Synthesis and review: tackling the nitrogen management challenge: from global to local scales

One of the 'grand challenges' of this age is the anthropogenic impact exerted on the nitrogen cycle. Issues of concern range from an excess of fixed nitrogen resulting in environmental pressures for some regions, while for other regions insufficient fixed nitrogen affects food security and may lead to health risks. To address these issues, nitrogen needs to be managed in an integrated fashion, at a variety of scales (from global to local). Such management has to be based on a thorough understanding of the sources of reactive nitrogen released into the environment, its deposition and effects. This requires a comprehensive assessment of the key drivers of changes in the nitrogen cycle both spatially, at the field, regional and global scale and over time. In this focus issue, we address the challenges of managing reactive nitrogen in the context of food production and its impacts on human and ecosystem health. In addition, we discuss the scope for and design of management approaches in regions with too much and too little nitrogen. This focus issue includes several contributions from authors who participated at the N2013 conference in Kampala in November 2013, where delegates compiled and agreed upon the 'Kampala Statement-for-Action on Reactive Nitrogen in Africa and Globally'. These contributions further underline scientifically the claims of the 'Kampala Statement', that simultaneously reducing pollution and increasing nitrogen available in the food system, by improved nitrogen management offers win-wins for environment, health and food security in both developing and developed economies. The specific messages conveyed in the Kampala Statement focus on improving nitrogen management (I), including the reduction of nitrogen losses from agriculture, industry, transport and energy sectors, as well as improving waste treatment and informing individuals and institutions (II). Highlighting the need for innovation and increased awareness among stakeholders (III) and the identification of policy and technology solutions to tackle global nitrogen management issues (IV), this will enable countries to fulfil their regional and global commitments

The Emission Inventory System for Upper Austria: The Role of Environmental Information Systems in Translating Complex Information to a User s Requirements

Advances in environmental sciences increase the difficulty in creating products that can be readily used by non-experts. In this paper we demonstrate how a carefully designed environmental system is able to provide solutions. While complex transformations are kept in the system background, predefined expert choices give a user great flexibility in selecting what is required for the specific applications. In the given case study, emissions of atmospheric pollutants in the province of Upper Austria can not only be calculated for a multitude of options, but a scenario tool also allows for deep modifications of the models, if required. The example demonstrates how environmental experts and computer science experts have to work hand-in-hand to translate model treatment of environmental processes into a user-friendly environment. The overall system is also characterized in its theoretical framework. Seen as a deterministic model, an increasing amount of data input and better understanding of the underlying processes will allow a more realistic simulation of the reality. Without a full validation, however, just increasing the model size will not improve performance. Instead, an expert system will be built, which is overdetermined with respect to input quality, but contains the best available expert judgement on the processes described. Such an expert system should not be expected to possess any predictive qualities outside of the range of the test data. Consequently data reduction has to take place both in terms of model complexity and in terms of the required input. This kind of data reduction requires implicit expert knowledge, model reductions are the essence of any explicit process description

