Emission Factors Values Research Articles

On-board measurement of emissions from freight trucks in urban arterials: Effect of operating conditions, emission standards, and truck size

Diesel trucks contribute significantly to emissions leading to deterioration in urban air quality. Many recent studies have attempted to quantify real-world emissions from trucks in cities. However, studies on real-world emission from trucks in India are scarce. In this study, we measured real-world emissions of gaseous pollutants (CO, HC, and NO) from twenty trucks of different sizes and emission standards. The trucks were classified into three categories (light-duty diesel trucks (LDDTs), medium-duty diesel trucks (MDDTs), and heavy-duty diesel trucks (HDDTs)) based on their gross vehicle weight (GVW). The tested trucks conformed to Bharat Stage (BS) II, BS III, and BS IV emission standards. A vehicle specific power (VSP) based approach was adopted to model the relationship between vehicle activity and emissions. In addition, real-world emission factors of CO, HC, and NO for all the truck types were determined and compared based on their emission standard. Considerable reductions in emission factors were observed from lower to higher emission control standards for all the pollutants. The CO, HC and NO emission factors from the BS II standard LDDTs were 8.05 g/km, 0.86 g/km, and 8.04 g/km, respectively. The CO emission factor decreased by 29% and 65% respectively, for LDDTs and MDDTs with improved emission standards. The HC emissions (g/km) reduction from BS II to BS III for LDDTs and HDDTs were 49% and 8%, respectively. In the case of MDDTs, HC emission factor reduced by 16% from BS II to BS IV. On comparing with ARAI emission standards, we found that the emission factors of the trucks with GVW less than 3500 kg were higher for all the pollutants. In the case of trucks with GVW greater than 3500 kg, the CO emission factor for BS II and BS III complying trucks were higher than standard values while HC emission factors were lower than the standard values. Further, the emission factors of CO and NO from BS IV standard trucks were higher than the standard values. Moreover, emission factor values from our study were higher than that reported in the literature. Although India aims to adopt BS VI emission standards by 2020, phasing out older vehicles will be the key to mitigate emissions from diesel vehicles.

Application of Bayesian statistics to estimate nitrous oxide emission factors of three nitrogen fertilisers on UK grasslands

Trapezoidal integration by linear interpolation of data points is by far the most commonly used method of cumulative flux calculations of nitrous oxide (N2O) in studies that use flux chambers; however, this method is incapable of providing accurate uncertainty estimates. A Bayesian approach was used to calculate N2O emission factors (EFs) and their associated uncertainties from flux chamber measurements made after the application of nitrogen fertilisers, in the form of ammonium nitrate (AN), urea (Ur) and urea treated with Agrotain® urease inhibitor (UI) at four grassland sites in the UK. The comparison between the cumulative fluxes estimated using the Bayesian and linear interpolation methods were broadly similar (R2 = 0.79); however, the Bayesian method was capable of providing realistic uncertainties when a limited number of data points is available. The study reports mean EF values (and 95% confidence intervals) of 0.60 ± 0.63, 0.29 ± 0.22 and 0.26 ± 0.17% of applied N emitted as N2O for the AN, Ur and UI treatments, respectively. There was no significant difference between N2O emissions from the Ur and UI treatments. In the case of the automatic chamber data collected at one site in this study, the data did not fit the log-normal model, implying that more complex models may be needed, particularly for measurement data with high temporal resolution.

