Low-cost particulate matter (PM) sensors based on the light scattering principle measure the concentration of particles by the change of scattering intensity after light is irradiated onto the particles. It has been reported that when the relative humidity is high, water vapor may cause the expansion of airborne particles and affect the accuracy of the light scattering method for PM measurement, but it has also been shown that the effect of humidity is not significant or even negligible. Therefore, to determine the effect of humidity on the Plantower PMS7003 light scattering sensor, in this study, a BAM1020 (Beta Attenuation Monitoring) was installed alongside to continuously monitor the ambient atmospheric PM concentration for approximately four weeks. The sensors collected data at 10-minute intervals, resulting in a 1-hour average for comparative analysis. To accurately measure humidity, the performance of the Arduino + DHT22 humidity sensor was also pre-evaluated using a series of saturated salt solutions. The humidity was grouped into five intervals and analyzed by visual analysis. The results confirmed that there was no significant correlation between PM2.5 differences and humidity, which were randomly and uniformly distributed around the mean. However, since in the very low and high concentration ranges based on the beta-ray monitor measurements, the difference between the light scattering sensor PM10 measurement and the reference value is much larger than the difference between the PM2.5 and the reference value., there is an additional need to investigate the appropriate correction method for dust season or PM10. The results show that the outcomes of the light scattering sensor are more influenced by particle size and concentration than by humidity.

In this study, the removal performance of high-concentration H2S and complex odors was evaluated for bio-filters installed in sewage treatment plants and manure treatment plants. The amount of odor generation according to temperature was found to be higher in summer than in spring. It was found that the longer the empty bed retention time of the bio-filter, the higher the odor removal efficiency. Therefore, in order to effectively remove odors, it is necessary to maintain a sufficiently long residence time when designing a bio-filter. In addition, a case in which a bio-filter and a wet pre-treatment system were combined to remove high-concentration odors was studied. The result showed that the wet pre-treatment was effective in removing high-concentration odors. In particular, most of the hydrogen sulfide could be adequately removed by wet pre-treatment.

Four types of metal oxide semiconductor gas sensor arrays were used to observe the aroma and spoilage odor emitted during the ripening process of plum & banana fruits. All gas sensors showed a high correlation (R=0.82~0.90) with the olfactory. The TGS 2603 sensor showed a high correlation of 0.90 between the odor generated and sensory perception of smell in the process of ripening and decaying fruits. In addition, it showed a very high correlation of 0.91 with the decay rate of the plum sample, and the significance probability through one-way ANOVA was also less than 0.05, which confirmed it as an optimal gas sensor (TGS 2603). Principal component analysis was performed using all the data. The cumulative variability was 99.54%, which could be explained only by two principal components, and the first principal component was 95.11%, which was related to the freshness of the fruit. It was analyzed as fresh fruit in the negative(-) direction and decayed fruit in the positive(+) direction.

This study was carried out in order to help establish a continuous efficiency test method to evaluate the performance of chemical odorants. We designed a continuous efficiency test device, and conducted several experiments during 240 mins with D.W. and two chemical deodorants for several specified substances, and a complex odor compound. Based on the results, it was confirmed that the deocorant test only for ammonia and amine could yield no useful outcome because the solubility of the two compounds was very high. Henceforth, simultaneous tests for sulfides, mercaptans, aldehydes, and so on, shoud be conducted in order to ascertain the accurate deodorant performance results. It is also clear that the concentration of target compounds and reaction time are very important for the purposes of accurate deodorant tests. In addition, information about the absorption efficiency with regard to complex odor compound such as DMS+DMDS may be important and the results based on air dilution olfactory method should be provided. It is believed that this study can make a contribution to formulating the correct standards regarding the testing of deodorants and the application of such tests.

n-Butanol is used to assess how odor intensity correction affects judges’ evaluation of the odor intensity based on the concentration. The odor intensity correction effect is verified by using three types of test solutions which are used for the selection of judges based on their concentration levels. The correction effect is statistically analyzed according to gender, odorant type, and concentration on the group and individual level. The result shows that n- Butanol correction affects the odor intensity evaluation for three odorants in different ways. In most cases, n- Butanol correction increases the panelists' sensitivity to the odor intensity change, and results to be close to the theoretical value. The female panelists can more accurately evaluate the sourness intensity of acetic acid after n- Butanol correction. All panelists regardless of gender can more accurately evaluate the fishiness intensity of trimethylamine after n-Butanol correction. For evaluating the caramel smell intensity of methylcyclopentenolone, a full panel without n-Butanol correction is recommended. Therefore, n-Butanol correction should be included in the process of judge selection and the odor intensity assessment.

