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.

This study was conducted to solve the problem of the existing odor management method taking a long time to analyze samples. Using real-time air quality measurement equipment, 17 designated odor substances were measured three times at a business site causing odor complaints. As a result, three substances, hydrogen sulfide, trimethylamine, and methyl mercaptan, were measured at higher levels than the site boundary emission standards inside the business site. In the case of trimethylamine, it was measured about 500 times higher than Odor Threshold Values, and was estimated to be the substance causing the odor. Through an inspection of the business site, improvements were instructed to be made to the wastewater treatment process, which is the emission facility where trimethylamine is generated. Subsequent measurement results showed that designated odor substances were measured within the emission standards at all locations, and it was determined that efficient management of odorgenerating businesses would be possible if Selected Ion Flow tube-Mass Spectrometry was utilized.

This study developed and tested a pilot-scale biowindow for simultaneous removal of odor and methane from landfills. The test was conducted in a sanitary landfill site during the summer season (July and August). The average temperature inside the biowindow was 5°C higher than the average air temperature, rising to 37–48oC when the outdoor temperature was very hot. The complex odor removal rate (based on the dilution-to-threshold value) in the biowindow during the summer was 91.3- 98.8% (with an average of 96.2±4.2%). The average concentration of hydrogen sulfide was 3,024.9±805.8 ppb, and its concentration was found to be the highest among 22 odorous compounds. The removal efficiencies of hydrogen sulfide and methyl mercaptan were 89.1% and 83.2%, respectively. The removal of dimethyl sulfide was 17.7%, and no ammonia removal was observed. Additionally, the removal efficiencies of toluene and xylene were 85.2% and 72.5%, respectively. Although the initial methane removal was low (24.9%), the methane removal performance improved to 53.7–75.6% after the 11th day of operation. These results demonstrate that the odor and methane removal performance of the pilot-scale biowindow was relatively stable even when the internal temperature of the biowindow rose above 40oC in the summer. Since the main microorganisms responsible for decomposing odor and methane are replaced by thermotolerant or thermophilic microorganisms, and high community diversity is maintained, odor and methane in the biowindow could be stably removed even under high-temperature conditions.

In this study, hybrid devices were developed to simultaneously remove odor and particulate matter (PM) emitted during meat grilling, and their performance was evaluated. A ceramic filter system and surfactant microbubble plasma system were used to reduce particulate matter. For odor reduction, an electro-oxidation system, an ozone-active catalytic oxidation system, and a multi-adsorption filter system were used. By combining the above particulate matter reduction and odor reduction devices, the reduction efficiency of odor and particulate matter generated during meat grilling was analyzed. As a result, most of the six combined device conditions showed a reduction efficiency of more than 90% for particulate matter. The combined odor also showed a high reduction efficiency of less than 200 times the emission concentration standard. This study also evaluated 22 types of odorous substances, of which ammonia (NH3) and hydrogen sulfide (H2S) showed removal efficiencies of more than 99%. Therefore, it is expected that the combination of these technologies can be used and applied directly to the sites where meat grilling restaurants are located to effectively contribute to the simultaneous reduction of particulate matter and odor.

This paper aims to review the odor removal performance and operating parameters of pilot and full-scale chemical scrubbers, bioscrubbers, biofilters, and biotrickling filters for odor control in wastewater treatment plants. Based on the performance of full-scale facilities installed in wastewater treatment plants, empty-bed residence times were the shortest for bioscrubbers (7.5±2.5s), followed by chemical scrubbers (20±8.1s), biotrickling filters (22.2±26.2s), and biofilters (48±30s). The removal efficiencies of complex odors by biofilters, biotrickling filters, bioscrubbers, and chemical scrubbers were 97.7±1.9%, 87.7±15.6%, 89.0±9.0%, and 70.0%, respectively. The investment cost was the lowest for biofilters, followed by biotrickling filters, bioscrubbers, and chemical scrubbers. In addition, the operating costs of these deodorization technologies were in the following order: biofilters < bioscrubbers and biotrickling filters < chemical scrubbers. However, most studies on odor control for wastewater treatment processes have been conducted on a laboratory scale with model odors (single odorous compound or mixtures of 2-3 odorous compounds). Therefore, field research to develop deodorization technologies for wastewater treatment plants should be more actively conducted to accumulate data for the design and operation of full-scale deodorizing systems.