Analysis of Greenhouse Gas Emissions in Centralized and Decentralized Water Reclamation with Resource Recovery Strategies in Leh Town, Ladakh, India, and Potential for Their Reduction in Context of the Water–Energy–Food Nexus

With the constant increase of population and urbanization worldwide, stress on water, energy, and food resources is growing. Climate change constitutes a source of vulnerability, raising the importance of implementing actions to mitigate it. Within this, the water and wastewater sector represents an important source of greenhouse gas (GHG) emissions, during both the construction and operation phase. The scope of this study is to analyze the GHG emissions from the current and future water supply scheme, as well as to draw a comparison between possible water reclamation with resource recovery scenarios in the town Leh in India: a centralized scheme, a partly centralized combined with a decentralized scheme, and a household level approach. Precise values of emission factors, based on the IPCC Guidelines for National Greenhouse Gas Inventories, previous studies, and Ecoinvent database, have been adopted to quantify the different emissions. Potential sources of reduction of GHG emissions through sludge and biogas utilization have been identified and quantified to seize their ability to mitigate the carbon footprint of the water and wastewater sector. The results show that the future water supply scheme will lead to a significant increase of the GHG emissions during its operation. Further, it is shown that decentralizing wastewater management in Leh town has the least carbon footprint during both construction and operation phases. These results have implications for cities worldwide.

Nitrous oxide emissions from China's croplands based on regional and crop-specific emission factors deviate from IPCC 2006 estimates

Calculated N2O emission factors (EFs) of applied nitrogen (N) fertilizer are currently based upon a single, universal value advocated by the IPCC (Inter-governmental Panel on Climate Change) even though EFs are thought to vary with climate and soil types. Here, we compiled and analyzed 151 N2O EF values from agricultural fields across China. The EF of synthetic N applied to these croplands was 0.60%, on average, but differed significantly among six climatic zones across the country, with the highest EF found in the north subtropical zone for upland fields (0.93%) and the lowest in the middle subtropical zone for paddy fields (0.20%). Precipitation and soil pH, which showed non-linear relationships with EF, are among the factors governing it, explaining 7.0% and 8.0% of the regional variation in EFs, respectively. Annual precipitation was the key factor regulating N2O emissions from synthetic N fertilizers. Among crop types, legume crops had the highest EFs, which were significantly (P < 0.05) higher than those of cereals. Total soil N2O emissions from fertilized croplands with maize, rice, wheat, and vegetables in China, calculated using the climatic zone (regional) EFs, were estimated to be 239 Gg N yr−1 with an uncertainty of 21%. Importantly, this value was substantially (33%) lower than that (357 Gg N yr−1) derived from the IPCC default EF but close to the 253 Gg N yr−1 estimated using crop-specific EFs. N2O emissions from applied synthetic N fertilizer accounted for 66.5% of the total annual N2O emissions from China's maize, rice, wheat and vegetable fields. Taken together, our study's results strongly suggest that regional EFs should be included for accurate N2O inventories from croplands across China.

Biochar Combined with Vermicompost Increases Crop Production While Reducing Ammonia and Nitrous Oxide Emissions from a Paddy Soil

Organic amendments such as vermicompost and biochar have been reported to enhance soil fertility and crop productivity. However, whether the co-application of both amendments has synergistic effects or whether such benefits are accompanied by the risk of gaseous nitrogen (N) loss in an agroecosystem remains unknown. A soil column experiment with a fully factorial design was conducted using three levels of vermicompost (no dose, low dose (1%, weight:weight), and high dose (3%, weight:weight)) without or with biochar (1%, weight:weight) to investigate their effects on rice growth and gaseous N loss across the crop growing season. Our results demonstrated that synergistic interactions existed between vermicompost and biochar in promoting crop yield. Compared with biochar amendment alone, biochar combined with vermicompost significantly (P < 0.01) increased rice yield by 26.5%–35.3%. However, high dose of vermicompost significantly (P < 0.01) increased the cumulative ammonia (NH3) and nitrous oxide (N2O) emissions. In the presence of vermicompost, the incorporation of biochar amendment significantly (P < 0.01) decreased the cumulative N2O emission by 14.1%–18.6%. The lowest emission factor value of NH3 and N2O was achieved using biochar in combination with low dose of vermicompost. This study revealed that the combination of biochar and moderate dose of vermicompost offers a novel approach to promote crop productivity while reducing the environmental risk.

