Odor emissions from sewer systems are a persistent environmental concern in urban areas, particularly in combined sewer systems where septic tanks are widely used. However, the contribution of septic tanks as sources of sewer odor has not been sufficiently quantified. This study investigated the characteristics of hydrogen sulfide (H2S) generation in septic tanks and evaluated its potential influence on sewer odor, as well as the effectiveness of odor mitigation technologies. Field investigations were conducted in combined sewer areas to measure aqueous H2S concentrations in septic tanks. The results showed that H2S concentrations in septic tanks were not significantly affected by septic tank capacity (ANOVA, p > 0.05), suggesting that tank size or user population is not a primary determinant of sulfide generation. In contrast, aqueous H2S exhibited a positive correlation with chemical oxygen demand (COD), indicating that organic matter availability plays an important role in sulfide production through microbial sulfate reduction processes. A significant relationship was observed between aqueous H2S in septic tanks and gaseous H2S measured at catch basins, demonstrating that sulfide derived from septic tanks can transfer to the sewer atmosphere and potentially impact human odor exposure in urban environments. In addition, the performance of odor control technologies applied to septic tanks was evaluated with aeration-based technologies found to significantly reduce H2S concentrations. These findings suggest that septic tanks can serve as important sources of sewer odor highlighting the need for effective management and proper operation of septic tank odor control systems in combined sewer areas.

Odorous emissions from large industrial complexes exhibit significant spatial and temporal variability, which complicates quantitative evaluation and source identification. Odor perception may occur even at low concentrations, and emission characteristics are strongly influenced by industrial processes, meteorological conditions, and local topography. Therefore, odor management strategies based solely on compliance with emission standards have inherent limitations. The Yeosu National Industrial Complex was designated as an odor management area in 2019, and annual surveys of complex odor dilution ratios and specified odor substances have been conducted since then. Despite the accumulation of monitoring data, odor complaints from nearby residential areas have continued. In this study, multi-year (2020-2024) odor monitoring data were integrated with complaint records, and GIS-based mapping and visualization were applied to examine the spatial distribution characteristics of measured odor levels and complaint locations. Map-based visualization facilitated visual comparison of complaint locations and monitoring sites and enabled a comparative assessment between monitoring sites and complaint locations. The results revealed clear spatial heterogeneity among monitoring sites. In particular, the A3 monitoring site recorded the highest annual average dilution ratio, indicating persistent structural characteristics of odor emissions in that area. Although measured odor intensity was relatively higher in summer, complaint frequency peaked in spring and autumn, suggesting that meteorological conditions and human exposure patterns significantly influence perceived odor nuisance. These findings demonstrate that measured odor intensity alone does not fully explain complaint occurrence and highlight the necessity of integrated odor management approaches that incorporate spatial dispersion characteristics, seasonal variability, and community exposure factors. The results can serve as a foundational basis for improving monitoring site placement and establishing spatially differentiated odor management policies.

Odorous compounds from the operation of wastewater treatment plants (WWTPs) have increasingly become public health concerns and civil complaints. This study identifies priority management stages in WWTPs by quantitatively analyzing the distribution of complex odor and designated odor substances across key processes using a dimensionless tool (the Odor Activity Value, OAV), while providing a statistical basis and operational strategies for efficient odor mitigation in public facilities. Although there was a very poor correlation between designated odorous concentrations and complex odor level (dilution ratio), the application of the OAV yielded much more accurate results with a strong correlation (R2 = 0.7) specifically at high-temperature condition. Odor potential in the wastewater treatment processes fluctuates substantially depending on the specific unit. Statistical analysis using Kruskal–Wallis tests demonstrated that influent and sludge treatment process (return flow and centrate) produce much higher odor intensities compared to the biological reactor and secondary clarifier. Based on PERMANOVA analysis, differences in the profiles of complex odor and the OAVs of designated odorants across 6 treatment stages explained 64.1% of the total variance. Principal Coordinates Analysis (PCoA) showed that sludge treatment processes form a distinct, unique cluster, whereas sewage treatment streams present a more gradual transition of odor profiles. Statistical assessment using the Mann-Whitney U test demonstrated that mean odorants levels did not have considerable shift under high-temperature and low-temperature conditions. However, the sensory perception in higher temperatures enhanced relative to the OAVs. In conclusion, the OAV is an effective dimensionless tool, as it establishes priorities in odor management and control, offering a practical supplementary indicator for addressing civil complaints. These findings provide a robust foundation for optimizing deodorization systems designs and operational efficiency of odor mitigation systems within WWTPs.