Since the implementation of the Odor Prevention Act in 2005, the number of odor complaints has continuously increased due to the increased interest in the living environment. The current odor control means is a concentrationbased method for the source of odor. That is why there is a difference between the odor sensitivity and the result of the odor measurement in the odor damage area. The government is considering the introduction of the grid method, which is the odor management method of Germany, as the method of odor investigation in the odor damage area in the second comprehensive Odor Prevention Policy (2019-2028). The grid method is receptor-based odor measurement method that investigators use to judge odors in the field, task that expensive and requires substantial manpower and time. To study an odor measurement method that is suitable for domestic conditions, this study compared the correlation between results based on the odor frequency concept grid method around the livestock facilities and the result of ammonia concentration measured by passive air sampler. The correlation coefficient (R) that is between the frequency of odor per spot for the entire odor and the ammonia concentration that was measured by passive air sampler was 0.65 which is relatively good. Among the entire odor detected by the grid method, the correlation coefficient (R) between the odor frequency selected only for livestock odor and the ammonia concentration was significantly increased to 0.80. In addition, the correlation between odor exposure (ECPexist) and the ammonia concentration for the overall odor was 0.81 (linear) and 0.86 (index). If only the livestock odors were selected, the correlation between odor exposure and the ammonia concentration was very high at 0.96 (linear) and 0.95 (index).

This study is a summary of the complex odor proficiency testing method using the air dilution sensory method conducted for the last 7 years. Results of the homogeneity and stability test were obtained from the measurement of the standard sample for identifying the range of measurable concentration so that the complex odor proficiency testing method was established through processing the manufactured standard sample and distribution method. Standard samples were prepared using a large Teflon bag after being homogeneously mixed inside a Teflon bag. Also, a distributing container was selected with a polyester aluminum bag in order to avoid samples of the best condition from being contaminated during transport as well as being exposed to invasive odor from a sampling bag. Test results revealed that the mixture of toluene and m-Xylene was most appropriate for this proficiency testing method to the homogeneity and stability of the testing method. In addition, DMS and DMDS were the optimized samples at the outlet area. As a result, the standard method was established to address the analysis quality management to the mixed odor inspection agencies in Korea.

본 연구에서는 현행 악취공정시험방법에 나타나있는 공기희석 관능법을 사용하여 물질농도와 희석배수와의 관계를 살펴보기 위해 프로피온산, 뷰틸산, 발레르산, i-발레르산 및 i-뷰틸알코올에 대한 물질농도와 희석배수를 측정하였다. 또한 상관관계식을 이용하여 지정악취물질의 농도 규제치의 적정성을 검토하였다. 1. 판정인에 의해 측정된 대상물질의 물질농도와 희석배수의 상관관계는 식 Log C = Af·Log D + 0.5에 의해 적절하게 나타났으며, 총 22종의 지정 악취물질별 상관관계식의 기울기 값의 범위는 0.9023~1.2012으로 이소발레르알데하이드가 가장 작고, 뷰틸알데하이드가 가장 큰 것으로 나타났다. 2. 물질별 관계식으로부터 산출된 희석배수 15와 20에 해당되는 물질농도와 최소감지농도와의 비를 구한 결과, 각 물질의 농도비가 희석배수 15 및 20과 유사한 수치를 나타내 물질별 관계식이 의미가 있는 것으로 추정되었다. 3. 물질별 관계식으로부터 산출된 희석배수 15와 20에 해당되는 물질농도와 현행 물질농도 기준치와 의 비교를 통하여 기준치의 적정 수준 여부를 검토 해본 결과, 프로피온산과 뷰틸산의 경우는 기준치가 상대적으로 낮게 설정된 것으로 판단되며, 발레르산, 이소발레르산과 뷰틸알코올의 경우 물질농도 기준치가 적정 수준인 것으로 추정된다. 본 연구결과는 현행 악취방지법의 부지경계선에서 복합악취 농도 규제기준에 대한 개선방안 및 지정악취 물질들의 물질농도와 악취강도, 희석배수간의 상관관계 및 특성연구 등의 기반 자료로 사용될 수 있을 것이다.