Pljevlja lignite carbon emission characteristics

The anthropogenic emission of GHG especially CO has to be limited and reduced due to 2 their impact on global warming and climate change. Combustion of fossil fuels in the energy sector has a dominant share in total GHG emissions. In order to reduce GHG emission, European Union established a scheme for GHG allowance trading within the community, and the implementation of the European Union emission trading scheme, which is a key to GHG reduction in a cost-effective way. An important part of emission trading scheme is prescribed methodology for monitoring, reporting, and verification of the emission of GHG including characterization of the local fuels combusted by the energy sector. This paper presents lignite characteristics from open-pit mine Borovica- Pljevlja, which has highest coal production in Montenegro (&gt;1.2 Mt per year), including evaluation of its carbon emission factor based on the laboratory analysis of 72 coal samples. Testing of the samples included proximate and ultimate analysis, as well as, net calorific value determination. In accordance with the obtained results, linear correlations between net calorific value and combustible matter content, carbon content and combustible matter content, hydrogen content and combustible matter content, carbon content and net calorific value, were established. Finally, the non-linear analytical correlation between carbon emission factor and net calorific value for Pljevlja lignite was proposed, as a base for the precise calculation of CO emission evaluation.

Correction of the method of assessing exhaust emission during the flight of the aircraft, including impact of changes in flight altitude on engine performance parameters

Measurements of emission factors of harmful compounds in the exhaust gases of aircraft engines take place during stationary engine tests. Linking the values of emission factors obtained during such tests with the operational parameters of aircraft engines allows to estimate the emission of harmful compounds during the flight of the aircraft. The problem is to determine the impact of changes in flight altitude on the performance of aircraft engines in terms of emission of harmful compounds in the exhaust. Therefore, it is necessary to correct the developed method for determining emissions during the flight of an aircraft. The following article presents the method of estimating the emissions during the flight of the aircraft, taking into account the impact of changes in flight altitude on engine performance parameters, and thus on the emission values of harmful compounds during the flight. In order to carry out the tests, the flight data of the Boeing 787-9 Dreamliner aircraft were used.

Influence of the CO2 emission factor value on the result of the load distribution analysis between the hybrid PV/WT/FC system and the electric power system

This article presents the results of the multicriteria analysis of loads distribution between hybrid power generation system consisting of PV/WT/FC and the electricity system. The simulations were performed for power systems with different structures of the manufacturing sector, and so with different values of the factor of CO2 emission. A decision-making criteria, which were used to compare the relevant scenarios, have been defined.

Trade-off between C and N recycling and N2O emissions of soils with summer cover crops in subtropical agrosystems

The use of summer cover crops (SCCs) as residue inputs in agricultural systems can lead to a potential environmental trade-off between the amount C and N retained and the emission of N as the potent greenhouse gas, nitrous oxide (N2O). Our objectives were to relate N2O fluxes to the quality of SCCs residues and to select SCCs species with high C and N addition and low N2O emissions. We measured SCC biomass production and N2O fluxes after SCCs termination – velvet bean, pearl millet, dwarf pigeonpea, sunn hemp, showy rattlebox and jack bean - under subtropical no-till conditions. The N2O fluxes in the first 30 days after SCCs termination corresponded to 65% of cumulative N2O emissions measured during 165 days in 2010 and 150 days in 2011. The cumulative N2O emissions varied from 0.46 to 1.38 kg N ha-1 and were not proportional to aboveground biomass N addition. Cumulative N2O emissions were positively correlated to water-soluble C and N and the N content of crop residues and negatively correlated to cellulose and hemicellulose content. The N2O emission factor values varied from 0.24 to 0.64% and did not differ among SCCs. Sunn hemp and dwarf pigeonpea are the most suitable species for inclusion in crop systems because they combined high C and N input and low N2O emissions.