The odors emitted from wastewater treatment plants are not only a health and hygiene problem, but can also lead to complaints from residents and have wider social ramifications such as bringing about falling property values in the surrounding area. In this paper, based on the data measured at domestic and overseas wastewater treatment facilities, the concentrations of complex odors and odorous compounds were compared for each treatment/process: primary treatment, secondary treatment, and sludge treatment processes. Odor compounds that contribute greatly to complex odors were summarized for each process. In addition, the characteristics of odor wheels for each wastewater treatment process, which provide both chemical and olfactory information regarding odors, were reviewed. For domestic wastewater treatment facilities, the complex odor concentrations (unit, dilution factor) of the primary and secondary treatment processes were 4.5-100,000 (median, 32.1) and 2.5-30,000 (median, 10.7), respectively. However, the complex odor concentrations in the sludge treatment process were 3.0-100,000 (median, 118.7), which was more than three times higher than that in the wastewater treatment process. In the wastewater treatment process, those odor compounds making the greatest contributions to complex odors were sulfur-containing compounds such as hydrogen sulfide, dimethyl sulfide, and dimethyl disulfide DMS. In order to properly manage odors from wastewater treatment plants and minimize their impact, it is important to understand the status of odor emissions. Therefore, the compositions and concentrations of odors from wastewater treatment processes and odor wheel information, which are reviewed in this paper, are used to evaluate the potential risk of odor from wastewater treatment facilities in order to derive strategies to minimize odor emissions. Moreover, the information can be usefully used to introduce the best available technology to reduce odors emitted from wastewater treatment facilities.

This study evaluated the effectiveness of odor reduction when spraying inside the Bio-curtain (hereinafter referred to as curtain) according to the exhaust fan operating rate. Spraying is a main factor affecting the ability to odor reduction of curtains. The curtain (total area: 37.9m3) was constructed with two layers of light-shielding screens stretched over a rectangular parallelepiped structure installed around an exhaust fan (630 mm) on the side wall of a pig barn. Air samples for odor analysis were collected from inside the pig barn and outside the curtain. The main odorous compounds such as volatile fatty acids, phenols, indoles, and ammonia were measured. The odor reduction effectiveness was evaluated by total odor activity values (TOAVs) summed to the odor activity values of each odorous compounds. Depending on the exhaust fan operating rate, the reduced rate of TOAVs gradually decreased to the range between 15.67% and 68.80%. Because the contact time between the spraying liquid and the air velocity of the exhaust fan becomes shorter (or there is a reduction in liquid to gas flow ratio) as the exhaust fan operating rate increases. The results of this study can be used as basic data for research into spraying conditions to improve the odor reduction effectiveness of curtains.

Odor is a type of air pollution where irritating substances enter through the olfactory system, causing discomfort. At present, the government is formulating various measures and policies to address this type of pollution. This paper seeks to analyze major research cases from both domestic and overseas settings in relation to odor management. In addition, it reviews the potential of addressing environmental issues using a living lab approach in conjunction with community mapping and citizen science. For example, in one domestic case, the Magok smart city living lab project, citizens’ data on community mapping of odor were collected for analysis using artificial intelligence (AI) to derive results. Additionally, in an overseas case in California, citizens directly participated in monitoring air quality using the Community-based monitoring (CBM) method, and both CBM and existing methods were used to assess the level of pollutants for effective data collection. In both of these cases, the potential to address environmental issues was seen to manifest through the development of citizens’ determination and ability to independently solve local problems. However, there are still problems in implementing citizen science, such as the lack of infrastructure and resources available, issues with data collection methodology, questions of objectivity regarding collected data, and concerns about sustainability and expertise in relation to civic participation. Addressing these problems would require an institutional foundation and systematic civic education. This study highlights the potential of addressing environmental problems inherent in the living lab system based on citizen science by analyzing two cases. In addition, this study suggests that if systematic civic education measures are introduced to address issues within existing citizen science research approaches, such measures would be valuable within the educational living lab framework in that they would become effective in tackling not only environmental problems but also social problems as well.

This review paper aimed to comprehensively assess the ventilation methods and ventilation rates of livestock sheds, various livestock odor mitigation technologies, and the design flow rate of odor mitigation devices. The most efficient ventilation method for livestock odor control was found to be mechanical ventilation. When livestock odor is at its most severe during summer, ventilation systems are operated at the maximum ventilation rate, which is 5-25 times higher than the ventilation rate in winter. Therefore, the mitigation facilities of livestock odor must be designed while considering the maximum ventilation rate. There is a significant amount of research data on various livestock odor control technologies using various physical, chemical, biological, and complex technologies applied to livestock farms. Biofiltration and photocatalytic oxidation are considered the most promising methods due to their cost-effectiveness and simplicity. Biofiltration is effective for removing hydrophilic odors, but requires improvement for the efficient removal of hydrophobic odors and the control of accumulated excess biomass. The advantages of the photocatalytic oxidation method include its excellent hydrogen sulfide and ammonia removal rates and relatively low ozone emissions. However, it requires technology to reduce nitrous oxide emissions. Investment in installing and operating these odor mitigation technologies is only realistic for large-sized farms. Therefore, it is imperative for small and medium-sized livestock farms to develop odor mitigation technology that is inexpensive and has low installation, operation, and maintenance costs.