The estimation of N2O emissions from municipal solid waste incineration facilities: The Korea case

The greenhouse gases (GHGs) generated in municipal solid waste (MSW) incineration are carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O). In South Korea case, the total of GHGs from the waste incineration facilities has been increasing at an annual rate 10%. In these view, waste incineration facilities should consider to reduce GHG emissions.This study is designed to estimate the N₂O emission factors from MSW incineration plants, and calculate the N₂O emissions based on these factors. The three MSW incinerators examined in this study were either stoker or both stoker and rotary kiln facilities. The N₂O concentrations from the MSW incinerators were measured using gas chromatography-electron capture detection (GC-ECD) equipment.The average of the N₂O emission factors for the M01 plant, M02 plant, and M03 plant are 71, 75, and 153 g-N₂O/ton-waste, respectively. These results showed a significant difference from the default values of the intergovernmental panel on climate change (IPCC), while approaching those values derived in Japan and Germany. Furthermore, comparing the results of this study to the Korea Energy Economics Institute (KEEI) (2007) data on waste incineration, N₂O emissions from MSW incineration comprised 19% of the total N₂O emissions.     

Influence of aeration on CH4, N2O and NH3 emissions during aerobic composting of a chicken manure and high C/N waste mixture

Co-composting of chicken manure, straw and dry grasses was investigated in a forced aeration system to estimate the effect of aeration rates on NH₃, CH₄ and N₂O emissions and compost quality. Continuous measurements of gas emissions were carried out and detailed gas emission patterns were obtained using an intermittent-aeration of 30 min on/30 min off at rates of 0.01 (A1), 0.1 (A2) and 0.2 (A3) m³ min⁻¹ m⁻³. Concentrations of CH₄ and N₂O at the low aeration rate (A1) were significantly greater than those at the other two rates, but there was no significant difference between the A2 and A3 treatments. CH₄ and N₂O emissions for this mixture could be controlled when the composting process was aerobic and ammonia emissions were reduced at a lower aeration rate. Comparison of CH₄, N₂O, NH₃ emissions and compost quality showed that the aeration rate of the A2 treatment was superior to the other two aeration rates.     

Reducing the environmental impact of methane emissions from dairy farms by anaerobic digestion of cattle waste

Four dairy cattle farms considered representative of Northern Spain milk production were studied. Cattle waste was characterised and energy consumption in the farms was inventoried. Methane emissions due to slurry/manure management and fuel consumption on the farms were calculated. The possibility of applying anaerobic digestion to the slurry to minimise emissions and of using the biogas produced to replace fossil fuels on the farm was considered. Methane emissions due to slurry management (storage and use as fertiliser) ranged from 34 to 66 kg CH₄ cow⁻¹ year⁻¹ for dairy cows and from 13 to 25 kg CH₄ cow⁻¹ year⁻¹ for suckler calves. Cattle on these farms are housed for most of the year, and the contribution from emissions from manure dropped in pastures is insignificant due to the very low methane conversion factors. If anaerobic digestion were implemented on the farms, the potential GHG emissions savings per livestock unit would range from 978 to 1776 kg CO₂ eq year⁻¹, with the main savings due to avoided methane emissions during slurry management. The methane produced would be sufficient to supply digester heating needs (35-55% of the total methane produced) and on-farm fuel energy requirements.     

Nitrous Oxide Emissions from Two Riparian Ecosystems: Key Controlling Variables

Nitrous oxide (N₂O) emissions were measured weekly to fortnightly between April 2001 and March 2002 from two riparian ecosystems drainingdifferent agricultural fields. The fields differed in the nature of the crop grown and the amount of fertiliser applied. Soil water content and soil temperature were very important controls of N₂O emission rates, with a ‘threshold’ response at 24% moisture content (by volume) and 8 °C, below which N₂O emission was very low.N₂O fluxes were higher at the site that had receivedthe most fertiliser N, but NO₃ ^- was not a limiting factor at either site. There was also a ‘threshold’ effect of rainfall, in which major rainfall events (≥10 mm) triggered a pulse of high N₂O emission if none of the other environmental factors were limiting. These results suggest the existence of multiple controls on N₂O emissions operating at a range of spatial and temporal scales and that non-linear relationships, perhaps with a hierarchical structure, are needed to model these emissions from riparian ecosystems.     

