Over the past decade, the number of car owners has been steadily rising, leading to a significant increase in the amount of time spent inside cars. As a result, there has been a greater focus placed on the impact of indoor air quality of new cars on drivers and passengers. There has also been a growing awareness among consumers of environmental and health issues such as the odor and indoor air quality of new cars. However, Korea currently only regulates eight compounds according to the indoor air quality management standards for new cars, and there is no test method that reflects the Korean climate. Two domestic gas-powered cars, one imported gas-powered car, and two domestic electric cars were tested under the following conditions: 1) 25oC, 50% RH; 2) 25oC, 50% R.H, solar load (400 ± 50 W/m2); and 3) 60oC, 10% R.H. The results of the 25oC condition met the indoor air quality management standards for new cars by the Ministry of Land, Infrastructure and Transport. Additionally, it was confirmed that the higher the test temperature, the higher the emission of VOCs from the car interior. VOC emissions reached 761.1 μg/m3, and the TVOC concentration was 308,241.4 μg/m3. The odor of new cars increased from a dilution factor of 10 to 208. Two out of five cars exceeded the emission standards of the Ministry of Environment’s Malodor Prevention Act. An odor activity value (OAV) analysis confirmed that acetaldehyde was the highest contributor to odors. The TVOC concentration exceeded the domestic indoor air quality standards for multi-use facilities (1,000 μg/m3). The eight pollutants covered under TVOC management accounted for about 1~6%, while other pollutants were found to account for over 90%. Further studies should expand and review objective indicators that can best represent the indoor air quality of new cars.

Ammonia (NH3) emissions from swine manure are a major contributor to livestock odor and air pollution. In this study, the urease inhibitor Phenyl- Phosphorodiamidate (PPDA) was applied as a preventive control strategy, and its reduction efficiency was evaluated through both chamber simulations and a pilot-scale pig house experiment. The chamber experiment, conducted from March 17 to May 1, 2023, showed that the treatment group receiving both urea and PPDA (P1) exhibited a 53% lower mean NH3 concentration (51.1±15.1 ppm) compared with the urea-only group (U1, 109.0±34.0 ppm; p < 0.001). The maximum concentration was also reduced by 63.8% (245.1 ppm in U1 vs. 88.8 ppm in P1). Dose-dependent tests revealed that reduction efficiency increased with PPDA dosage (1.0 g, 32.3%; 0.5 g, 27.3%; 0.1 g, 21.1%), but gains plateaued beyond 0.5 g, suggesting economic feasibility at intermediate levels. The pilot-scale experiment, conducted in a mechanically ventilated pig house from May 13 to August 2, 2024, confirmed the short-term effectiveness observed in the chamber tests. During the first application period, the treatment group (P5) maintained approximately 50% lower NH3 concentrations than the control group (C2). However, the effect decreased to less than 5% during the second period, and concentrations converged with or exceeded those of the control group during the finishing stage. This decline was attributed to factors such as insufficient slurry mixing, dosage mismatch due to an increase in body weight, and physicochemical changes in the slurry environment. These findings indicate that PPDA effectively suppresses urea hydrolysis and reduces acute NH3 peaks, thereby functioning as a preventive mitigation strategy. Although its long-term efficacy under field-like conditions was limited, optimization of dosage, re-application intervals, and slurry management could enhance performance. Overall, this study demonstrates the potential of PPDA to shift livestock odor management from conventional end-of-pipe approaches toward preventive control strategies, providing a scientific basis for integrated and sustainable odor mitigation.

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 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 comprehensively analyzed the current status of indoor radon management policies and nationwide survey projects in Korea, with the aim of examining the development of the institutional framework, assessing the present management system, and suggesting directions for future improvement. To this end, the analysis focused on the institutional structure, centered on the Indoor Air Quality Control Act, the Ministry of Environment’s Comprehensive Plan for Indoor Air Quality Management, relevant ministries’ management standards, and the designation system for high-radon areas. In addition, major outcomes from national indoor radon surveys conducted since 2008-including nationwide monitoring, intensive surveys in high-radon regions, and investigations of facilities used by vulnerable populations-were reviewed to evaluate their linkage with management policies. The evaluation revealed that domestic radon management policies have achieved visible progress (such as reductions in average concentrations) through the establishment of legal foundations, periodic surveys, and mitigation programs. However, regional disparities in concentrations and high-level exposures in vulnerable facilities remain. These findings indicate that radon management in Korea should move beyond merely complying with numerical standards and incorporate region-specific management strategies alongside a long-term monitoring system.