Indirect N2O emissions with seasonal variations from an agricultural drainage ditch mainly receiving interflow water

Nitrogen (N)-enriched leaching water may act as a source of indirect N2O emission when it is discharged to agricultural drainage ditches. In this study, indirect N2O emissions from an agricultural drainage ditch mainly receiving interflow water were measured using the static chamber-gas chromatography technique during 2012–2015 in the central Sichuan Basin in southwestern China. We found the drainage ditch was a source of indirect N2O emissions contributing an inter-annual mean flux of 6.56 ± 1.12 μg N m−2 h−1 and a mean indirect N2O emission factor (EF5g) value of 0.03 ± 0.003%. The mean EF5g value from literature review was 0.51%, which was higher than the default EF5g value (0.25%) proposed by the Intergovernmental Panel on Climate Change (IPCC) in 2006. Our study demonstrated that, more in situ observations of N2O emissions as regards N leaching are required, to account for the large variation in EF5g values and to improve the accuracy and confidence of the default EF5g value. Indirect N2O emissions varied with season, higher emissions occurred in summer and autumn. These seasonal variations were related to drainage water NO3−-N concentration, temperature, and precipitation. Our results showed that intensive precipitation increased NO3−-N concentrations and N2O emissions, and when combined with warmer water temperatures, these may have increased the denitrification rate that led to the higher summer and autumn N2O emissions in the studied agricultural drainage ditch.

WASTEWATER SPECIFIC EMISSION FACTOR FROM COMMUNAL WASTEWATER TREATMENT PLANT (WWTP)

Greenhouse gasses (GHG) that produced by anaerobic digestion of wastewater consists of CH 4 gas and NO 2 gas. Beside the data of specific activity, the specific emission factor also plays important part to determinate GHG emission. The aim of this paper is to know specific emission factor value from communal wastewater treatment plant (WWTP), as an input to determinate GHG emission for determination of GHG emission reduction rate. The data was collected by taking sample of BOD, CH 4 gas, and CO 2 gas from communal WWTPs. Sampling location were communal WWTPs in Jakarta City, Bandung City, and Yogyakarta City. Those WWTPs using anaerobic baffle reactor as their treatment system with capacity varied between 40-200 EP. The parameters were BOD and CH 4 that measured using grab sampling in the morning and evening. Data analyzed by quantitative methods. The specific emission factor value was determined from CH 4 gas measurement which affected by wastewater treatment unit dimension, gas catcher chamber, and air suction pump capacity. The analysis results showed specific emission factor for communal WWTPs from the three cities is 0.00171 kg CH 4 /kg BOD. The value has bid difference when compared to IPCC’s default that is 0.48 kg CH 4 /kg BOD. This is due to the formation of CH4 gas and CO2 gas was strongly influenced by environmental condition in real time condition. This factor is not taken into consideration in IPCC’s default.

Emission factors of atmospheric and climatic pollutants from crop residues burning

ABSTRACTBiomass burning is a common agricultural practice, because it allows elimination of postharvesting residues; nevertheless, it involves an inefficient combustion process that generates atmospheric pollutants emission, which has implications on health and climate change. This work focuses on the estimation of emission factors (EFs) of PM2.5, PM10, organic carbon (OC), elemental carbon (EC), carbon monoxide (CO), carbon dioxide (CO2), and methane (CH4) of residues from burning alfalfa, barley, beans, cotton, maize, rice, sorghum, and wheat in Mexico. Chemical characteristics of the residues were determined to establish their relationship with EFs, as well as with the modified combustion efficiency (MCE). Essays were carried out in an open combustion chamber with isokinetic sampling, following modified EPA 201-A method. EFs did not present statistical differences among different varieties of the same crop, but were statistically different among different crops, showing that generic values of EFs for all the agricultural residues can introduce significant uncertainties when used for climatic and atmospheric pollutant inventories. EFs of PM2.5 ranged from 1.19 to 11.30 g kg−1, and of PM10 from 1.77 to 21.56 g kg−1. EFs of EC correlated with lignin content, whereas EFs of OC correlated inversely with carbon content. EFs of EC and OC in PM2.5 ranged from 0.15 to 0.41 g kg−1 and from 0.33 to 5.29 g kg−1, respectively, and in PM10, from 0.17 to 0.43 g kg−1 and from 0.54 to 11.06 g kg−1. CO2 represented the largest gaseous emissions volume with 1053.35–1850.82 g kg−1, whereas the lowest was CH4 with 1.61–5.59 g kg−1. CO ranged from 28.85 to 155.71 g kg−1, correlating inversely with carbon content and MCE. EFs were used to calculate emissions from eight agricultural residues burning in the country during 2016, to know the potential mitigation of climatic and atmospheric pollutants, provided this practice was banned.Implications: The emission factors of particles, short-lived climatic pollutants, and atmospheric pollutants from the crop residues burning of eight agricultural wastes crops, determined in this study using a standardized method, provides better knowledge of the emissions of those species in Latin America and other developing countries, and can be used as inputs in air quality models and climatic studies. The EFs will allow the development of more accurate inventories of aerosols and gaseous pollutants, which will lead to the design of effective mitigation strategies and planning processes for sustainable agriculture.