The Influence of Atmospheric N Deposition on Nitrous Oxide and Nitric Oxide Fluxes and Soil Ammonium and Nitrate Concentrations

The deposition of atmospheric N to soils provides sources of available N to the nitrifying and denitrifying microbial community and subsequently influences the rate of NO and N₂O emissions from soil. We have investigated the influence of three different sources of enhanced N deposition on NO and N₂O emissions 1) elevated NH₃ deposition to woodlands downwind of poultry and pig farms, 2) increased wet cloud and occult N deposition to upland forest and moorland and 3) enhanced N deposition to trees as NO ₃ ^– and NH ₄ ⁺ aerosol. Flux measurements of NO and N₂O were made using static chambers in the field or intact and repacked soil cores in the laboratory and determination of N₂O by gas chromatography and of NO by chemiluminescence analysis. Rates of N deposition to our study sites were derived from modelled estimates of N deposition, NH₃ concentrations measured by passive diffusion and inference from measurements of the ²¹⁰Pb inventory of soils under tree canopies compared with open grassland. NO and N₂O emissions and KCl-extractable soil NH ₄ ⁺ and NO ₃ ^– concentrations all increased with increasing N deposition rate. The extent of increase did not appear to be influenced by the chemical form of the N deposited. Systems dominated by dry-deposited NH₃ downwind of intensive livestock farms or wet-deposited NH ₄ ⁺ and NO ₃ ^– in the upland regions of Britain resulted in approximately the same linear response. Emissions of NO and N₂O from these soils increased with both N deposition and KCl extractable NH ₄ ⁺ , but the relationship between NH ₄ ⁺ and N deposition (ln NH ₄ ⁺ = 0.62 ln N_deposition + 0.21, r ² = 0.33, n = 43) was more robust than the relationship between N deposition and soil NO and N₂O fluxes.     

Composting of waste algae: A review

Although composting has been successfully used at pilot scale to manage waste algae removed from eutrophied water environments and the compost product applied as a fertiliser, clear guidelines are not available for full scale algae composting. The review reports on the application of composting to stabilize waste algae, which to date has mainly been macro-algae, and identifies the peculiarities of algae as a composting feedstock, these being: relatively low carbon to nitrogen (C/N) ratio, which can result in nitrogen loss as NH₃ and even N₂O; high moisture content and low porosity, which together make aeration challenging; potentially high salinity, which can have adverse consequence for composting; and potentially have high metals and toxin content, which can affect application of the product as a fertiliser. To overcome the challenges that these peculiarities impose co-compost materials can be employed.     

Sulphur mineralization kinetics of cattle manure and green waste compost in soils.

Sulphur mineralization of cattle manure (CM) and green waste compost (GWC) added to six agricultural soils with different chemical properties was monitored over 10 weeks in a laboratory incubation experiment. Although the amount of sulphur was higher in CM than in GWC, the cumulative SO4(2-)-S values in GWC-treated soils were higher than in soil amended with CM. The percentages of mineralized S were always higher in GWC-treated soil (in the range 1.3-8.5%) than in CM-treated soil (in the range 0.9-3.8%). In three of the six soils, particularly for CM, an immobilization of sulphur was observed. Three kinetic models were evaluated for their suitability to describe the mineralization process. The first-order model best described S mineralization for both amended and control soils. The GWC substantially increased the amount of potentially mineralizable S (S0) relative to the controls. In GWC-treated soils, the rates of S mineralization (k) were higher than rates in the controls. The k of CM-amended soils was often lower than the k of control soils. Parameters derived from the model were tested as indices for assessing the relationships between S mineralization and soil characteristics. The S0 was positively correlated to the amount of cumulative SO4(2-)-S and also to the content of organic C, N and S in soil.     

The influence of atmospheric n deposition on nitrous oxide and nitric oxide fluxes and soil ammonium and nitrate concentrations