Airborne bacteria are an important component of atmospheric fine particulate matter (PM2.5), yet the interactions between microbial communities and organic compounds remain poorly characterized. This study investigated the impact of alkane chain length on bacterial dynamics in outdoor PM2.5 using correlation analysis, generalized additive models, and network-based approaches. Among individual alkane species, C30 (n-triacontane) showed a consistent positive association with bacterial concentration in both simple and partial correlation analyses, whereas C20 (n-eicosane) and C24 (n-tetracosane) exhibited significant negative associations only after controlling for collinearity among alkanes. Grouped alkane classes (C20–C24, C25–C29, C30– C35) did not show statistically significant nonlinear effects on bacterial concentration in models using the full dataset. However, temperature demonstrated a strong nonlinear effect and acted as a modifier of alkane-bacteria relationships. Stratified generalized additive models revealed that under high-temperature conditions (≥ 14oC), all three alkane groups showed significant and localized nonlinear associations with bacterial concentration, with the strongest positive response observed for C30–C35 (p = 0.0011). Network analysis indicated that mid-chain alkanes (C20–C25) were positively linked to metabolically versatile genera such as Pseudomonas, Caldalkalibacillus, Pseudarthrobacter, Pigmentiphaga, and Janthinobacterium, whereas long-chain alkanes (C26–C35) were negatively associated with genera including Methylosinus, Pelomonas, and Pedomicrobium. These results suggest that alkane chain length acts as an ecological filter structuring bacterial communities present in PM2.5 and that hightemperature conditions (≥ 14oC) enhance these interactions by altering alkane phase behavior and particle stability. Understanding these coupled chemical and biological processes is therefore critical for anticipating future changes in air quality and emerging health risks.

This study proposes a novel diagnostic methodology combining mobile measurement using selected ion flow tube mass spectrometry (SIFT-MS) and explainable artificial intelligence (XAI) to effectively monitor and diagnose localized highozone (O3) events in industrial complexes. The methodology was applied to a highconcentration ozone episode (maximum 94.0 ppb) observed in the Hwaseong Bio Valley, an industrial complex. A nonlinear regression model based on the Random Forest algorithm was developed to quantify the contribution of precursor species. Specifically, to precisely diagnose the individual contributions of volatile organic compounds (VOCs), which are critical determinants of ozone formation, a modeling approach centered on VOCs was employed by excluding inorganic precursors (NOx). Contrary to traditional ozone formation potential (OFP) analysis, which prioritized high-reactivity alkenes such as propene, the AI model identified cyclohexane and butanone (MEK) as the key drivers positively correlated with ozone concentration fluctuations. This discrepancy is attributed to the “abundance effect,” where atmospheric partial pressures of organic solvents, extensively emitted from pharmaceutical and bio-industrial processes, overwhelm the differences in chemical reactivity of individual species. The findings suggest that AI techniques can interpret the nonlinearity of complex photochemical reactions based on observational data, serving as a complementary site-specific diagnostic tool to existing property-based assessments (e.g., MIR). Consequently, future air quality policies should shift from uniform regulations to a more targeted approach, utilizing the proposed methodology to establish precise emission tracking and management systems.