Odor complaint data collected in Seoul between 2014 and 2021 exhibited significant departures from normality. To address this, a Box-Cox transformation (l = 0.1149) was applied to stabilize variance and improve distributional normality. The transformed data were then evaluated for normality using the Shapiro-Wilk, Kolmogorov- Smirnov, and Anderson-Darling tests, all of which failed to reject the null hypothesis of normality (p > 0.05). However, the corresponding test statistics (0.989, 0.039, and 5.757, respectively) were close to their respective critical thresholds, indicating a substantial improvement in distributional normality. Based on the Box-Cox transformed dataset (l = 0.1149), the inlier range was defined as 4~190 cases/day, while observations of ≤3 cases/day and ≥191 cases/day were classified as low and high outliers, respectively. Within the inlier range, the meteorological variables exerting the strongest influence on IOCE (cases/day) were air (49.5), dew point (48.2), and surface temperature (48.1), whereas precipitation showed the weakest influence (39.7). The highest SROCE interval within the inlier range was associated with mean meteorological conditions of air (27.7±1.0oC), dew point (15.2±1.2oC) and surface temperature (30.4±1.1oC), and precipitation (0.6±1.8 mm). By contrast, the corresponding conditions in the high-outlier range were 19.6±1.2oC, 14.7±1.7oC, 23.1±1.4oC, and 0.3±0.7 mm, respectively. Across both the inlier and high-outlier ranges, the mean variation rate (VMF, %) of meteorological observations within the highest SROCE interval across the 13 meteorological factors was approximately ±11%. However, in the high-outlier range, mean meteorological conditions within complaint-concentrated intervals exhibited noticeable divergence from those observed in the inlier range. This study elucidated the meteorological drivers of IOCE and peak SROCE conditions across both inlier and high-outlier ranges. In addition to facilitating odor occurrence forecasting based on meteorological predictions, these findings provide a scientific basis for managing odor emission sources from specific facilities and regulated areas, extending beyond community level odors in residential areas.

This study examines odor survey results from 2020 and 2024 in the D-City Dyeing Industrial Complex to identify the structural limitations of Korea’s odor control system under the Odor Prevention Act and to assess their administrative implications. Despite significant improvements in both complex and designated odor substances within legal standards, residents’ complaints persisted. This discrepancy suggests that the concentration-based regulatory framework fails to reflect the sensory perception of intermittent odors shaped by meteorological, topographical, and receptor factors. Moreover, the reporting system for odor-emitting facilities is not a legally binding administrative act, limiting local governments’ ability to impose optional measures such as complete process enclosure. These institutional and spatial constraints are transferred to front-line administration, where overburdened officials exhibit street-level bureaucratic behaviors (such as simplified compliance and reactive complaint handling) as adaptive strategies. Drawing on Lipsky’s (1980) theory of street-level bureaucracy, this study interprets such practices as rational responses to structural constraints and proposes policy reforms emphasizing financial support, the adoption of odor-frequency indicators, and the reinforcement of administrative capacity. The findings indicate that effective odor management requires an integrated approach combining institutional reform with strengthened capacity for local implementation.