The deposition of atmospheric N to soils provides sources of available N to the nitrifying and denitrifying microbial community and subsequently influences the rate of NO and N₂O emissions from soil. We have investigated the influence of three different sources of enhanced N deposition on NO and N₂O emissions 1) elevated NH₃ deposition to woodlands downwind of poultry and pig farms, 2) increased wet cloud and occult N deposition to upland forest and moorland and 3) enhanced N deposition to trees as NO^? ₃ and NH⁺ ₄ aerosol. Flux measurements of NO and N₂O were made using static chambers in the field or intact and repacked soil cores in the laboratory and determination of N₂O by gas chromatography and of NO by chemiluminescence analysis. Rates of N deposition to our study sites were derived from modelled estimates of N deposition, NH₃ concentrations measured by passive diffusion and inference from measurements of the ²¹⁰Pb inventory of soils under tree canopies compared with open grassland. NO and N₂O emissions and KCl-extractable soil NH⁺ ₄ and NO^? ₃ concentrations all increased with increasing N deposition rate. The extent of increase did not appear to be influenced by the chemical form of the N deposited. Systems dominated by dry-deposited NH₃ downwind of intensive livestock farms or wet-deposited NH⁺ ₄and NO^? ₃ in the upland regions of Britain resulted in approximately the same linear response. Emissions of NO and N₂O from these soils increased with both N deposition and KCl extractable NH⁺ ₄, but the relationship between NH⁺ ₄ and N deposition (ln NH⁺ ₄ = 0.62 ln N_deposition+0.21, r ² = 0.33, n = 43) was more robust than the relationship between N deposition and soil NO and N₂O fluxes.     

Gas production, composition and emission at a modern disposal site receiving waste with a low-organic content

AV Miljø is a modern waste disposal site receiving non-combustible waste with a low-organic content. The objective of the current project was to determine the gas generation, composition, emission, and oxidation in top covers on selected waste cells as well as the total methane (CH₄) emission from the disposal site. The investigations focused particularly on three waste disposal cells containing shredder waste (cell 1.5.1), mixed industrial waste (cell 2.2.2), and mixed combustible waste (cell 1.3). Laboratory waste incubation experiments as well as gas modeling showed that significant gas generation was occurring in all three cells. Field analysis showed that the gas generated in the cell with mixed combustible waste consisted of mainly CH₄ (70%) and carbon dioxide (CO₂) (29%) whereas the gas generated within the shredder waste, primarily consisted of CH₄ (27%) and nitrogen (N₂) (71%), containing no CO₂. The results indicated that the gas composition in the shredder waste was governed by chemical reactions as well as microbial reactions. CH₄ mass balances from three individual waste cells showed that a significant part (between 15% and 67%) of the CH₄ generated in cell 1.3 and 2.2.2 was emitted through leachate collection wells, as a result of the relatively impermeable covers in place at these two cells preventing vertical migration of the gas. At cell 1.5.1, which is un-covered, the CH₄ emission through the leachate system was low due to the high gas permeability of the shredder waste. Instead the gas was emitted through the waste resulting in some hotspot observations on the shredder surface with higher emission rates. The remaining gas that was not emitted through surfaces or the leachate collection system could potentially be oxidized as the measured oxidation capacity exceeded the potential emission rate. The whole CH₄ emission from the disposal site was found to be 820 ± 202 kg CH₄ d⁻¹. The total emission rate through the leachate collection system at AV Miljø was found to be 211 kg CH₄ d⁻¹. This showed that approximately ¼ of the emitted gas was emitted through the leachate collections system making the leachate collection system an important source controlling the overall gas migration from the site. The emission pathway for the remaining part of the gas was more uncertain, but emission from open cells where waste is being disposed of or being excavated for incineration, or from horizontal leachate drainage pipes placed in permeable gravel layers in the bottom of empty cells was likely.     

Home composting as an alternative treatment option for organic household waste in Denmark: An environmental assessment using life cycle assessment-modelling

An environmental assessment of the management of organic household waste (OHW) was performed from a life cycle perspective by means of the waste-life cycle assessment (LCA) model EASEWASTE. The focus was on home composting of OHW in Denmark and six different home composting units (with different input and different mixing frequencies) were modelled. In addition, incineration and landfilling was modelled as alternatives to home composting. The most important processes contributing to the environmental impact of home composting were identified as greenhouse gas (GHG) emissions (load) and the avoided emissions in relation to the substitution of fertiliser and peat when compost was used in hobby gardening (saving). The replacement of fertiliser and peat was also identified as one of the most sensible parameters, which could potentially have a significant environmental benefit. Many of the impact categories (especially human toxicity via water (HTw) and soil (HTs)) were affected by the heavy metal contents of the incoming OHW. The concentrations of heavy metals in the compost were below the threshold values for compost used on land and were thus not considered to constitute a problem. The GHG emissions were, on the other hand, dependent on the management of the composting units. The frequently mixed composting units had the highest GHG emissions. The environmental profiles of the home composting scenarios were in the order of −2 to 16 milli person equivalents (mPE) Mg⁻¹ wet waste (ww) for the non-toxic categories and −0.9 to 28 mPE Mg⁻¹ ww for the toxic categories. Home composting performed better than or as good as incineration and landfilling in several of the potential impact categories. One exception was the global warming (GW) category, in which incineration performed better due to the substitution of heat and electricity based on fossil fuels.     