In this study, the homogeneity and stability of standard samples for proficiency testing in indoor air quality within the country (formaldehyde, benzene, toluene, ethylbenzene, p-xylene, styrene, TVOC) were evaluated. The procedures and statistical analysis methods applied in ISO/IEC 13528 (2009) and KS A ISO Guide 35 (2005) were applied as evaluation methods. The homogeneity evaluation was a statistical analysis of repeated measurements of each of the 11 ports and between the 11 ports concentration data. As a result, the coefficient of variation (CV) was within the range of 1.9%~5.9%. The difference between the ports was found to be insignificant and met the statistical standard specified in KS Q ISO 13528. The stability evaluation was assessed by the change in concentration over the long-term stability of the standard samples stored for 90 days. The coefficient of variation (CV), which was within the range of 2.6%~9.0%, exhibited changes in the concentration of the long-term stored standard samples. However, the results satisfy the statistical standard specified in KS A ISO Guide 35. Overall, there is no significant difference between the homogeneity of the standard samples by the port and the stability of the long-term stored samples. Therefore, it is considered to be an appropriate method to supply standard samples in an indoor air quality proficiency test.

The changes in the aroma and spoilage odor emitted from eleven ‘Hongro’ apples during ten weeks’ storage were investigated using six types of metal oxide semiconductor gas sensor arrays. The gas sensors used in the evaluation were sensitive to apple-emitted aroma or spoilage odor, and a high reproducibility of 5% relative standard deviation or less was confirmed. Significantly, the change in apple-emitted aroma or spoilage odor was easily distinguished by the optimal gas sensor and a significant correlation (r=0.992) between decay rate and sensitivity change was observed. The results of a principal component analysis of the signal patterns obtained by data standardization using the optimal gas sensor showed a clear classification between decayed sampler groups and undecayed sampler groups.

This study was designed to assess the odor characteristics of paprika with metal oxide gas sensors. Non-decayed paprika and decayed paprika were assessed by sensor array system comprising 10 kinds of sensors. Three representative sensors were selected from among the 10. Selection was based on a correlation analysis between sensors from the results of the sensor array assessment on non-decayed paprika. It was found that the odor variation characteristics of paprika can be assessed by metal oxide gas sensors and that the odor variation characteristics of paprika are different depending on the type of gas sensors. The odor characteristics of paprika were different according to the color, the presence or absence of decay, the location of decay, the type of sensor, and the passage of time. Regardless of decay, the sensor response value of orange paprika was the highest, with the 2611 sensor yielding the highest response value. The SB-AQ1 sensor could not identify the difference in odor characteristics depending on the location of decay, while detection was possible by both SB-41 and 2611 sensors.

The gas sensor sensitivity value of three methods (simple application method, vaporization method, and chamber method) were compared in order to establish a method for the measurement of liquid odor substances. In order to select the representative sensors from among the 16 sensors constituting the gas sensor array, cluster analysis, regression analysis, and correlation analysis were performed. Sensors with excellent correlation in terms of reactivity were selected as representative sensors of each measurement method. As a result, it was shown that the reactivity and the correlation increased in the order of simple application method < vaporization method < chamber method. Through a variance analysis using the sensitivity values of selected representative sensors, it was shown that the simple application method had statistical significance at the level of 99.9% (p<0.001) in three of the representative sensors in four clustering groups. The vaporization method and the chamber method showed statistical significance at a level of 99.9% (p<0.001) for all representative sensors in each clustering group. If the reactivity were improved by controlling the sensitivity of the sensor, the simple application method and vaporization method could also be used as a method of measuring the liquid material with gas sensor array.

