinkling on litter surface were effective at reducing PM emissions, while no significant effect (p > 0.05) was observed on ammonia emissions, and the effect on bioaerosol was variable under the evaluated conditions. Keywords: Airborne dust, Aviaries, Bioaerosol, Laying hen alternative housing, Mitigation.

Life cycle assessment of plastic packaging recycling embedded with responsibility distribution as driver for environmental mitigation

Life cycle assessment modelling of multi-cycle recycling systems is challenging. There is still neither consensus on applying allocation approaches nor a one-size-fits-all solution. This study proposes an allocation approach embedded with the responsibility distribution of stakeholders rather than the standard approach, which is assessed based on stages. It is applied to the case study of plastic packaging recycling and compared to simple and economic allocation cut-off methods. A total of four multiple recycling or cascade utilisation scenarios are assessed, consisting of the linear system (disposal), mechanical recycling, waste to energy and chemical recycling, for at least one of the cycles. Scenario 2, with mechanical recycling as the end-of-life management in all three multiple cycles, has the lowest overall GHG emissions (∼4.8 t CO2eq/t plastic packaging) regardless of allocation method, even after considering deducted savings due to the degraded quality along the cycles. The simple cut-off method could not drive the selection in the first cycle toward the recycling alternatives (Scenario 2–4) with overall lower emissions as the GHG saving from utilising recycled resources are accounted for in the second cycle. Regarding eutrophication potential, as the burdening impact of disposal is significantly higher, recycling options accounted for following the simple cut-off method are preferable even when the burdening effect is entirely embraced by the first cycle without the unburdening accounting. Economic allocation cut-offs provide a better incentive to recycle in the assessed cycles. However, the standard accounting is by stages such as material production, product manufacturing, recycling and disposal. It is unclear whose responsibility, either the raw material producer (MP), the product manufacturer (PM) or the consumer (C). The proposed method with defined responsibility (e.g. 6.2 t CO2eq/t by MP; 2.9 t CO2eq/t by PM; 0.5 t CO2eq/t by C in Scenario 1) is more effective for environmental mitigation strategies (e.g. taxation and incentives, deposit refund scheme) of the plastic life cycle. The scenarios assessment serves as a stepping stone to optimise the allocation among the identified stakeholders in future work according to local conditions.

Quantifying Environmental Mitigation of Aerosol Viral Load in a Controlled Chamber With Participants Diagnosed With Coronavirus Disease 2019.

BackgroundSeveral studies indicate that COVID-19 is primarily transmitted within indoor spaces. Therefore, environmental characterization of SARS-CoV-2 viral load with respect to human activity, building parameters, and environmental mitigation strategies is critical to combat disease transmission.MethodsWe recruited 11 participants diagnosed with COVID-19 to individually occupy a controlled chamber and conduct specified physical activities under a range of environmental conditions; we collected human and environmental samples over a period of three days for each participant.ResultsHere we show that increased viral load, measured by lower RNA cycle threshold (CT) values, in nasal samples is associated with higher viral loads in environmental aerosols and on surfaces captured in both the near field (1.2 m) and far field (3.5 m). We also found that aerosol viral load in far field is correlated with the number of particles within the range of 1 µm -2.5 µm. Furthermore, we found that increased ventilation and filtration significantly reduced aerosol and surface viral loads, while higher relative humidity resulted in lower aerosol and higher surface viral load, consistent with an increased rate of particle deposition at higher relative humidity. Data from near field aerosol trials with high expiratory activities suggest that respiratory particles of smaller sizes (0.3 µm -1 µm) best characterize the variance of near field aerosol viral load.ConclusionsOur findings indicate that building operation practices such as ventilation, filtration, and humidification substantially reduce the environmental aerosol viral load, and therefore inhalation dose, and should be prioritized to improve building health and safety.