Winter and Spring Thaw Measurements of N2O,NO and NOx Fluxes using a Micrometeorological Method

The impact of nitrogen fertilizers on gaseous emissions duringwinter and spring-thaw is not well understood and was the objective of this research. Using a micrometeorological method,N₂O, NO and NO_x fluxes from ryegrass were measured from November 1997 to March 1998. Three different mineralfertilizers were applied in November: urea (U), slow-release urea(SRU) and ammonium nitrate (AN). N₂O emissions during the winter were small, increasing significantly in March. Total losses of N₂O-N were significantly higher from SRU and U plots, with winter N₂O emissions accounting for 50% of annual losses. Nitric oxide fluxes from all plots weresmall during the measurement period (<0.9 ng N m^-2 s^-1). The NO fluxes from U and AN fertilized plots were significantly higher than from SRU and control plots. NO₂ fluxes were always negative (–6 ng N m^-2 s^-1)indicating deposition, but decreased to –2 ng N m^-2s^-1 when snow was present on the soil surface. Our resultsindicate that the form of inorganic N applied has an effect on NO+ N₂O emissions but not on NO₂ fluxes.Sponsored by CAPES – Brasília, Brazil     

Spatially Disaggregated Inventories of Soil NO and N2O Emissions for Great Britain

Estimates of soil N₂O and NOemissions at regional and country scales arehighly uncertain, because the most widely usedmethodologies are based on few data, they do notinclude all sources and do not account forspatial and seasonal variability. To improveunderstanding of the spatial distribution of soilNO and N₂O emissions we have developedsimple multi-linear regression models based onpublished field studies from temperate climates.The models were applied to create spatialinventories at the 5 km² scale of soil NOand N₂O emissions for Great Britain. The N₂O regression model described soilN₂O emissions as a function of soil N input,soil water content, soil temperature and land useand provided an annual N₂O emission of 128 kt N₂O-N yr^-1. Emission rates largerthan 12 kg N₂O-N ha^-1 yr^-1 werecalculated for the high rainfall grassland areasin the west of Great Britain.Soil NO emissions were calculated using tworegression models, which described NO emissionsas a function of soil N input with and without afunction for the water filled pore space. Thetotal annual emissions from both methods, 66 and7 kt NO-N yr^-1, respectively, span the rangeof previous estimates for Great Britain.     

Quantification of multiple methane emission sources at landfills using a double tracer technique

A double tracer technique was used successfully to quantify whole-site methane (CH₄) emissions from Fakse Landfill. Emissions from different sections of the landfill were quantified by using two different tracers. A scaled-down version of the tracer technique measuring close-by to localized sources having limited areal extent was also used to quantify emissions from on-site sources at the landfill facility, including a composting area and a sewage sludge storage pit. Three field campaigns were performed. At all three field campaigns an overall leak search showed that the CH₄ emissions from the old landfill section were localized to the leachate collection wells and slope areas. The average CH₄ emissions from the old landfill section were quantified to be 32.6 ± 7.4 kg CH₄ h⁻¹, whereas the source at the new section was quantified to be 10.3 ± 5.3 kg CH₄ h⁻¹. The CH₄ emission from the compost area was 0.5 ± 0.25 kg CH₄ h⁻¹, whereas the carbon dioxide (CO₂) and nitrous oxide (N₂O) flux was quantified to be in the order of 332 ± 166 kg CO₂ h⁻¹ and 0.06 ± 0.03 kg N₂O h⁻¹, respectively. The sludge pit located west of the compost material was quantified to have an emission of 2.4 ± 0.63 kg h⁻¹ CH₄, and 0.03 ± 0.01 kg h⁻¹ N₂O.     

Determination of nitrous oxide, methane, and ammonia emissions from a swine waste composting process

The amounts of harmful gas emissions from the process of composting swine waste were determined using an experimental composting apparatus. Forced aeration (19.2–96.1 l/m³/min) was carried out continuously, and exhaust gases were collected and analyzed periodically. With weekly turning and the addition of a bulking agent in order to decrease the moisture content and increase air permeability, the temperature of most of the contents rose to 70°C and composting was complete within 3–5 weeks. NH₃, CH₄, and N₂O emissions were high in the early stage of composting. About 10%–25% of the nitrogen in the raw material was lost as NH₃ gas during composting. The emission rate of NH₃ mainly depended on the aeration rate, so that as the aeration rate rose, the level of NH₃ emissions increased. The CH₄ and N₂O emissions could be kept lower with adequate treatment at more than 40 l/m³/min aeration. N₂O may be mainly the result of the denitrification of NO _x -N in the additional matured compost used as a composting accelerator. Received: September 11, 1998 / Accepted: November 8, 1999     