국내 양돈 산업의 대형화와 산업화에 따라 축산 악취에 대한 민원 발생이 지속적으로 증가하고 있다. 돼지 분뇨 에서 주로 발생하는 악취는 후각적 불쾌감을 유발할 뿐 아니라, 돼지의 폐사율 증가, 생산성 저하, 농장 근로자의 작업 환경 악화 등 다양한 부정적 영향을 미친다. 따라서 전국적인 양돈장 환경 개선과 효과적인 악취 저감 대책의 마련이 필요하다. 본 연구에서는 천연 추출물 복합체인 바 이오매직®의 양돈장 악취 저감 효과와 그에 따른 부수적 인 생리학적 개선 효과를 평가하였다. 본 실험에 사용된 바이오매직®은 오렌지, 파파야, 라임을 발효하여 제조한 것으로, 우선 돼지 농장에서 분리된 메티실린 내성 황색 포도상구균(MRSA)을 대상으로 항균 활성을 평가하였다. CLSI 기준에 따른 최소억제농도(MIC) 및 최소살균농도 (MBC) 시험 결과, 바이오매직®은 15개 MRSA 균주에 대 해 낮은 MIC와 MBC 값을 나타내어 우수한 항균 활성을 보였다. 양돈장 내 주요 악취 유발 물질인 암모니아(NH3), 황화수소(H2S), 이산화탄소(CO2)에 대한 저감 효과를 조사 한 결과, 바이오매직®을 살포한 후 NH3와 C O2 농도가 유 의적으로 감소하였으나(P<0.05), H2S는 연구 전기간에 걸 쳐 측정되지 않았다. 또한, 돼지의 스트레스 수준은 혈중 코르티솔 농도를 효소면역측정법(ELISA)으로 측정하여 평 가하였다. 그 결과, 실험군의 코르티솔 농도 감소율이 대조 군에 비해 유의적으로 높게 나타났다(P<0.05). 스트레스 감 소에 따른 면역력 향상 여부를 평가하기 위해 유세포 분석 (flow cytometry)을 실시한 결과, 항원제시세포의 비율이 다 소 증가하였고, CD4-T cell 비율이 유의적으로 증가하였다 (P<0.05). 이상의 결과를 종합하면, 본 실험에서 사용한 바 이오매직®은 양돈장에서 악취 저감뿐만 아니라 돼지의 스 트레스 완화 및 면역 기능 향상에도 긍정적인 효과를 나타 내었다. 이러한 개선 효과는 폐사율 감소 및 생산성 향상, 나아가 동물 복지 증진에 기여할 수 있을 것으로 판단된다.

In response to the rapid increase in odor-related complaints during the 1970s, the Japanese Ministry of the Environment developed a method for measuring lowconcentration, multi-component odorants. This method was conceptually similar to the ASTM syringe method. To overcome the limitations of small volume dilutions, odor-free 3 L polyethylene terephthalate (PET) bags were introduced. Using the triangle odor bag method, panelists were asked to identify one odorous bag among three choices, and odor concentration was determined based on each panelist’s individual threshold. Japan has also introduced an odor index, which integrates odor concentration and intensity, allowing intuitive assessment of human perception. Compared with Korea, differences exist in panelist selection, reference odor intensity levels, the number of panelists required, and threshold calculations, leading to variations in measured odor concentrations. Since the early 2000s, comparative studies have demonstrated that the Japanese method is comparable to European olfactory measurement practices. The triangle odor bag method has been recently become widely adopted across Asia, while dynamic olfactometry has been standardized under ISO standards, facilitating international harmonization of odor measurement and regulatory frameworks. This study provides an overview of the Japanese olfactory measurement method and the procedure for calculating the odor index.