Quantifying supply chain food loss in China with primary data: A large-scale, field-survey based analysis for staple food, vegetables, and fruits

Food loss has been widely identified as a key barrier to food security and environmental sustainability in developing countries. However, there remains a lack of empirical studies on the scales and patterns of food loss along the food supply chain in developing countries especially with updated and primary data. In this study, we aim to address this significant gap for China, based on a large-scale field study with questionnaire survey and qualitative interview of 1809 farmer households in 35 major agricultural producing counties of 12 provinces across China between April 2017 and September 2019. Three main agricultural products, staple food, vegetables, and fruits, and their entire supply chain from agricultural production to post-harvest handling, storage, processing, and distribution were covered. The normalized total losses of staple food, vegetables, and fruits added up to 7.9%, 27.7%, and 13.2%, respectively, of their total production. The major loss of staple food occurs at production stage, while post-harvest handling stage and distribution stage, respectively, contribute the most to vegetables and fruits losses. Although China's leapfrogging progress and technology development in recent years have resulted in a reduction of food loss, it was estimated that between 40% and 60% of these losses can still be further mitigated. Such primary data could improve our understanding on the scales and patterns of supply chain food losses in China and thus better inform food loss reduction interventions and associated economic and environmental mitigation strategies.

Seagrass contribution to blue carbon in a shallow karstic coastal area of the Gulf of Mexico.

Seagrass meadows provide multiple ecosystem services, including carbon sequestration. However, seagrass meadows are among the most threatened ecosystems worldwide. Determining the magnitude of the carbon stocks in seagrass meadows at the regional scale allows for the estimation of their global magnitude and identification of their importance in regional environmental mitigation strategies. The objective of the present study was to determine the structure of seagrass meadows in the Los Petenes Biosfera Reserve (LPBR) and evaluate their contributions to sinks of carbon in this system, located in Yucatan, which is considered the region with the largest seagrass extension in Mexico. Analyses of the seagrass meadows were executed following standardized protocols (spectral analysis, and isotope and carbon stock analyses). The LPBR stores an average of 2.2 ± 1.7 Mg C ha−1 in living biomass and 318 ± 215 Mg C ha−1 in sediment (top 1 m), and this carbon stock decreases with water depth. The seagrass community extends 149,613 ha, which represents the largest organic carbon stock (47 Tg C) documented in seagrass meadows in Mexico. Macroalgae and seagrass represent 76% of the organic carbon stored in sediment. If LPBR seagrass meadows are lost due to natural or anthropogenic impacts, 173 Tg CO2eqemissions could be released, which corresponds to the emissions generated by fossil fuel combustion of 27% of the current Mexican population. This information emphasizes the importance of seagrass meadows as a carbon sink in the region and their contribution to climate change mitigation, thus allowing for the implementation of necessary conservation strategies.

African Americans and European Americans exhibit distinct gene expression patterns across tissues and tumors associated with immunologic functions and environmental exposures

The COVID-19 pandemic has affected African American populations disproportionately with respect to prevalence, and mortality. Expression profiles represent snapshots of combined genetic, socio-environmental (including socioeconomic and environmental factors), and physiological effects on the molecular phenotype. As such, they have potential to improve biological understanding of differences among populations, and provide therapeutic biomarkers and environmental mitigation strategies. Here, we undertook a large-scale assessment of patterns of gene expression between African Americans and European Americans, mining RNA-Seq data from 25 non-diseased and diseased (tumor) tissue-types. We observed the widespread enrichment of pathways implicated in COVID-19 and integral to inflammation and reactive oxygen stress. Chemokine CCL3L3 expression is up-regulated in African Americans. GSTM1, encoding a glutathione S-transferase that metabolizes reactive oxygen species and xenobiotics, is upregulated. The little-studied F8A2 gene is up to 40-fold more highly expressed in African Americans; F8A2 encodes HAP40 protein, which mediates endosome movement, potentially altering the cellular response to SARS-CoV-2. African American expression signatures, superimposed on single cell-RNA reference data, reveal increased number or activity of esophageal glandular cells and lung ACE2-positive basal keratinocytes. Our findings establish basal prognostic signatures that can be used to refine approaches to minimize risk of severe infection and improve precision treatment of COVID-19 for African Americans. To enable dissection of causes of divergent molecular phenotypes, we advocate routine inclusion of metadata on genomic and socio-environmental factors for human RNA-sequencing studies.