Emissions of ammonia and greenhouse gases during combined pre-composting and vermicomposting of duck manure

Combined pre-composting and vermicomposting has shown potential for reclamation of solid wastes, which is a significant source of ammonia (NH₃), and greenhouse gases (GHG), including nitrous oxide (N₂O), methane (CH₄), and carbon dioxide (CO₂). Earthworms and amendments may both affect physico-chemical characteristics that control gas-producing processes, and thus affect NH₃ and GHG emissions. Here, we used two-way ANOVA to test the effects of addition of reed straw and combined addition of reed straw and zeolite on NH₃ and GHG emissions during pre-composting of duck manure, either with or without a follow-up phase of vermicomposting. Results showed that cumulative N₂O, CH₄, and CO₂ emissions during pre-composting and vermicomposting ranged from 92.8, 5.8, and 260.6 mg kg^?1 DM to 274.2, 30.4, and 314.0 mg kg^?1 DM, respectively. Earthworms and amendments significantly decreased N₂O and CH₄ emissions. Emission of CO₂ was not affected by earthworms, but increased in responses to addition of reed straw. Cumulative NH₃ emission ranged from 3.0 to 8.1 g kg^?1 DM, and was significantly decreased by reed straw and zeolite addition. In conclusion, combined pre-composting and vermicomposting with reed straw and zeolite addition would be strongly recommended in mitigating emissions of N₂O, CH₄, and NH₃ from duck manure. Moreover, this method also provides nutrient-rich products that can be used as a fertilizer.     

Greenhouse gas emissions from home composting of organic household waste

The emission of greenhouse gases (GHGs) is a potential environmental disadvantage of home composting. Because of a lack of reliable GHG emission data, a comprehensive experimental home composting system was set up. The system consisted of six composting units, and a static flux chamber method was used to measure and quantify the GHG emissions for one year composting of organic household waste (OHW). The average OHW input in the six composting units was 2.6–3.5 kg week^?1 and the temperature inside the composting units was in all cases only a few degrees (2–10 °C) higher than the ambient temperature. The emissions of methane (CH₄) and nitrous oxide (N₂O) were quantified as 0.4–4.2 kg CH₄ Mg^?1 input wet waste (ww) and 0.30–0.55 kg N₂O Mg^?1 ww, depending on the mixing frequency. This corresponds to emission factors (EFs) (including only CH₄ and N₂O emissions) of 100–239 kg CO₂-eq. Mg^?1 ww. Composting units exposed to weekly mixing had the highest EFs, whereas the units with no mixing during the entire year had the lowest emissions. In addition to the higher emission from the frequently mixed units, there was also an instant release of CH₄ during mixing which was estimated to 8–12% of the total CH₄ emissions. Experiments with higher loads of OHW (up to 20 kg every fortnight) entailed a higher emission and significantly increased overall EFs (in kg substance per Mg^?1 ww). However, the temperature development did not change significantly. The GHG emissions (in kg CO₂-eq. Mg^?1 ww) from home composting of OHW were found to be in the same order of magnitude as for centralised composting plants.     

Field scale N2O flux measurements from grassland using eddy covariance

In order to assess nitrous oxide (N₂O) emissions from typical intensively managed grassland in northern Britain fluxes were measured by eddy covariance using tuneable diode laser absorption spectroscopy from June 2002 to June 2003 for a total period of 4000 h. With micrometeorological techniques it is possible to obtain a very detailed picture of the fluxes of N₂O at field scale (10³–10⁴ m²), which are valuable for extrapolation to regional scales. In this paper three of the four fertilizer applications were investigated in detail. N₂O emissions did not always show a clear response. Hourly fluxes were very large immediately after the June 2002 nitrogen fertilizer application, peaking at 2.5 mg N₂O–N m^–2 s^–1. Daily fluxes were averaging about 300 ng N₂O m^–2 s^–1 over the 4 days following fertilizer application. The response of N₂O emissions was less evident after the August fertilization, although 2 days after fertilizer application an hourly maximum flux of 554 ng N₂O–N m^–2 s^–1 was registered. For the rest of August the flux was undetectable. The differences between fertilization events can be explained by different environmental conditions, such as soil temperature and rainfall. A fertiliser-induced N₂O emission was not observed after fertilizer application in March 2003, due to lack of rainfall. The total N₂O flux from June 2002 to June 2003 was 5.5 kg N₂O–N ha^–1y^–1, which is 2.8% of the total annual N fertilizer input.     