Nitrogen in Current European Policies

Europe, and especially the European Union (EU), has many governmental policy ¿ measures aimed at decreasing unwanted reactivenitrogen (N r ) emissions from combustion, agriculture and urban wastes. Many of these policy measures have an ¿eff ects-basedapproach¿, and focus on single N r compounds, single sectors and either on air or waters.¿ Th is chapter addresses the origin, objectives and targets of EU policy measures related to Nr emissions, considers which instrumentsare being used to implement the policies and briefl y discusses the eff ects of the policy measures.Approaches¿ Th e chapter starts with a brief description of the basic elements of governmental policy measures.¿ A review of the main international conventions and EU policies related to emissions of Nr to air and water is then provided.¿ Finally the chapter provides a semi-quantitative assessment of the eff ectiveness and effi ciency of European policy measures.Key fi ndings/state of knowledge¿ International conventions and other treaties have played a key role in raising awareness and establishing policy measures for Nr emissionsabatement in EU through so-called Directives and Regulations.¿ Th ere are many diff erent EU Directives, oft en addressing individual Nr compounds from individual sectors (e.g. NOx emissions fromcombustion; NH 3 emissions from agriculture, pollution of groundwater and surface water by nitrates from agriculture, discharge oftotal nitrogen from urban sewage to surface waters).¿ Many EU Directives have been revised following review and evaluation. Th ere are increasing eff orts to cluster single EU Directives intolarger Framework Directives.¿ Compliance with, and eff ectiveness of, the Directives diff ers between sectors; it decreases in the order (i) reducing NO x emissions fromcombustion sources, (ii) reducing nitrogen (and especially Phosphorus) discharges to waters from industries and households, and (iii)reducing NH 3 emissions and NO 3 leaching from agriculture.¿ Th ere is not much literature on the diff erences in the eff ectiveness and effi ciencies of Directives; a number of factors seem to be involvedin eff ectiveness and effi ciency, but these have not yet been analysed in a coherent manner.Major uncertainties/challenges¿ Th ere is a huge diversity in N r emission sources and pathways, while the number of policy instruments is limited. Th ere is need to fi ndthe optimal mix of policy instruments targeted to the emission sources as well as the stakeholders involved.¿ It has been indicated that some EU Directives addressing emissions of nitrogen compounds from specifi c sources have antagonisticeff ects. Th e magnitude of these eff ects is not yet well known.¿ Th ere is a delay in the environmental and ecological responses following the introduction of Directives; these are due to legislativedelays, lack of enforcement and control, constraints in practice and because of biogeochemical hysteresis eff ects; these eff ects are notyet well understood quantitatively.¿ In general, only modest reductions in Nr emissions from agriculture have been achieved to date; this refl ects the need for more eff ectiveand effi cient policy measures and/or greater enforcement of current policies.Recommendations¿ To examine further the diff erences between sectors of the factors that contribute to the eff ectiveness and effi ciency of policy measuresfor the abatement of N r emissions.¿ T o explore further the eff ectiveness and effi ciency of more integrated N management and integrated policy measures for the abatementof adverse impacts of N r emissions.JRC.DDG.H.2-Climate change and air qualit

Evaluating the potential of dietary crude protein manipulation in reducing ammonia emissions from cattle and pig manure: A meta-analysis

Dietary manipulation of animal diets by reducing crude protein (CP) intake is a strategic NH3 abatement option as it reduces the overall nitrogen input at the very beginning of the manure management chain. This study presents a comprehensive meta-analysis of scientific literature on NH3 reductions following a reduction of CP in cattle and pig diets. Results indicate higher mean NH3 reductions of 17 ± 6% per %-point CP reduction for cattle as compared to 11 ± 6% for pigs. Variability in NH3 emission reduction estimates reported for different manure management stages and pig categories did not indicate a significant influence. Statistically significant relationships exist between CP reduction, NH3 emissions and total ammoniacal nitrogen content in manure for both pigs and cattle, with cattle revealing higher NH3 reductions and a clearer trend in relationships. This is attributed to the greater attention given to feed optimization in pigs relative to cattle and also due to the specific physiology of ruminants to efficiently recycle nitrogen in situations of low protein intake. The higher NH3 reductions in cattle highlights the opportunity to extend concepts of feed optimization from pigs and poultry to cattle production systems to further reduce NH3 emissions from livestock manure. The results presented help to accurately quantify the effects of NH3 abatement following reduced CP levels in animal diets distinguishing between animal types and other physiological factors. This is useful in the development of emission factors associated with reduced CP as an NH3 abatement option. © 2017, The Author(s)

Evaluating the potential of dietary crude protein manipulation in reducing ammonia emissions from cattle and pig manure: A meta-analysis

Dietary manipulation of animal diets by reducing crude protein (CP) intake is a strategic NH3 abatement option as it reduces the overall nitrogen input at the very beginning of the manure management chain. This study presents a comprehensive meta-analysis of scientific literature on NH3 reductions following a reduction of CP in cattle and pig diets. Results indicate higher mean NH3 reductions of 17 ± 6% per %-point CP reduction for cattle as compared to 11 ± 6% for pigs. Variability in NH3 emission reduction estimates reported for different manure management stages and pig categories did not indicate a significant influence. Statistically significant relationships exist between CP reduction, NH3 emissions and total ammoniacal nitrogen content in manure for both pigs and cattle, with cattle revealing higher NH3 reductions and a clearer trend in relationships. This is attributed to the greater attention given to feed optimization in pigs relative to cattle and also due to the specific physiology of ruminants to efficiently recycle nitrogen in situations of low protein intake. The higher NH3 reductions in cattle highlights the opportunity to extend concepts of feed optimization from pigs and poultry to cattle production systems to further reduce NH3 emissions from livestock manure. The results presented help to accurately quantify the effects of NH3 abatement following reduced CP levels in animal diets distinguishing between animal types and other physiological factors. This is useful in the development of emission factors associated with reduced CP as an NH3 abatement option. © 2017, The Author(s)