Process-based LCA of ultrafiltration for drinking water production

Researchers and industrials need decision-making tools to make informed decisions on environmental mitigation strategies and proceed with the overall ecodesign of processes. In this study, a tool that couples membrane filtration process modelling and life cycle analysis has been developed, for which material and energy flows are calculated for variable operating conditions and are the basis for environmental impact assessment. The resulting generic model has been applied to dead-end ultrafiltration of ground and surface waters for drinking water production with cellulose triacetate hollow fibers. Operating strategies have been investigated to mitigate environmental impacts of the two major hotspots (electricity and backwash cleaning chemical consumptions). Adjusting filtration cycle duration and filtration flux has shown to be a promising lever. The developed model is sufficiently flexible and modular for its adaptation to other membrane materials, filtration configurations (i.e. cross-flow) as well as to other applications.

Environmental impact of personal protective equipment distributed for use by health and social care services in England in the first six months of the COVID-19 pandemic.

To quantify the environmental impact of personal protective equipment (PPE) distributed for use by the health and social care system to control the spread of SARS-CoV-2 in England, and model strategies for mitigating the environmental impact. Life cycle assessment was used to determine environmental impacts of PPE distributed to health and social care in England during the first six months of the COVID-19 pandemic. The base scenario assumed all products were single-use and disposed of via clinical waste. Scenario modelling was used to determine the effect of environmental mitigation strategies: (1) eliminating international travel during supply; (2) eliminating glove use; (3) reusing gowns and face shields; and (4) maximal recycling. Royal Sussex County Hospital, Brighton, UK. The carbon footprint of PPE distributed during the study period totalled 106,478 tonnes CO2e, with greatest contributions from gloves, aprons, face shields and Type IIR surgical masks. The estimated damage to human health was 239 DALYs (disability-adjusted life years), impact on ecosystems was 0.47 species.year (loss of local species per year), and impact on resource depletion was costed at US $12.7m (GBP £9.3m). Scenario modelling indicated UK manufacture would have reduced the carbon footprint by 12%, eliminating gloves by 45%, reusing gowns and gloves by 10% and maximal recycling by 35%. A combination of strategies may have reduced the carbon footprint by 75% compared with the base scenario, and saved an estimated 183 DALYS, 0.34 species.year and US $7.4m (GBP £5.4m) due to resource depletion. The environmental impact of PPE is large and could be reduced through domestic manufacture, rationalising glove use, using reusables where possible and optimising waste management.

Theory of Planned Behavior Environmental Management towards Environmental Behavior: A Mediating Effect of Islamic Knowledge and a Moderating Effect of Islamic Upbringing

This study conceptualizes a model of Islamic knowledge upbringings on university students' environmental behavior. This study extends the framework of the Theory of Planned Behavior by addressing multidisciplinary studies (Islamic study and environmental management). This study contributes to the environmental management literature by identifying the environmental management attitude, environmental management norms, and environmental management perceived behavioral control towards environmental management behavior. Besides, this study contributes to the theory by integrating the mediating effect of Islamic knowledge and a moderating effect of Islamic upbringing. The expected result of this study is that Islamic values improved environmental behavior, and Islamic upbringing has a big impact on the relationship between environmental management attitude, environmental management norms and, environmental management perceived control with environmental behavior. Thus, this study shows that even though societies understood the importance of taking care of the environment, moral values and family values are critical in shaping society's environmental behavior. This study helps the educational policymakers and the government policymakers to be able to implement better environmental mitigation strategies. This study also helps in promoting Islamic values in addressing environmental issues faces by this generation.