Chemical,physical and microbial properties and microbial diversity in manufactured soils produced from co-composting green waste and biosolids

The effects of adding biosolids to a green waste feedstock (100% green waste, 25% v/v biosolids or 50% biosolids) on the properties of composted products were investigated. Following initial composting, 20% soil or 20% fly ash/river sand mix was added to the composts as would be carried out commercially to produce manufactured soil. Temperatures during composting reached 50 °C, or above, for 23 days when biosolids were included as a composting feedstock but temperatures barely reached 40 °C when green waste alone was composted. Addition of biosolids to the feedstock increased total N, EC, extractable NH₄, NO₃ and P but lowered pH, macroporosity, water holding capacity, microbial biomass C and basal respiration in composts. Additions of soil or ash/sand to the composts greatly increased the available water holding capacity of the materials. Principal component analysis (PCA) of PCR-DGGE 16S rDNA amplicons separated bacterial communities according to addition of soil to the compost. For fungal ITS-RNA amplicons, PCA separated communities based on the addition of biosolids. Bacterial species richness and Shannon’s diversity index were greatest for composts where soil had been added but for fungal communities these parameters were greatest in the treatments where 50% biosolids had been included. These results were interpreted in relation to soil having an inoculation effect and biosolids having an acidifying effect thereby favouring a fungal community.     

Spatial variability of nitrous oxide and methane emissions from an MBT landfill in operation: Strong N2O hotspots at the working face

Mechanical biological treatment (MBT) is an effective technique, which removes organic carbon from municipal solid waste (MSW) prior to deposition. Thereby, methane (CH₄) production in the landfill is strongly mitigated. However, direct measurements of greenhouse gas emissions from full-scale MBT landfills have not been conducted so far. Thus, CH₄ and nitrous oxide (N₂O) emissions from a German MBT landfill in operation as well as their concentrations in the landfill gas (LFG) were measured. High N₂O emissions of 20–200 g CO₂ eq. m^?2 h^?1 magnitude (up to 428 mg N m^?2 h^?1) were observed within 20 m of the working face. CH₄ emissions were highest at the landfill zone located at a distance of 30–40 m from the working face, where they reached about 10 g CO₂ eq. m^?2 h^?1. The MBT material in this area has been deposited several weeks earlier. Maximum LFG concentration for N₂O was 24.000 ppmv in material below the emission hotspot. At a depth of 50 cm from the landfill surface a strong negative correlation between N₂O and CH₄ concentrations was observed. From this and from the distribution pattern of extractable ammonium, nitrite, and nitrate it has been concluded that strong N₂O production is associated with nitrification activity and the occurrence of nitrite and nitrate, which is initiated by oxygen input during waste deposition. Therefore, CH₄ mitigation measures, which often employ aeration, could result in a net increase of GHG emissions due to increased N₂O emissions, especially at MBT landfills.     

Variability of nitrous oxide and carbon dioxide emissions continuously measured in solid waste incinerators

Nitrous oxide and carbon dioxide were continuously measured and variability of emission factors (EFs) was evaluated in five municipal waste incinerators (MWIs) and four industrial waste incinerators (IWIs) from 24 to 86 days between 2008 and 2011. N₂O EFs were calculated by Monte Carlo simulation and mean N₂O EFs were 7.1, 107, 127, 219 g N₂O/ton waste combusted in MWIs with selective catalytic reduction (SCR) for NOx control, MWIs with selective non-catalytic reduction (SNCR), IWIs with SNCR, and a MWI using fluidized bed with SNCR, respectively. Climate-relevant CO₂ EFs ranged from 0.45 to 0.72 ton CO₂/ton waste combusted in MWIs. Maximum values of upper limit for 95% confidence intervals (CIs) of N₂O EFs estimated in each MWIs with SCR, MWIs with SNCR, IWIs with SNCR were 185, 94, 101% of mean N₂O EFs, respectively. Meanwhile, maximum values of upper limit for 95% CIs of CO₂ EFs were much lower as between 18 and 36% in those facilities. 84% CIs of mean N₂O EFs in MWIs with SNCR and IWIs with SNCR were overlapped indicating those values are not significantly different.