An intercomparison of measurement systems for vapor and particulate phase concentrations of formic and acetic acids

During June 1986, eight systems for measuring vapor phase and four for measuring particulate phase concentrations of formic acid (HCOOH) and acetic acid (CH_3COOH) were intercompared in central Virginia. HCOOH and CH_3COOH vapors were sampled by condensate, mist, Chromosorb 103 GC resin, NaOH-coated annular denuders, NaOH impregnated quartz filters, K_2CO_3 and Na_2CO_3 impregnated cellulose filters, and Nylasorb membranes. Atmospheric aerosol was collected on Teflon and Nuclepore filters using both hi-vol and lo-vol systems to measure particulate phase concentrations. Samples were collected during 31 discrete day and night intervals of 0.5–2 hour duration over a 4-day period. Performance of the mist chamber and K_2CO_3 impregnated filter techniques were also evaluated using zero air and ambient air spiked with HCOOH_g, CH_3COOH_g, and formaldehyde (CH_2O_g) from permeation sources. Results of this intercomparison show significant systematic and episodic artifacts among many currently deployed measurement systems for HCOOH_g and CH_3COOH_g. The spiking experiments revealed no significant interferences for the mist chamber technique and results generated by the mist chamber and denuder techniques were statistically indistinguishable. The condensate technique showed general agreement with the mist chamber and denuder methods, but episodic bias between these systems was inferred from large and significant differences observed during the first day of sampling. Nylasorb membranes are unacceptable for collecting carboxylic acid vapors as they did not retain HCOOH_g and CH_3COOH_g quantitatively. Strong base impregnated filter and GC resin sampling techniques are prone to large positive interferences apparently resulting, in part, from reactions involving CH_2O_g to generate HCOOH and CH_3COOH subsequent to collection. Significant bias presumably associated with differences in postcollection handling was observed for particulate phase measurements by participating groups. Analytical bias did not contribute significantly to differences in vapor and particulate phase measurements

Future Scenarios of Nitrogen in Europe

The future effects of nitrogen in the environment will depend on the extent of nitrogen use and the practical application techniques of nitrogen in a similar way as in the past. Projections and scenarios are appropriate tools for extrapolating current knowledge into thefuture. However,these tools will not allow future system turnovers to be predicted. Approaches• In principle, scenarios of nitrogen use follow the approaches currently used for air pollution,climate ,or ecosystem projections. Short term projections (to 2030) are developed using a ‘baseline’ path of development,which considers abatement options that are consistent with European policy. For medium-term projections (to 2050) and long-term projections, the European Nitrogen Assessment (ENA) applies a ‘storyline’ approach similar to that used in the IPCC SRES scenarios. Beyond 2050 in particular, such story lines also take into account technological and behavioral shift s.Key findings/state of knowledge• The ENA distinguishes between driver-oriented and effect-oriented factors determining nitrogen use. Parameters that cause changes in nitrogen fixation or application are called drivers. In a driver-based approach, it is assumed that any variation of these parameters will also trigger a change in nitrogen pollution. In an effect-based approach, as the adverse effects of nitrogen become evident inthe environment, introduction of nitrogen abatement legislation requiring the application of more efficient abatement measuresis expected. This approach needs to rely on a target that is likely to be maintained in the future (e.g.human health). Nitrogen abatement legislation basedon such targets will aim to counter any growth in adverse environmental effects that occur as a result of increased nitrogen application.• For combustionand industry, technical fixes forabatement are available. Allscenarios agree in projecting a decrease in NOx emissions.Yet agricultural nitrogen use is expected to remain the leading cause of nitrogen release to the environment, as options to reduce emissions are limited. Thus, major changes will occur only if the extent of agricultural production changes, which may possibly be triggered by decreasing population numbers in Europe.The scenarios presented here project modest changes in NH 3 and N 2 O emissions, or nitrateleaching, but do not agree on the direction of these changes.•Agricultural activity (and thus nitrogen loads to the environment) may decrease strongly if the European population adopts a healthier‘low meat’ diet leading to lower nitrogenlosses related to animal husbandry. Change to a ‘healthy diet’ across the EU, which consists of 63% less meat and eggs, would reduce ammonia emissions from animal production by 48%. However, if an agricultural area previously used for animal feed production is utilized for biofuel crops, additional nitrogen fertilizer maybe required, which will partially offset reductions of nitrogen leakage to the environment. Major uncertainties/challenges• International trade in nitrogen-containing goods (agricultural as well as industrial) represents a key uncertainty and is difficult to project. Estimating the demand for such goods for Europe alone may not at all reflect European production and related environmental effects. The industrial use of nitrogen is alsovery poorly understood, but it is expected to continue to grow considerably. The respective environmental impacts of such products cannot be clearly discerned from statistical information.Recommendations• Scenarios need to be continuously updated in terms of economic, technical, and societal trends to reflect improved understanding of these factors. Using nitrogen budgets as tools could improve the consistency of scenarios.JRC.DDG.H.2-Climate change and air qualit