Environmental implications of the use of bio-cement treated recycled aggregate in concrete

Use of aggregates from recycled construction and demolition wastes in concretes alleviates the disposal problem and reduces the cost of concrete significantly. However, excessive water absorption, weak interfacial transition zone, and high porosity are its shortcomings. This study explores a bacterial cement and conventional cement slurry coating treatment on recycled coarse aggregates (RCA) for overcoming these shortcomings. In the first method, microbial carbonate precipitation (MCP) through bio-mineralization treatment has been utilized. Four different concretes were made using both control and treated aggregates. Once the performance of these concrete mixes was found adequate, a life cycle assessment was conducted using ISO14040–44 guideline to determine their environmental impacts. The experimental results confirmed that concrete with MCP treated aggregate offered better material performance than the untreated recycled aggregate based concrete mixes and possessed similar properties as natural aggregate concrete. While MCP process avoided the use of energy intensive cement, this research discovers that concrete with MCP treated aggregates was found to produce marginally higher environmental impacts than other concrete mixes mainly due to additional emissions associated with the bio-cement treatment of RCA. Further environmental mitigation strategies for concrete with MCP treated aggregates has considered to improve its environmental performance in terms of global warming impact and cumulative energy demand. This study demonstrates that the use of 100% RCA delivers significant environmental benefits in terms of ecological footprints, land conservation and biodiversity in a densely populated region like India.

Cost-effectiveness of environmental impact abatement measures in a European pig production system

Many emerging technologies and alternative farm management practices have the potential to improve the sustainability of pig production systems. The implementation of such practices is not always economically viable. The goal of this study was to assess the cost-effectiveness of such environmental mitigation strategies in pig systems, using an Environmental Abatement Cost analysis. We considered four pig housing (improved insulation, increased ventilation efficiency, frequent slurry removal, increased slurry dilution) and three manure management related abatement strategies (anaerobic digestion, slurry acidification, slurry separation), implemented as stand-alone and as a set of “pig housing–pig housing” and “pig housing–manure management” combinations. We calculated their annual equivalent value through a discounted cash flow analysis and then their annualised abatement potential through a cradle-to-farm gate life cycle assessment. The baseline system against which the analysis was conducted was a typical Danish pig production system, over a 25-year time horizon. The environmental impact categories considered were Non-Renewable Resource Use (NRRU), Non-Renewable Energy Use (NREU), Global Warming Potential (GWP), Acidification Potential (AP) and Eutrophication Potential (EP). Pig housing–anaerobic digestion combinations were the most cost-effective options for GWP, NRRU and NREU. Their abatement costs ranged from −€0.237 to €0.70 per tonne CO2 eq., −€0.146 to €0.36 per g Sb eq. and -€1.75−04 to €3.11−04 per GJ abated respectively. Anaerobic digestion was the most cost-effective stand-alone investment for GWP (−€0.206 per tonne CO2 eq.), NRRU (−€0.0493 per g Sb eq.) and NREU (−€1.00−04 per GJ), and slurry acidification for AP (€303 per tonne SO2− eq.) and EP (€1190 per tonne PO43− eq.) mitigation. Overall, measures for mitigation of GWP, NRRU and NREU required higher investments than for AP and EP, but also generated profit. The framework developed in this study can potentially aid decision making in the choice of environmentally and economically sustainable pig system modifications.

URBAN GEOMETRY MITIGATION GUIDELINES TO IMPROVE OUTDOOR THERMAL PERFORMANCE IN EGYPTIAN HOT ARID NEW CITIES

To keep up with world Rapid population growth in many countries including Egypt, the Egyptian government adopted polices to establish new urban communities, which many of them located in severe conditions of hot arid climate. However, the urban plans of those new cities do not prioritize the local climate considerations in its planning, which negatively effect on the thermal performance of urban spaces. In recent decades, greater attention was given to study the relationship between urban features and the local climate, developing mitigation and adaptation strategies with the aim of improving the thermal performance of urban spaces. So, this study aims to formulate a matrix of guidelines for urban heat islands mitigation strategies concerning urban geometry that can be helpful in improving the thermal performance of outdoor spaces in the existing new Egyptian cities -which allocated in hot arid climate zone, to enhance thermal comfort in these spaces.To achieve this goal, a comprehensive review, and analysis of the impacts of different urban geometrical thermal mitigation strategies on outdoor spaces in hot-arid climate, is presented. The geometrical variables of urban spaces which have been investigated in the reviewed researches classified into two main groups (squares and plazas, canyons). The geometrical variables of squares and plazas include; side compactness, and Sky View Factor (SVF). Canyons geometrical variables are; SVF, aspect ratio and side profile shape. These variables depend on the features of those spaces which resulting from the urban pattern form and geometry. These guided values have been applied theoretically and practically on three real cases, to illustrate the mechanism of matrix guidelines applying on urban outdoor spaces thermal behavior initial evaluation and determine the most suitable environmental mitigation strategies directly. Applying of guidelines help in mitigating thermal behavior of plaza with about 18.73 k degree and the canyon space with 3.28 k degree. The discussion of this research clearly reflects the importance of urban planning guidelines that can be applied to help enhancing outdoor thermal comfort. This study is useful in controlling the climatic consequences of urban planning at an early stage.