The injector location impact on the fuel combustion process in a direct gasoline injection system

The article contains an analysis of the fuel dose combustion phenomena and exhaust emissions in a direct injection system of an SI engine for variable injector location in the combustion chamber. The research performed is a continuation of the research presented in the article CE-2018-104. The tests were performed using the AVL Fire 2017 simulation environment. 27 injector placement combinations in three planes were analyzed: axial distance from the cylinder axis, injector depth relative to the head and angular position relative to the cylinder axis. An optimal solution was chosen, taking into account the significance of individual indicators. It was shown that the greatest impact in terms of the most advantageous combustion process indicators is the injector setting depth in the combustion chamber cavity, while the distance from the cylinder axis is of secondary importance. The smallest changes in the combustion and emission factors values are seen with the change of the injector placement angle (in the value range used in this study).

Chemical characterization of fine particulate matter emitted by peat fires in Central Kalimantan, Indonesia, during the 2015 El Niño

Abstract. Fine particulate matter (PM2.5) was collected in situ from peat smoke during the 2015 El Niño peat fire episode in Central Kalimantan, Indonesia. Twenty-one PM samples were collected from 18 peat fire plumes that were primarily smoldering with modified combustion efficiency (MCE) values of 0.725–0.833. PM emissions were determined and chemically characterized for elemental carbon (EC), organic carbon (OC), water-soluble OC, water-soluble ions, metals, and organic species. Fuel-based PM2.5 mass emission factors (EFs) ranged from 6.0 to 29.6 g kg−1 with an average of 17.3 ± 6.0 g kg−1. EC was detected only in 15 plumes and comprised ∼ 1 % of PM mass. Together, OC (72 %), EC (1 %), water-soluble ions (1 %), and metal oxides (0.1 %) comprised 74 ± 11 % of gravimetrically measured PM mass. Assuming that the remaining mass is due to elements that form organic matter (OM; i.e., elements O, H, N) an OM-to-OC conversion factor of 1.26 was estimated by linear regression. Overall, chemical speciation revealed the following characteristics of peat-burning emissions: high OC mass fractions (72 %), primarily water-insoluble OC (84 ± 11 %C), low EC mass fractions (1 %), vanillic to syringic acid ratios of 1.9, and relatively high n-alkane contributions to OC (6.2 %C) with a carbon preference index of 1.2–1.6. Comparison to laboratory studies of peat combustion revealed similarities in the relative composition of PM but greater differences in the absolute EF values. The EFs developed herein, combined with estimates of the mass of peat burned, are used to estimate that 3.2–11 Tg of PM2.5 was emitted to atmosphere during the 2015 El Niño peatland fire event in Indonesia. Combined with gas-phase measurements of CO2, CO, CH4, and volatile organic carbon from Stockwell et al. (2016), it is determined that OC and EC accounted for 2.1 and 0.04 % of total carbon emissions, respectively. These in situ EFs can be used to improve the accuracy of the representation of Indonesian peat burning in emission inventories and receptor-based models.