This study investigated odor generation and external leakage characteristics in a combined sewer system through field monitoring of manholes, catch basins, and box culverts. Odor samples were analyzed for malodor intensity in terms of the dilutionto- threshold (D/T) ratio using the air dilution sensory (ADS) test. In addition to the ADS tests, 22 offensive odorants as defined in the Korean Malodor Prevention Act were quantified. Among the odorants monitored, hydrogen sulfide showed not only the highest concentrations but was also the most frequently detected, indicating representative odor compounds. The mean hydrogen sulfide concentration reached 1,132 ppbv, with a maximum of 13,709 ppbv, corresponding to complex odor concentrations of up to 1,442 dilution-to-threshold units. On average, approximately 13% of the internal sewer odors escaped through manhole openings, which could easily cause odor nuisance exceeding the legal threshold at boundary lines. A comparison with national odor management standards indicated that the current regulations, based solely on in-pipe hydrogen sulfide concentration, do not adequately represent human sensory perception. The findings highlight the need to establish practical odor-control criteria that consider external leakage and perceptual intensity for effective sewer odor management in urban environments.

This study established a method for the simultaneous quantitative analysis of 84 odorous compounds by determining proton transfer reaction rate constants, fragmented ion patterns, and product ion yield ratios through experiments on 33 target compounds and by incorporating previously reported data. In this research, a protontransfer- reaction time-of-flight mass spectrometer (PTR-ToF-MS), a real-time analytical instrument, was employed to quantitatively analyze odorants in process streams and final outlet gases from two wastewater consignment treatment facilities (Facility A and Facility B). The expected odor intensity (EOI) estimation method was further applied to identify the primary odor contributors. Among the final outlet gases, the top five odorcausing substances in Facility A were n-pentanal, acetaldehyde, methylmercaptan, n-hexanol, and n-butanal, while the top five odor-causing substances in Facility B were n-decanal, n-nonanal, acetaldehyde, n-butanal, and n-propanol. The cumulative odor contribution rates of these top five odorants were 94.7% and 91.9% for Facilities A and B, respectively. Although PTR-ToF-MS has inherent limitations in distinguishing isomers and isobars, their individual quantification was achieved through complementary identification and separation by TD-GC-MS. This study provides a basis for simplifying quality control in odor analysis compared with conventional trace-level odor testing methods and proposes a more scientific and effective approach for addressing odor problems.

This study was conducted to analyze odor regulation policies of major countries and explore development directions for Korea’s odor management system through international comparison. Korea has achieved significant progress in odor management over the past 20 years since the enactment of the Odor Prevention Act in 2004, including the establishment of real-time monitoring systems, integrated complaint management systems, and scientific management infrastructure in major odor management areas such as Sihwa-Banwol Industrial Complex and metropolitan landfills in Incheon and Daejeon. To identify potential development directions, a literature review and comparative analysis were conducted on four regions: the United States, the European Union, Japan, and Singapore. The analysis revealed that each region has developed unique approaches: Japan’s Odor Judge system (involving 3,352 active professionals) for measurement standardization; the United States’s citizen science-based monitoring systems, such as the Odor Explore project that utilizes community participation; the EU’s preventive management policies through the application of Best Available Techniques (BAT) and land use planning integration; and Singapore’s systematic management approach through its myENV app and urban planning integration. Based on Korea’s existing achievements and international experiences, this study identified eight development areas, including measurement system standardization, management scope expansion, integrated management system enhancement, real-time monitoring implementation, technology development investment, complaint resolution mechanism improvement, preventive management system enhancement, and information transparency enhancement. This study proposes development directions that build upon Korea’s current infrastructure and policy achievements, considering the country’s unique socio-economic conditions and environmental characteristics. These directions are expected to contribute to the continuous advancement of Korea’s odor management system while leveraging existing strengths and addressing future challenges.