From the Building Level Energy Performance Assessment to the National Level: How are Uncertainties Handled in Building Stock Models

A considerable share of greenhouse gas (GHG) emissions is caused by the energy consumption for space heating and cooling in residential buildings. In Germany for instance about one third of the end energy consumption is accounted to space heating and cooling of buildings. Consequently, efforts to increase energy efficiency and substitute non-renewable energy with renewables are high. To explore the technical, economic and social effects of environmental mitigation strategies in order to increase energy efficiency in the building stock various models are used. Many of these models have to deal with the challenges of how to estimate energy demand levels. Derived from the recent development in this field researchers, planners and politicians are increasingly relying on energy models with integrated energy performance rating for environmental policy and strategy evaluation. However, energy assessments suffer from the common barriers of data access and data granularity. Therefore the approaches of energy building stock models comprise a mixture and variety of methods and have limits, which will be addressed in this contribution. The goal is to show how uncertainty is considered in existing models. This contribution provides general overview and key takeaways from the insight into different models and methodologies on the different levels of detail of building stock models.

Design of optimization model for a hydrogen supply chain under emission constraints - A case study of Germany

The increasing global demand for petroleum-based fuels, mainly driven by the economic growth in emerging markets imposes significant challenges in terms of energy supply and environmental mitigation strategies. This work introduces an approach for the design and decision making of primary energy source, production, storage, and distribution networks for hydrogen supply in regions (or countries) under emission constraints. The problem was mathematically represented using a source-sink system approach to determine the most suitable hydrogen supply chain (HSC) network. The optimization problem was formulated as a Mixed Integer Linear Programming (MILP) model using GAMS® modeling system. The optimization objective consists of the minimization of the total network cost, both in terms of capital and operating expenditures, subject to: supply, demand, mass conservation, technical performance, economic, and environmental constraints. The model was used to plan the future hydrogen supply chain network for Germany in the year 2030 under emission constraints. The optimization results show that the model is a valuable tool for planning the optimal hydrogen supply chain network of a particular region or country.

Temporal Variation of Wood Density and Carbon in Two Elevational Sites of Pinus cooperi in Relation to Climate Response in Northern Mexico

Forest ecosystems play an important role in the global carbon cycle. Therefore, understanding the dynamics of carbon uptake in forest ecosystems is much needed. Pinus cooperi is a widely distributed species in the Sierra Madre Occidental in northern Mexico and future climatic variations could impact these ecosystems. Here, we analyze the variations of trunk carbon in two populations of P. cooperi situated at different elevational gradients, combining dendrochronological techniques and allometry. Carbon sequestration (50% biomass) was estimated from a specific allometric equation for this species based on: (i) variation of intra-annual wood density and (ii) diameter reconstruction. The results show that the population at a higher elevation had greater wood density, basal area, and hence, carbon accumulation. This finding can be explained by an ecological response of trees to adverse weather conditions, which would cause a change in the cellular structure affecting the within-ring wood density profile. The influence of variations in climate on the maximum density of chronologies showed a positive correlation with precipitation and the Multivariate El Niño Southern Oscillation Index during the winter season, and a negative correlation with maximum temperature during the spring season. Monitoring previous conditions to growth is crucial due to the increased vulnerability to extreme climatic variations on higher elevational sites. We concluded that temporal variability of wood density contributes to a better understanding of environmental historical changes and forest carbon dynamics in Northern Mexico, representing a significant improvement over previous studies on carbon sequestration. Assuming a uniform density according to tree age is incorrect, so this method can be used for environmental mitigation strategies, such as for managing P. cooperi, a dominant species of great ecological amplitude and widely used in forest industries.