This study aims to understand the correlation between odor intensity and dilution factor using the Air Dilution Olfactory Method, which is suggested in the Standard Method of Odor Compounds, by measuring odor intensity and dilution factor for fatty acids and i-butyl alcohol. For the measurement, 18 panel members were selected through a panel test, and odor intensity and dilution factor by substance produced from the selected panel were estimated. The estimation showed that the correlation of odor intensity with dilution factor for a fatty acids and i-butyl alcohol can be reasonably expressed by the equation I = A·log D + 0.5 (I : odor Intensity, D : dilution factor, A : material constant). The material constant was in order of propionic acid 2.0709, n-butyric acid 1.6006, n-valeric acid 1.3369, i-valeric acid 1.182, i-butyl alcohol 1.4326. The geometric average of increased dilution factor for the 5 compounds is about 4.8 time, 3.0 time for propionic acid and 7.0 tme for i-valeric acid due to odor intensity 1 increasing. It is suggested that the result of this study could be used as a base data for research on measures to improve the regulation standards for complex odor concentrations at a boundary sites in operation.

The correlation analysis between odor sensor and air dilution olfactometry method with odor emission facilities was performed for the real-time evaluation of odor emitted from the 13 facilities. The total correlation was less significant for all facilities due to various emission characteristics of odor. The correlation for the individual facility, however, showed a higher correlation coefficient (R=0.7371~0.9897). Especially, the strong correlation (above 0.9) was observed for the industry type with the odor characteristics like tobacco, styrofoam, acetic acid, and burning smell. The repeated odor measurements using the odor sensor showed good reproducibility with the mean relative standard deviation of 5.06%. The odor sensor could be useful tools for identifying and evaluating odor with an olfactometry in field, if the use and proofreading of the odor sensor are improved by a standardized method.

The purpose of this study is to evaluate the performance of a tube and badge type NO2 passive air sampler. The principle of the method is a colorimetric reaction of NO2 with N-1-naphthylethylendiamine under acidic conditions. The sampling rates for the tube and badge type passive air samplers was determined 12.3 ± 4.4 mL/min and 27.3 ± 4.9 mL/min, respectively, as obtained from the slope of the linear correlation between the NO2 mass collected by the passive air sampler and the NO2 concentration with the NO2 analyzer. The tube and badge type passive air sampler were moderately correlated with a correlation coefficient of 0.9112. The measurement for the precision and accuracy of the passive air sampling was carried out with duplicate measurement of passive air samplers. The passive air sampler had good precision and accuracy for measuring NO2 in atmosphere. A good correlation was observed between the passive air sampler and the NO2 analyzer with a coefficient of determination of 0.9153 (tube type) and 0.9514 (badge type). This passive air sampler would be suitable for the NO2 concentration monitoring in atmosphere.

This study aims to evaluate the relationship between concentration and odor intensity using the odor sensory method for 4 types of fatty acid compounds and i-butyl alcohol. For the measurement, 18 panelists were selected based on several criteria through a panel test. Panelists chosen for their closely similar sensitivities provided more reproducible values. The estimation showed that the correlation of the concentration with odor intensity for the 5 compounds, including the fatty acid compounds and i-butyl alcohol can be reasonably expressed by the Weber-Fechner equation. Notably the standards regulation fatty acid concentrations are very strict, and the butyl acetate standards are very loose. It is suggested than the results of this study can be used as basic data for research on measures to improve the regulation standards on complex odor concentrations on site boundaries in operation, as well as the correlation between concentration and odor intensity for the designated foul odor substances, and their characteristics.

The purpose of this study is to improve the ammonia (NH3) emission inventory estimation in the domestic CAPSS (Clean Air Policy Support System). Currently, the ammonia emissions rate is obtained by multiplying the activity (number of livestock) by emission factors. The amount of movement and treatment are not considered in the estimation of ammonia emission rates. However, livestock manure is currently moved and treated in accordance with the energy recycling policy. In this study, the new emission estimation method were suggested considering the moving and treatment characteristics of livestock manure. A new ammonia emissions was calculated for Bcity and Y-gun at Chungcheongnam-do province. It was shown that the moving and treatment ratio of ammonia emissions were 4.3% and 8.4%, respectively. Furthermore, this ratio would be increased rapidly with the continuous establishment of large-scale manure treatment facilities.