The textile tentering process generates exhaust gases characterized by elevated temperature and humidity, accompanied by complex odors, fine particulate matter, and visible white smoke, all of which frequently contribute to public grievances and environmental concerns. This study evaluated a field-installed, multi-stage emissioncontrol system consisting of a scrubber, a wet electrostatic precipitator (WEFC), and a heat exchanger, with emphasis on the effect of routine plate cleaning over a ht ree-month operation. Real-time monitoring at 5-minute intervals measured temperature, humidity, total volatile organic compounds (TVOCs), particulate matter (PM2.5, PM10, TSP), and odor intensity. Odor activity values (OAVs) and odor contributions (OC) were determined from samples collected according to the Korean Odor Measurement Standard. The emission-control system reduced exhaust temperature from 150oC to below 50oC while maintaining stack outlet temperature differences within 5oC, thereby suppressing visible white smoke. The multistage system achieved mean removal efficiencies of 88.6±5.0% for TVOCs and 96.2±6.5% for PM10, with a gravimetric PM10 removal of 99.4%. Weekly cleaning of the electrostatic plates constrained day-to-day variability in odor and PM levels within ±10%, significantly lowering the frequency of white-smoke episodes. Isovaleraldehyde and acetaldehyde accounted for >90% of total OAVs, indicating the need for supplementary treatment targeting aldehydes. These results provide quantitative evidence to guide maintenance scheduling and emission-control policy for the textile processing industry.

This study analyzed the odor contribution rate using AERMOD at odor emission facilities in an urban industrial area (North-Daejeon, Korea) where residential facilities, industrial complexes, and public environmental facilities are mixed. When comparing the average odor emission concentration by prevention facility, the multistage treatment method including oxidation and combustion was about three times more effective in reducing the concentration than the commonly used biofilter and scrubber. These results suggest the importance of management aspects of prevention facilities such as biofilters and cleaning towers to improve treatment efficiency. Currently, management of odor emission facilities is being conducted in terms of instantaneous odor concentration management. Due to the limitations of this management method, research results show that some workplaces ranked 7th in terms of momentary odor concentration level, but in terms of emissions, they soared to 2nd place, indicating that management from the perspective of emissions as well as concentration is necessary for odor management. The odor impact in the study area varies by season, but public environmental facilities have an impact of 62~76% in spring, summer, and winter, and odor emission facilities in industrial complexes have an impact of 66% in autumn. It can be inferred from these results that the odor impact of public environmental facilities would be low because they are located away from residential areas, but the results confirmed through this study showed that the concentration and emission levels of prevention facilities operated in public environmental facilities were relatively higher than those of odor-emitting facilities in industrial complexes.

In this study, we investigated the characteristics of meteorological factors influencing odor emissions based on odor complaint records and meteorological observation data collected from 2014 to 2021 in Seoul, a megacity with a high population density and no regulated facilities or management zones apart from public environmental infrastructure and neighborhood living facilities. A total of 134,976 odor complaints were recorded over eight years (2,922 days), with a daily peak of 946 cases. From 2018 onward, daily complaints consistently exceeded 200 cases, reaching their highest level in 2019. Complaints were regularly and intensively concentrated during specific periods of the year. Among meteorological factors, dry tide time and dominant wind direction exhibited bimodal distributions within the observation range, while the other 11 meteorological factors were concentrated at a single value. The average meteorological conditions during the period with the highest number of odor complaints and observation days were: temperature 24.2oC, surface temperature 26.7oC, local pressure 1,000.4 hPa, sea-level pressure 1,010.8 hPa, vapor pressure 4.3 hPa, solar irradiance 10.5 MJ/m2, precipitation 0.6 mm, relative humidity 61.5%, wind speed 2.2 m/ s, and dominant wind direction 57.9o. These factors corresponded with the periods of highest odor complaints and observation days; however, dew point temperatures (15.3oC and 19.1oC), dry tide times (14.7 hours and 9.7 hours), and sunshine times (15.1 hours and 9.0 hours) did not coincide with those periods. The meteorological factors with the highest odor complaint emission rates (SROCE, cases/day) across 13 sections, ranked in descending order, were: dry tide time (73.5), surface temperature (67.7), solar irradiance (65.1), sea-level pressure (64.3), temperature (62.7), local pressure (62.7), dew point temperature (60.3), vapor pressure (58.7), sunshine times (54.1), relative humidity (53.1), wind speed (51.2), dominant wind direction (48.7), and precipitation (46.3). The intensity of odor complaint emission (IOCE, cases/day), calculated across the entire meteorological observation range, was highest in the following order: solar irradiance (63.8), dry tide time (60.5), sunshine times (60.3), local pressure (57.2), surface temperature (57.1), sea-level pressure (57.0), temperature (56.4), vapor pressure (55.8), dew point temperature (55.7), relative humidity (49.4), dominant wind direction (49.2), wind speed (49.0), and precipitation (46.5). The IOCE for solar irradiance was 37.2% higher than that for precipitation, which had the lowest IOCE. Additionally, the average IOCE of sunlightrelated meteorological factors such as dry tide time, sunshine times, and solar irradiance was 61.5 cases/day, which is 29.5% higher than that of moisture-related factors, including precipitation and relative humidity (47.5 cases/day). These results suggest that sunlight-related factors significantly contribute to odor complaints. This study evaluated the characteristics of odor emissions associated with complaints within the meteorological observation range, identified meteorological factors corresponding to the highest observed odor emissions, and assessed the contribution of these factors to odor emissions based on the IOCE metric. Based on these results, we anticipate being able to predict odor emission levels using weather forecast data.