PBDE emission from E-wastes during the pyrolytic process: Emission factor, compositional profile, size distribution, and gas-particle partitioning.

Polybrominated diphenyl ether (PBDE) pollution in E-waste recycling areas has garnered great concern by scientists, the government and the public. In the current study, two typical kinds of E-wastes (printed wiring boards and plastic casings of household or office appliances) were selected to investigate the emission behaviors of individual PBDEs during the pyrolysis process. Emission factors (EFs), compositional profile, particle size distribution and gas-particle partitioning of PBDEs were explored. The mean EF values of the total PBDEs were determined at 8.1 ± 4.6 μg/g and 10.4 ± 11.3 μg/g for printed wiring boards and plastic casings, respectively. Significantly positive correlations were observed between EFs and original addition contents of PBDEs. BDE209 was the most abundant in the E-waste materials, while lowly brominated and highly brominated components (excluding BDE209) were predominant in the exhaust fumes. The distribution of total PBDEs on different particle sizes was characterized by a concentration of finer particles with an aerodynamic diameter between 0.4 μm and 2.1 μm and followed by less than 0.4 μm. Similarly, the distribution of individual species was dominated by finer particles. Most of the freshly emitted PBDEs (via pyrolysis) were liable to exist in the particulate phase with respect to the gaseous phase, particularly for finer particles. In addition, a linear relationship between the partitioning coefficient (KP) and the subcooled liquid vapor pressure (PL0) of the different components indicated non-equilibrium gas-particle partitioning during the pyrolysis process and suggested that absorption by particulate organic carbon, rather than surface adsorption, governed gas-particle partitioning.

Soil pH as the chief modifier for regional nitrous oxide emissions: New evidence and implications for global estimates and mitigation.

Nitrous oxide (N2 O) is a greenhouse gas that also plays the primary role in stratospheric ozone depletion. The use of nitrogen fertilizers is known as the major reason for atmospheric N2 O increase. Empirical bottom-up models therefore estimate agricultural N2 O inventories using N loading as the sole predictor, disregarding the regional heterogeneities in soil inherent response to external N loading. Several environmental factors have been found to influence the response in soil N2 O emission to N fertilization, but their interdependence and relative importance have not been addressed properly. Here, we show that soil pH is the chief factor explaining regional disparities in N2 O emission, using a global meta-analysis of 1,104 field measurements. The emission factor (EF) of N2 O increases significantly (p<.001) with soil pH decrease. The default EF value of 1.0%, according to IPCC (Intergovernmental Panelon Climate Change) for agricultural soils, occurs at soil pH 6.76. Moreover, changes in EF with N fertilization (i.e. ΔEF) is also negatively correlated (p<.001) with soil pH. This indicates that N2 O emission in acidic soils is more sensitive to changing N fertilization than that in alkaline soils. Incorporating our findings into bottom-up models has significant consequences for regional and global N2 O emission inventories and reconciling them with those from top-down models. Moreover, our results allow region-specific development of tailor-made N2 O mitigation measures in agriculture.

First approach to exhaust emissions characterization of light vehicles in Montevideo, Uruguay

According to Act No. 17283 of November 28th, 2000, air quality protection is a general concern in Uruguay. Road transport is the main emitter of nitrogen oxides (NOx), as the National Inventory of Air Emissions 2006 stated. Actually, it is responsible for the emissions of 59.8% of NOx and 28% of carbon monoxide (CO). The number of households owning a car in Uruguay increased from 29% in 2005 to 39% in 2013, enhancing the importance of characterizing the vehicular emissions of the national fleet. In this paper, a first approach for this characterization is presented. It was carried out on a sample of 11 light vehicles currently in use in Montevideo city, Uruguay. On-road emissions measurements of nitrogen monoxide (NO), carbon monoxide (CO) and carbon dioxide (CO2) were carried out for calculating the emission factors. The fitness of the set of calculated emission factors values to different probability distributions was tested. When possible, the 95% confidence intervals were obtained for the mean emission factors (CO: 2.0g/km±0.3g/km; NO: 0.05g/km±0.01g/km). This procedure was useful to obtaining accurate confidence intervals from a relatively small sample size. Finally, the link between atmospheric emissions and some other parameters of the tested vehicles was studied using a multivariate statistical tool, highlighting the strong increase in carbon monoxide emissions observed for low vehicles speeds and fuel efficiencies.