Urban nitrogen budgets: flows and stock changes of potentially polluting nitrogen compounds in cities and their surroundings–a review

Concepts of material flow and mass consistency of nitrogen compounds have been used to elucidate nitrogen’s fate in an urban environment. While reactive nitrogen commonly is associated to agriculture and hence to large areas, here we have compiled scientific literature on nitrogen budget approaches in cities, following the central role cities have in anthropogenic activities generally. This included studies that specifically dealt with individual sectors as well as budgets covering all inputs and outputs to and from a city across all sectors and media. In the available data set, a clear focus on Asian cities was noted, making full use of limited information and thus enable to quantitatively describe a local pollution situation. Time series comparisons helped to identify trends, but comparison between cities was hampered by a lack of harmonized methodologies. Some standardization, or at least improved reference to relevant standardized data collection along international norms was considered helpful. Analysis of results available pointed to the following aspects that would reveal additional benchmarks for urban nitrogen budgets: analysing the share of nitrogen that is recycled or reused, separating largely independent sets of nitrogen flows specifically between food nitrogen streams and fossil fuel combustion-related flows, and estimating the stock changes for the whole domain or within individual pools

Nitrous oxide scenarios and abatement measures [Chapter 3]

This chapter outlines the scenario framework underpinning the Global Nitrous Oxide Assessment. Scenarios are an opportunity to explore a range of possible futures. Nitrogen is at the heart of many environmental scenarios given its multiple impacts as a pollutant and its key role in food, energy and industrial production

Nitrogen budgets in Europe: a methodology to quantify environmentally relevant flows of reactive nitrogen compounds on a national scale

Reactive nitrogen compounds are responsible for multiple negative impacts while they remain in the environment, changing their state and chemical form. Here we develop a methodology to trace these compounds throughout the environment using a stringent concept to describe their fate consistently and comprehensively. Using an individual country as the system scale, the individual flows of reactive nitrogen are characterized between and within eight pools reflecting human society, economic sectors and environmental spheres, also accounting for transboundary flows, to create a national nitrogen budget. The methodology has been devised for implementation by national agencies in conjunction with greenhouse gas or air pollution emission inventories, hence it links closely with the structures and data derived in these contexts. The guiding methodological principle is the mass conservation of reactive nitrogen, implemented as a material flow analysis that systematically describes all flows and stock changes. Embedding results obtained from five European countries demonstrates the feasibility of the approach. The major environmental pathways of reactive nitrogen compounds can be traced from industrial processes and agricultural production, including the agri-food chain, indicating levers for policy interventions. Spatial and temporal benchmarking of the results demonstrates comparisons between countries or over time. While further results of practical implementation are needed to assess overall robustness, the budget approach allows for multiple opportunities of data checks and verification to visualize the uncertainty associated to many input data, such as lacking information on nitrogen contents and specific flows, or the relevance of so-far unaccounted-for stocks of reactive nitrogen. Useful applications have been identified that link nitrogen budgets to impacts on human health as well as on ecosystems and the climate, indicating that developing and using national nitrogen budgets may shape improved and information-led policies