This study investigates the emission characteristics of volatile organic compounds (VOCs) and aldehydes (HCHO) from ventilation air filters manufactured using two different bonding methods: chemical bonding and thermal bonding. Small-chamber tests were conducted in accordance with KS ISO 16000-9:2006 to quantitatively compare the hazardous substance emissions of five filter specimens with varying bonding mechanisms and exposure surface conditions. The results show that filters produced by thermal bonding exhibited non-detectable (N.D.) levels of toluene, TVOC, and formaldehyde, demonstrating that this manufacturing method inherently minimizes chemical emissions by avoiding the use of adhesives. In contrast, filters manufactured through chemical bonding released formaldehyde ranging from 0.002 to 0.006 mg/m2·h, which is attributed to residual binder components used during the manufacturing process. Although these levels meet the highest grade criteria (≤ 0.008 mg/m2·h) in the Korean eco-friendly building material certification for wallcoverings, meaningful emissions were still observed, and potential grade changes may occur depending on adhesive type, solid content, and coating amount. Furthermore, this study found that differences in the exposed surface (single-sided vs. double-sided) significantly influenced calculated emission rates. This result revealed the limitations of applying building-material-based chamber test methods to filter materials through which air directly flows. These findings highlight the necessity of developing dedicated testing standards for ventilation filters, including appropriate exposure definitions. Overall, this research confirms that ventilation filters should be incorporated into institutional management frameworks alongside conventional building finishing materials, given their direct influence on indoor air quality.

This study quantitatively evaluated the real-world performance of an IoTbased, context-aware mobile air purification system. Additionally, this system is proposed as a practical alternative to conventional stationary purifiers, overcoming their spatial limitations. To analyze concentration variations, removal efficiency, and air cleaning ratio (ACR) for PM2.5, PM10, and HCHO, three scenarios were tested: S1 (natural ventilation), S2 (stationary purifier), and S3 (IoT-based mobile air purification system). The mobile system (S3) achieved a 1.6-fold higher removal efficiency for PM2.5 compared with the stationary purifier (S2) and reduced the ACR to below 0.4 within 30 minutes after high-concentration events. In contrast, stationary purifiers required approximately 333 minutes to reach background levels (17.11 μg/m3), revealing about a 10-fold difference in cleaning speed. Monte Carlo simulations confirmed the consistent superiority of S3 for both particulate and gaseous pollutants, with HCHO concentrations 36.7% lower (90th percentile) than under S2. According to the health risk assessment, the asthma hospitalization rate decreased by over 40%, the HQ for PM2.5 decreased from 1.1 (S1) to 0.64 (S3), and the ECR for HCHO was 0.62 times that of S2. These findings highlight that spatial responsiveness and mobility, along with filter capacity, are key determinants of air purification performance. In conclusion, the mobile air purifier effectively overcomes the structural constraints of stationary devices and establishes a new paradigm for realtime, adaptive indoor air quality management that helps safeguard occupant health.

This study experimentally evaluated the filter lifespan extension achieved by a retractable, built-in air purification system equipped with a self-cleaning rotating filter. Conventional fixed-type air purifiers commonly experience a rapid increase in pressure drop and non-uniform airflow distribution as dust accumulates on the filter surface, leading to degradation in long-term purification performance. To overcome these limitations, the proposed system incorporates a retractable filter module and a rotational dust-removal mechanism designed to maintain stable airflow and reduce particulate loading during extended operation. Experiments were carried out in a controlled 30 m3 residential-scale test chamber to compare filtration performance, pressure-drop characteristics, and particle removal efficiency between the self-cleaning retractable system and a conventional fixed-depth configuration. The results indicate that the rotating self-cleaning mode reduced pressure drop by up to 18.5% and improved PM2.5 removal efficiency by approximately 12.7% relative to fixed operation. Increasing the filter protrusion depth further enhanced airflow uniformity and expanded the clean-air coverage area, thereby delaying the onset of filter saturation. Overall, the findings demonstrate that the proposed retractable, built-in air purification system effectively suppresses pressure-drop rise, maintains purification efficiency, and extends usable filter life. These results confirm the system’s practical applicability for residential indoor-air-quality management and lay the foundation for future optimization and commercialization.

As people spend most of their time indoors, managing indoor air quality (IAQ) has become critical. However, current standard test methods for paints using undiluted solutions do not reflect actual construction practices where thinners are added. This study aims to investigate the effects of dilution ratios on TVOC and formaldehyde (HCHO) emissions. Ten types of paints were tested using a small chamber method under undiluted (Org.) and diluted (Dil. 1, Dil. 2) conditions based on manufacturers’ specifications. The results showed that HCHO emissions were not significantly affected by dilution. However, TVOC emission patterns were categorized into four groups. Notably, some oil-based paints showed an initial suppression followed by a reversal phenomenon where emissions exceeded the original solution after three days. These findings suggest that the current test standards may underestimate the actual risk, highlighting the need to revise the regulations to reflect real-use dilution conditions.