This paper focuses on methods for quantifying landfill gas emissions, including odor, odor generation mechanisms, odor emission characteristics according to the time of waste deposition, and odor measurement data from landfills. This study analyzed the concentration ranges and median values of 22 odor compounds measured at landfill gas collection wells and various landfill surface locations across both domestic and international landfill sites. These locations included active operational areas, final cover surfaces, and leachate treatment zones. The odor with the highest measured concentration at the landfill gas collection well was H2S (with a median value of 818,616 mg m–3). During landfill operations and on the surface of uncovered landfill layers, the concentrations of NH3 (with a median value of 1,613 mg m–3) and H2S (with a median value of 279.5 mg m–3) were found to be high . Concentrations of toluene, xylene, ketones, and sulfide odors were also high at covered landfill surfaces. Additionally, NH3, styrene, and H2S had high concentrations in the leachate treatment area. The odor intensity, measured on the surface of covered sanitary landfills for domestic waste, ranged from 6 to 2,080 mg m–3 (dilution to threshold). The concentrations of NH3 and H2S were relatively high in domestic sanitary landfills. The odorous compounds that contributed the most to odor intensity were nitrogen-containing odors, sulfur-containing odors, and aldehydes. In order to effectively manage landfill odors in the future, research should be continuously conducted to accurately measure and predict odor emission fluxes from landfills. In addition, it will be necessary to develop emission reduction technologies that take into account landfill odor emission characteristics.

This study evaluated the field applicability of a real-time odor monitoring system combined with ozone water spraying technology to effectively control odors generated in livestock manure recycling facilities. Research was conducted at a Natural Circulation Agriculture Center located in N City, where concentrations of ammonia (NH3), hydrogen sulfide (H2S), and volatile organic compounds (VOCs) were measured in real time. Based on real-time data, ozone water was sprayed to assess the odor reduction rate, and the impact on surrounding areas was predicted through odor dispersion modeling. The results showed that the ammonia concentration measured at the upper section of the liquid aeration tank before ozone water spraying was 8.02 ppm, exceeding the emission limit of 1 ppm. VOCs were also found to have significantly contributed to odor generation. However, after spraying ozone water at a rate of 7 L/min and maintaining a concentration of 2.5 mg/L, ammonia was reduced by approximately 50%, and VOCs were reduced by about 98%, demonstrating a strong odor-reducing effect. Odor dispersion modeling using the CALPUFF modeling system simulated the range of odor dispersion before and after ozone water spraying. The results indicated that after ozone water spraying, the ammonia concentration at the facility boundary met the emission limit, effectively suppressing odor dispersion. In particular, the ozone water spraying system linked with the real-time sensor enabled automated odor control based on real-time data, demonstrating its potential for resolving odor complaints and ensuring compliance with environmental regulations.

