In this study, the loading rates (or emission rate) and concentrations of air pollutants (ammonia, hydrogen sulfide, carbon dioxide, methane, nitrous oxide, and particulate matter (PM2.5, PM10 and TSP)) emitted from a naturally ventilated dairy facility were analyzed and compared to enable a better understanding that are in close proximity to each other, air pollution status. In general, the pollution patterns should be similar in measurement sites that are in close proximity to each other, and this hypothesis was fundamental to our approach in this study. For the comparison in nearby different sites, monitoring points were located at inside (source site) and outside the dairy building (ambient site), and concentrations and wind velocity were simultaneously monitored in real time. The patterns of PM2.5 emission rate and loading rate were similar in the source site and the ambient site which was consist with the hypothesis, while the PM2.5 mass concentration were not similar in both sites. As well as PM2.5, the emission rates (source site) of gaseous carbon dioxide (CO2) and nitrous oxide (N2O) were highly correlated to their loading rates (ambient site), while the concentrations of CO2 and N2O were not similar. Therefore, wind velocity, which is included in the emission or loading rate, should be simultaneously monitored with the concentration at the same measurement points for better understanding of the air pollution status.
The performance of cascade cycle air-source heat pump has been investigated experimentally. The cascade heat pump cycle consists of high temperature of R134a and low temperature of R410a. We have complementary primary air source heat pump. As a result, we produce the products with the best performance. The rated capacity of heat pump is 25kW and the cold capacity of heat pump is 25kW. The KSCOP_C of colder condition is 2.61 and KSCOP_A of average condition is 2.74 and KSCOP_W of warmer is 2.74.
본 연구에서는 온실 내부의 태양 잉여열과 외부의 공기열을 선택적으로 열원으로 이용함으로써 히트펌프의 성능을 향상시키고, 온실의 환기 지연을 통해 이산화탄소 시용비용을 절감할 수 있는 온실 공조시스템을 개발 하고자 하였다. 본 시스템의 축열 과정은 태양 잉여열을 이용하는 내부순환모드와 외기열을 이용하는 외부순환모드가 온실 내부온도에 따라 자동으로 절환되도록 구성하였으며, 히트펌프가동, 축열모드 절환, 난방 가동을 위한 6개의 온도값을 입력함으로써 축열과 난방이 자동으로 수행되도록 설계하였다. 단동온실을 대상으로 무환기 조건에서 기초시험을 수행한 결과, 태양 잉여열을 이용한 축열은 약 11시부터 시작되어 평균 3시간 30분 정도 유지되었으며, 주간의 온실 내부온도는 환기를 수행하지 않음에도 대부분 약 20~28oC 범위를 유지하였다. 주간 내부순환모드에서 시스템의 난방성능계수는 약 3.35로 야간 외부순환모드의 2.46 및 주간 외부순환모드의 2.67 에 비해 각각 36% 및 25% 향상됨을 확인하였다. 본 시스템의 개선사항으로 태양 잉여열의 효율적 이용을 위해 축열조 관리온도를 상승시킬 수 있는 고효율 히트펌프의 적용이 필요하며, 온실의 무환기 운용에 따른 과습환경의 조성을 방지하고 태양 잉여열 수준이 높은 시기에 온실의 온도상승을 방지하기 위해 강제환기를 운전모드에 추가할 필요가 있는 것으로 판단되었다.
Noise barriers along the road do not only block the traffic noise but also prevent traversing the car exhausts. These barriers may affect air pollution dispersion, leading to increase vertical mixing due to the upwind deflection of air flow caused by the noise barriers. In this study we investigated the air pollution dispersion around multi-noise barriers using commercial software FLUENT. Investigated cases were 8 cases which had from zero to three noise barriers and two emission sources. Simulated results show noise barriers increase the vertical air pollution impact distance larger 1.7~2.1 times than that of no barrier case. It was also found that noise barriers decrease the horizontal air pollution impact distance lower 0.6~0.8 times than that of no barrier case.
In the study, space cooling performance of air source heat pump(ASHP) was evaluated in a pilot house. The ASHP, which provide for floor heating, domestic water heating and space cooling/heating, shows cooling capacity of 14.0 kW, when COP of ASHP was 3.21 based on test performance of KS C 9306. Test results shows that cooling capacity was depended on frequency of the compressor. The variable refrigerant flow rate for cooling were supplied into diverse room by using LEV. The COP at setting room temperature of 26℃ was 6.3% higher than the COP at that of 24℃, when the spending time in operation was decreased as 21.2%.