Large Omnivore Movements in Response to Surface Mining and Mine Reclamation

Increasing global demands have resulted in widespread proliferation of resource extraction. Scientists are challenged to develop environmental mitigation strategies that meet societal expectations of resource supply, while achieving minimal disruption to sensitive “wilderness” species. We used GPS collar data from a 9-year study on grizzly bears (Ursus arctos) (n = 18) in Alberta, Canada to assess movements and associated space use during versus after mining. Grizzly bear home range overlap with mined areas was lower during active mining except for females with cubs, that also had shortest movements on active mines. However, both females with cubs and males made shorter steps when on/close to mines following mine closure and reclamation. Our results show differences in bear movement and space-use strategies, with individuals from a key population segment (females with cubs) appearing most adaptable to mining disturbance. Preserving patches of original habitat, reclaiming the landscape and minimizing the risk of direct human-induced mortality during and after development can help conserve bears and other wildlife on industrially modified landscapes.

Source characterization of organic aerosols using Monte Carlo source apportionment of PAHs at two South Asian receptor sites

Abstract The quantification of source contributions is of key importance for proposing environmental mitigation strategies for particulate organic matter. Organic molecular tracer analysis of polycyclic aromatic hydrocarbons (PAHs) and n -alkanes was conducted on a set of winter samples from two regional receptor sites in South Asia: the Island of Hanimaadhoo (the Republic of Maldives) and a mountain top near Sinhagad (W. India). Monte Carlo source apportionment (MCSA) techniques were applied to the observed PAH ratios using profiles of a representative range of regional combustion sources from the literature to estimate the relative source contributions from petroleum combustion, coal combustion and biomass burning. One advantage of this methodology is the combined use of the mean and standard deviation of the diagnostic ratios to calculate probability distribution functions for the fractional contributions from petroleum, coal and biomass combustion. The results of this strategy indicate a higher input from coal combustion at the Hanimaadhoo site (32–43 ± 21%) than the Sinhagad site (24–25 ± 18%). The estimated biomass contribution for Sinhagad (53 ± 22%) parallels previous radiocarbon-based source apportionment of elemental carbon at this location (54 ± 3%). In Hanimaadhoo, the MCSA results indicate 34 ± 20% biomass burning contribution compared to 41 ± 5% by radiocarbon apportionment of EC. While the MCSA based on PAH ratio diagnostic distributions are less precise than the radiocarbon-based apportionment, it provides additional information of the relative contribution of two subgroups, coal and petroleum combustion, within the overall contribution from fossil fuel combustion.

The impact of potential nitrous oxide mitigation strategies on the environmental and economic performance of dairy systems in four New Zealand catchments

The expansion of the New Zealand dairy industry has resulted in growing concern about the environmental impacts. As such, efforts are being made to design environmentally and economically sustainable management strategies. In this desktop study, the performance of two management strategies was assessed for dairy systems in four New Zealand catchments. Survey and monitoring information on farm management, farm production, and soils was used to estimate nitrous oxide (N2O) and total greenhouse gas (GHG, i.e. N2O, methane and carbon dioxide) emissions, nitrate leaching and profitability of farms under current management, and of farms using wintering pads and nitrification inhibitors. Under the wintering pad option, it was estimated that N2O emissions decreased by up to 8%, total GHG emissions increased by up to 10%, and nitrate leaching losses decreased by up to 44%. In terms of economic performance, wintering pads slightly decreased farm Earnings Before Interest and Tax (EBIT) on three of the four catchments. On the other hand, the use of a nitrification inhibitor has the potential to reduce N2O emissions, total GHG emissions and nitrate leaching losses from all catchment case study farms while increasing the EBIT. This study suggested that nitrification inhibitors can be a cost-effective mitigation strategy for reducing dairy farm N emissions to air and water. The analysis also illustrated the importance of assessing environmental mitigation strategies at a farm-systems level, including relevant off-farm activities.