This study measured and analyzed the discharge concentration and characteristics of odor substances emitted from the discharge outlets of asphalt manufacturing facilities in South Korea. Measured factors included flow rate, composite odors, and 22 designated odor substances. After applying the dilution factor of composite odors emitted from 33 asphalt manufacturing facilities located in various regions to the composite odor emission standard of 500 times, it was found that more than half of these facilities exceeded the emission standard. The contribution rate of the designated odor substances from the discharge outlets was the highest for acetaldehyde at over 50%, followed by hydrogen sulfide and methyl mercaptan. The correlation between composite odors and the concentration of major designated odor substances was analyzed, and it was found that methyl mercaptan and acetaldehyde showed some correlation with the composite odor dilution factor. The methyl mercaptan odor intensity corresponding to the odor intensity of 4.5 to 5 ppb, which is the allowable odor dilution multiple emission standard of the odor emission source outlet, was estimated to be approximately 1.6 to 2.2 ppb, and the corresponding methyl mercaptan emission concentration range was estimated to be 0.98 to 2.02 ppb. The composite odor emission coefficient of asphalt concrete manufacturing facilities was estimated to be higher for general asphalt concrete than for asphalt concrete recycling facilities, and the composite odor emission coefficient of newly produced general asphalt concrete was estimated to be greater than that of recycled asphalt concrete. In terms of fuel usage, the composite odor emission coefficient of facilities that used Bunker C fuel oil was estimated to be higher than that of facilities powered by LPG and LNG fuel. It was deemed necessary to select 2 to 3 major designated odor substances that are correlated with the composite odor dilution factor for each major odor emission source, set the designated odor substance concentration corresponding to the composite odor dilution factor emission allowance standard, and review a plan to monitor the designated odor substances at the emission point.

This study investigated the correlation between compound malodor and total hydrocarbons (THC) to evaluate the potential use of THC as a predictor of compound malodor. A total of 87 samples were analyzed from five target facilities: two petrochemical manufacturing facilities (A, B), a wastewater treatment facility (C), a recycled plastic injection molding facility (D), and a surfactant manufacturing facility (E). The correlation coefficients of compound malodor and THC for each facility were as follows: A: 0.6698, B: 0.8068, C: –0.2767, D: 0.2071, and E: 0.7695. The correlation coefficient for all facilities was 0.5634, indicating a weak correlation. The coefficients of determination for the regression analysis to predict the compound malodor for facilities A, B, and E were 0.4093, 0.6316, and 0.5695, respectively, which validated the results of the correlation analysis. These values improved to 0.8394, 0.6941, and 0.7476 in the multiple regression analysis with the VOC analysis results added as independent variables. Therefore, it is expected that THC measurement that considers the characteristics of the facility can be used to establish a systematic odor management plan.