The COVID-19 pandemic has highlighted the importance of indoor environmental management in facilities vulnerable to infection, such as long-term care facilities, where residents remain indoors for extended periods. In light of this, this study investigated the architectural characteristics and ventilation conditions of long-term care facilities in South Korea using a nationwide survey. An online survey targeting 12,425 facilities was conducted in April 2022, and valid responses from 5,550 facilities were analyzed. The survey examined building layouts, ventilation methods, mechanical ventilation systems, air purifier use, and ventilation operation and maintenance. The results showed that numerous facilities had architectural configurations unfavorable for natural ventilation, including a high proportion of double-loaded corridor layouts. Mechanical ventilation systems were installed in only 41.4% of facilities, whereas air purifiers were present in 72.3%, indicating a reliance on air cleaning rather than outdoor air ventilation. Although ventilation managers and regular inspections were commonly reported, formal operation and maintenance manuals were less prevalent. These findings indicate structural and system-level limitations in achieving stable ventilation performance in long-term care facilities. Additionally, they provide baseline data to support improvements in ventilation strategies and policies for infection-vulnerable facilities.

This study examined the applicability of the ATP bioluminescence assay for the efficient screening of paper-based records requiring disinfection for preservation. For the investigation, microbial contamination was measured on the surfaces of six types of paper-based records (fine-print paper, medium-print paper, ground paper, newsprint paper, practice paper, and tracing paper) using two ATP luminometers (Lumitester SMART PD-30 and 3MTM Clean-TraceTM LM1) at the National Archives of Korea. Among the six paper-based record types, medium-quality paper, tracing paper, and fineprint paper exhibited the highest contamination levels, confirming varying degrees of vulnerability based on the materials. RLU values were measured in the records of old drawings from the year 1111 and in records from the year 1831. RLU values were also present in the records from the years 1904 and 1911. The records from the year 1922 showed high RLU values of 3,639 and 2,662 in both ATP luminometers, indicating a very high level of microbial contamination. The RLU of the drawings stored in NF501 storage ranged from 7 to 57 (LM1 measurement) and 64 to 524 (PD-30 measurement). Overall, measurements of records on paper materials that had not been disinfected showed microbial contamination levels ranging from low to very high, and these materials consisted of records dating from 1900 to 2003. Furthermore, the Lumitester SMART PD-30 luminometer yielded significantly higher RLU values than the 3MTM Clean-TraceTM LM luminometer, demonstrating a substantial discrepancy between the two devices. Therefore, to ensure the reliability and efficiency of the disinfection process, it is necessary to standardize the use of ATP-specific detection methods.

Microorganisms such as pathogens from humans, pets, and plants, as well as bacteria, fungi, and viruses, can cause damage in indoor environments, leading to infections and allergies. Additionally, the presence of indoor microorganisms can result in food contamination and economic damage, along with odors, corrosion, discoloration, and damage to facilities, equipment, and buildings. Therefore, a hygienic approach that includes research on microorganisms in indoor environments should be taken for their management. However, past approaches to indoor microorganism management have been limited to measuring the concentration of airborne bacteria and mold as stipulated in the Ministry of Environment’s Indoor Air Quality Act. Due to the COVID-19 pandemic, interest in microorganisms in indoor environments has been on the rise, along with demands to mitigate the damage they create. Because microorganisms have varying degrees of impact on the environment and organisms, they are classified by risk level and require secure research facilities tailored to target biosafety levels. However, there is a lack of awareness of the application of facilities and biosafety to study indoor microorganisms existing in indoor environments. Accordingly, in this study, both domestic and international biosafety regulations were reviewed, the harmfulness of indoor microorganisms was evaluated, and considerations for handling indoor microorganisms in domestic universities, companies, and public institutions were proposed.

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.