Open burning as a source of dioxins

ABSTRACTThis review critically collates data on the emissions of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and dioxin-like biphenyls (dl-PCBs), or in brief dioxins from a wide range of open burning sources. Open burning started raising attention in the nineties and has then been identified as one of the major global sources of dioxins, especially since evident guided emissions—principally from waste incineration and metallurgy—have been drastically curtailed. During combustion, dioxin emissions appear related to the proximate and ultimate analysis of the materials burning, to different combustion parameters (temperature, turbulence oxygen, etc.), to the successive phases in the development of a fire (flaming vs. smoldering), and to other factors influencing upon dioxins formation, such as heating, halogens, soot, ash, and catalytic transition metals. Although the roles of these factors are analyzed and discussed, they still remain difficult to evaluate and quantify, resulting in emission factor values ranging over several orders of magnitude, even after carefully controlled, repetitive experiments. Comprehensive comparisons of dioxins emission data are presented for both biogenic and anthropogenic sources, as well as some possible countermeasures toward reduction of dioxins from open burning.

Ammonia and greenhouse gas emissions from a subtropical wheat field under different nitrogen fertilization strategies

Minimizing soil ammonia (NH3) and nitrous oxide (N2O) emission factors (EFs) has significant implications in regional air quality and greenhouse gas (GHG) emissions besides nitrogen (N) nutrient loss. The aim of this study was to investigate the impacts of different N fertilizer treatments of conventional urea, polymer-coated urea, ammonia sulfate, urease inhibitor (NBPT, N-(n-butyl) thiophosphoric triamide)-treated urea, and nitrification inhibitor (DCD, dicyandiamide)-treated urea on emissions of NH3 and GHGs from subtropical wheat cultivation. A field study was established in a Cancienne silt loam soil. During growth season, NH3 emission following N fertilization was characterized using active chamber method whereas GHG emissions of N2O, carbon dioxide (CO2), and methane (CH4) were by passive chamber method. The results showed that coated urea exhibited the largest reduction (49%) in the EF of NH3-N followed by NBPT-treated urea (39%) and DCD-treated urea (24%) over conventional urea, whereas DCD-treated urea had the greatest suppression on N2O-N (87%) followed by coated urea (76%) and NBPT-treated urea (69%). Split fertilization of ammonium sulfate-urea significantly lowered both NH3-N and N2O-N EF values but split urea treatment had no impact over one-time application of urea. Both NBPT and DCD-treated urea treatments lowered CO2-C flux but had no effect on CH4-C flux. Overall, application of coated urea or urea with NPBT or DCD could be used as a mitigation strategy for reducing NH3 and N2O emissions in subtropical wheat production in Southern USA.

Country-specific emission and oxidation factors for determination of CO2 emissions from combustion of coal and lignite in the Czech Republic

ABSTRACTCombustion of lignite and coal comprises the most important part of CO2 emissions in the Czech Republic (CR). The IPCC methodology on national greenhouse gas inventories provides default values of emission factors for the basic tier (the simplest level of methodological approach), including those for lignite and coal, which do not represent the specific national conditions. Therefore, this methodology indicates that more accurate country-specific emission factors based on national data should be used for the significant categories of sources, called key categories. This paper presents the results of recent research that was concerned with updating country-specific emission factors, which would be able to accurately describe CO2 emissions from combustion of coal and lignite in the Czech Republic for the whole time period from 1990 to the present year (2016). Development of these factors was based on the evaluation of relevant correlation dependence of emission factor on net calorific value. In addition, the research was supplemented by assessment of relevant country-specific oxidation factors for lignite and coal.