Due to the onset of urbanization worldwide, there is an increasing demand for improving the quality of the urban environment. Odor in wastewater collection systems (WCSs) can interfere with the comfortable and safe living conditions of citizens. Additionally, it can cause economic losses, such as the corrosion of wastewater collection facilities. In this paper, the mechanism of odor generation in WCSs was summarized, and the odor concentrations and sulfide generation rates measured in domestic and foreign WCSs were comprehensively analyzed to review the characteristics of odor emission in WCSs. The complex odor intensity (dilution-tothreshold value) measured in combined domestic sewers ranged from 10 to 10,000, with a median of 100. The odorous compound with the highest contribution to complex odor intensity was hydrogen sulfide, which was the odor most frequently detected at the highest concentrations in most WCSs (its median and mean concentrations were 378.0 ppb and 3,771.2 ppb, respectively). The odor emission properties in the WCSs in Australia and Finland were similar to those of South Korea, with the median and mean concentrations of hydrogen sulfide being 1,927.5 ppb and 12,306.1 ppb, respectively. The sulfide generation rates measured in domestic and foreign WCSs ranged from 0.003 to 0.220 g m–2 h–1. In addition, the key factors affecting sulfide generation were sulfate and organic matter concentrations, pH, temperature, flow rate (retention time), dissolved oxygen concentration, and electron acceptor concentrations other than sulfate. To control odor in WCSs, various methods have been proposed to improve their anaerobic environment. These include sucking outside air into the WCSs and improving their hydraulic conditions, such as changing the slope of sewer pipes to minimize sediment deposition. Additionally, periodically removing sediments, which contain a significant amount of organic matters and sulfate-reducing bacteria, is also a useful method for controlling odor in WCSs. Since the odor compounds that contribute the highest odor intensity–and are the most frequently detected–are sulfur-containing odors such as hydrogen sulfide, the control of sulfides is crucial for controlling odor in WCSs. There are chemical control methods for the mitigation of sulfide in WCSs, including air (oxygen) injection and introducing various chemicals, such as alkalis, nitrates, iron salts, and biocides. However, most of the results of odor control using these methods were from laboratory-scale studies. Therefore, additional field-scale experiments should be conducted in WCSs to evaluate the actual effectiveness of various odor control methods. Through these field studies, the optimal conditions for each method to control odor in WCSs can be derived, and the efficiency and economic feasibility of each method can be verified.

The management of pollutant emissions from industrial sites involves various crucial steps, including estimating emission quantities and assessing their impact on surrounding areas. While emissions from point sources, such as exhaust outlets, are relatively easier to manage, emissions from area sources, such as workshops and livestock facilities, are often challenging to measure due to various constraints. To address this issue, this study proposes a method for estimating emissions from area sources by utilizing data collected at site boundaries and applying a reverse modeling approach. Using data from actual livestock facilities, along with reverse modeling results, this study identified a strong correlation between the facility area and the number of livestock raised. Correlation analyses revealed positive relationships between the facility area and the average odor emission rate, as well as between the number of livestock and the average odor emission rate. In addition, the results of reverse modeling confirmed a significant correlation between odor emissions, the number of livestock, and the facility area. Based on these findings, this study developed an odor emission factor for livestock facilities using the number of livestock and the facility area as activity indicators. The odor emission factor is expressed in units of OU/s/pig/m², where “OU” represents odor units, “s” denotes seconds, “pig” corresponds to the number of livestock, and “m²” refers to the total facility area. By multiplying the number of livestock by the facility area, the total odor emission rate (OU/sec) can be calculated. Unlike traditional emission factors that rely solely on the number of livestock, this newly developed factor incorporates all facilities contributing to odor emissions within a livestock operation. This approach allows for the estimation of odor emissions using external measurement data and facility information, even in cases where direct measurements are impractical. The results of this study are expected to be effectively utilized for odor evaluation and management in livestock facilities.

Time-series and spatial analysis of collected odor complaints in Seoul megacity during 2014~2021 were conducted for the characterization of odor complaints emitted from the living environment. The ratio of odor complaints in the environmental complaints was 16.7%, and odor complaints increased 3.3 times from 9,053 cases in 2014 to a maximum of 29,425 cases in 2019. In the time-based evaluation (monthly, daily (day of the week), and hourly variations), the highest number of complaints occurred in June, Monday, and 9:00 AM, respectively. While the lowest number of complaints occurred in December, Sunday, and 3:00 AM, respectively. Among 25 provinces in Seoul megacity, the odor complaints that occurred from 2014 to 2021 were concentrated in Eunpyeonggu. The odor complaints of Seodaemun-gu and Nowon-gu occurred at the highest levels in January-February and June, respectively. Based on the characteristics of odor complaint occurrence according to the above time-series and spatial analyses, more effective odor management and control can be implemented by focusing on those hotspot areas and specific time periods.