In this study, uncertainties related to NH₃ concentration, emission factor, and emission factor estimation in the exhaust gas of the steel sintering furnace using COG (coke oven gas) among the by-product gas generated in steel production was estimated to identify the missing source. By measuring the NH₃ concentration in the exhaust gas of steel sintering furnace using COG, a concentration between 0.02 and 0.12 ppm was found, with an average concentration of 0.06 ppm, confirming the emissions of NH₃. Using this measurement of the NH₃ concentration, an NH₃ emission factor of 0.0061 kg NH₃/ton was derived. The uncertainty of the developed NH₃ emission factor of the sintering furnace using COG was analyzed using a Monte Carlo simulation. Consequently, the uncertainty range of NH₃ emission factor of the sintering furnace using COG was derived to be −11.4% to +12.89% at the 95% confidence level. According to the results of this study, NH₃ emissions occur from the use of COG, yielding values higher than the NH₃ emission factor resulting from the use of LNG(liquefied natural gas) in combustion facilities. It should be recognized that it is a missing emission source and the corresponding emission should be calculated.

The greenhouse gas emissions of the waste incineration sector account for approximately 43% of the total GHG emissions and represent the majority of the CO₂ emissions from waste in Korea. Improving the reliability of the GHG inventory of the waste incineration sector is an important aspect for the examination of global GHG emission management according to the Paris Agreement. In this study, we introduced a statistical approach to analyze seasonal changes through analysis of waste composition and CO₂ concentration in Municipal Solid Waste incinerators and applied the methodology to one case study facility. The analysis results in the case study showed that there was no seasonal variation in waste composition and CO₂ concentrations, except for wood. Wood is classified as biomass, and the GHG emissions caused by biomass incineration are reported separately, indicating that the effect of an MSW incinerator on GHG emissions is not significant. Therefore, the seasonal effect of CO₂ concentration or waste composition may not be an impact when calculating GHG emissions from case study facilities’ MSW incinerators. This study proposed an approach for analyzing factors that affect the GHG inventory reliability by analyzing seasonal characteristics and variation through the statistical analysis, which are used for the calculation of the GHG emissions of an MSW incinerator.

NH₃ is one of the major substances contributing to the secondary generation of PM2.5; therefore, management is required. In Korea, the management of NH₃ is insufficient, and the emission factor used by EPA is the same as the one used when calculating emissions. In particular, waste incineration facilities do not currently calculate NH₃ emissions. In the case of combustion facilities, the main ammonia emission source is the De-NOx facility, and, in the case of a power plant with a De-NOx facility, NH₃ emission is calculated. Therefore, in the case of a Municipal Solid Waste (MSW) incinerator with the same facility installed, it is necessary to calculate NH₃ emissions. In this study, the necessity of developing NH₃ emission factors for an MSW incinerator and calculating emission was analyzed. In addition, elements to be considered when developing emission factors were analyzed. The study found that the NH₃ emission factors for each MSW incinerator technology were calculated as Stoker 0.010 NH₃ kg/ton and Fluidized Beds 0.004 NH₃ kg/ton, which was greater than the NH₃ emission factor 0.003 NH₃ kg/ton for the MSW incinerator presented in EMEP/EEA (2016). As a result, it was able to identify the need for the development of NH₃ emission factors in MSW incinerators in Korea. In addition, the statistical analysis of the difference between the incineration technology of MSW and the NH₃ emission factor by the De-NOx facility showed a difference in terms of both incineration technology and De-NOx facilities, indicating that they should be considered together when developing the emission factor. In addition to MSW, it is believed that it will be necessary to review the development of emission factors for waste at workplaces and incineration facilities of sewage sludge.

In the case of sewage sludge, as direct landfilling was recently prohibited, it is treated through incineration. Among the air pollutants discharged through the incineration of sewage sludge, NOx and SOx are considered secondary substances of PM2.5 and are being managed accordingly. However, NH₃, another of the secondary substances of PM2.5, is not well managed, and the amount of NH₃ discharged from sewage sludge incineration facilities has not been calculated. Therefore, in this study, we sought to determine whether NH₃ is discharged in the exhaust gas of a sewage sludge incineration facility, and, when discharged, the NH₃ emission factor was calculated, and the necessity of the development of the emission factor was reviewed. As a result of the study, it was confirmed that the amount of NH₃ discharged from the sewage sludge incineration facility was 0.04 to 4.47 ppm, and the emission factor was calculated as 0.002 kg NH₃/ton. The NH₃ emission factor was compared with the NH₃ emission factor of municipal solid waste proposed by EMEP/EEA (European Monitoring and Evaluation Programme/European Environment Agency) because the NH₃ emission factor of the sewage sludge incineration facility had not been previously determined. As a result of the comparison, the NH₃ emission factor of EMEP/EEA was similar to that of municipal solid waste, confirming the necessity of developing the NH₃ emission factor of the sewage sludge incineration facility. In addition, the evaluation of the uncertainty of the additionally calculated NH₃ emission factor was conducted quantitatively and the uncertainty range was presented for reference. In the future, it is necessary to improve the reliability of the NH₃ emission factor of sewage sludge incineration facilities by performing additional analysis with statistical representation. In addition, the development of NH₃ emission factors for industrial waste incineration facilities should be undertaken.

In this study, the emission factor and concentration of ammonia from industrial waste incineration facilities were analyzed through actual measurements. The ammonia emission factor was calculated and the difference in ammonia emission factor for each type of incineration was confirmed through the Mann–Whitney U test. As a result of analyzing 279 samples, the NH₃ emission factor of the SNCR facility of stoker types was 0.012 kgNH₃/ton, and the NH₃ emission factor of the SNCR facility of the rotary kiln methods was 0.014 kgNH₃/ton. Additionally, the NH₃ emission factor of this study was higher than the NH₃ emission factor (0.003 kgNH₃/ton) suggested by Kang’s study (0.009 kgNH₃/ton) and EMEP/EEA (2006). There is a need to develop an NH₃ emission factor that takes into account the characteristics of Korea, since it is largely different from the NH₃ emission factor of EMEP/EEA. As a result of statistical analysis of the stoker type and the rotary kiln method, the null hypothesis that there is no difference between each type was adopted (p-value > 0.05), indicating that there was no statistical difference in the ammonia emission factors of the stoker type and the rotary kiln type.

This study has statistically analyzed the effect of boiler type and model year on CH₄ emission factors, focusing on liquefied natural gas (LNG)—the most commonly used fuel in South Korean manufacturing combustion facilities. Samples were collected from the boilers of 39 manufacturing combustion facilities that use LNG fuel. The CH₄ emission factors were developed based on 4 overhead fire-tube boilers, 14 once-through boilers, 14 vertical boilers with vertical water tubes, and 7 other boilers. This resulted in an average value of 0.11 CH₄ kg/TJ, which is considerably lower than the Intergovernmental Panel on Climate Change (IPCC) 1996 guidelines(G/L) emission factor of 5 CH₄ kg/TJ currently used in South Korea. In the Kruskal–Wallis test results, the significance probability was greater than 0.05 for the boiler types and ages, and there was no major difference in the average distributions, according to the boiler type or age. Therefore, according to the results of this study, the differences in the CH₄ emission factors according to the boiler types and ages are not statistically large, and it was determined that there is no major difference even when the emission factors are applied to different fuel types. However, there was a major difference when the developed factors were compared to the CH₄ emission factor proposed by the IPCC. Thus, there is a need to develop manufacturing combustion CH₄ emission factors that reflect national characteristics.