The night time electric cost is cheaper due to electric supply and demand policy in Korea from 1985. Currently about 900,000 customers are using night time electric heating boilers and this causes shift of peak demand time to night in winter and increase of deficit spending. To solve this problem, replacing night time electric heating boiler by air-source heat pump using night time electricity has been proposed. An air-source heat pump can provide efficient heating equipment especially in a warm climate. For estimating the night time electric heat pump COP(Coefficient of Performance), Korean Standard KS C 9306:2010 and European Standard EN-14511:2004 is available. SCOP(Seasonal COP) using European weather bin data is also calculated. SCOP is not available yet but European Committee for Standardization will establish a standard in the near future. The evaluation result show that the replacing night time electric heating boiler by heat pump can be possible.
The purpose of this study was to assess an alternative method to characterize indoor environmental factors by multiple indoor and outdoor measurements. Using a mass balance model and regression analysis, penetration factor and source strength factor were calculated using multiple indoor and outdoor measurements. This study was performed in 30 selected apartments in Seoul, Asan, and Daegu area which were constructed within 4 years and over 4 years, to measure the concentration of NO2 from July, 2004 to September. The results of this study are as follows. The average concentration of NO2 in Seoul, Asan, and Daegu area in the apartment constructed within 4 years are nitrogen dioxide 48.01㎍/m3 and in the apartment over 4 years are nitrogen dioxide 46.54㎍/m3. Mean ratios of indoor to outdoor NO2 concentrations are Seoul 0.99, Asan 0.83, Daegu 1.18. The deposition constant and the source strength of NO2 were 0.97±0.55 hr-1 and 16.33±12.30 ppb/h, respectively. In conclusion, indoor environmental factors were effectively characterized by this method using multiple indoor and outdoor measurements.
Exposure to nitrogen dioxide (NO2) can produce adverse health effects. Various indoor and outdoor combustion sources make NO2 the most ubiquitous pollutant in the indoor environment. Indoor air quality can be affected by indoor sources, ventilation, decay and outdoor levels. Although technologies exist to measure these factors, direct measurements are often difficult. In the present paper, we used a mass balance model and regression analysis, penetration factor (ventilation rate divided by the sum of ventilation rate and deposition constant) and source strength factor (source strength divided by the sum of ventilation rate and deposition constant) were calculated using multiple indoor and outdoor measurements with 10 houses. Subsequently, mean contributions of indoor and outdoor sources were 28.86% and 81.09%, respectively, suggesting that both indoor and outdoor sources had contributions to indoor concentrations of NO2.
In this study, we investigated the characteristics of Volatile Organic Compounds(VOCs) emission from painting and printing facilities in the Pyeongdong industrial complex in Gwangju. In addition, the objective was to understand the distribution characteristics of VOCs in the ambient air in industrial complexes affected by painting and printing facilities. The painting facility mainly emitted toluene, acetone, butyl acetate, 4-methyl-2-pentanone, ethyl acetate, 1-butanol, methyl ethyl ketone, m,p-xylene, o-xylene, 4-ethyltoluene, ethylbenzene, 3-ethyltoluene, and 1,2,4-trimethylbenzene. The main emission components in printing facilities were methyl ketone, ethyl acetate, acetone, 2-propanol, toluene, heptane, and butyl acetate. Ethyl acetate, toluene, 2-butanone, acetone, butyl acetate, 2-propanol, xylenes, and 4-methyl-2-pentanone were detected in the ambient air of the Pyeongdong industrial complex, consistent with the VOCs emitted by painting and printing facilities. The average concentration of seasonal TVOCs followed an order of winter > fall > spring > summer, whereas the concentrations of daytime and nighttime TVOCs were generally higher at night than those during the day, and the wind speed was greater during the day than it was at night. Based on a factor analysis of VOCs in the ambient air of Pyeongdong industrial complex, it is considered that organic solvents used in coating, printing, and electronics manufacturing facilities, as well as diesel vehicle emissions played a major role.
This study were to simulate major criteria air pollutants and estimate regional source-receptor relationship using air quality prediction model (TAPM ; The Air Pollution Model) in the Seoul Metropolitan area. Source-receptor relationship was estimated by contribution of each region to other regions and region itself through dividing the Seoul metropolitan area into five regions. According to administrative boundary, region Ⅰ and region Ⅱ were Seoul and Incheon in order. Gyeonggi was divided into three regions by directions like southern(region Ⅲ), northern(Ⅳ) and eastern(Ⅴ) area. Gridded emissions (1km×1km) by Clean Air Pollicy Support System (CAPSS) of National Institute of Environmental Research (NIER) was prepared for TAPM simulation. The operational weather prediction system, Regional Data Assimilation and Prediction System (RDAPS) operated by the Korean Meteorology Administration (KMA) was used for the regional weather forecasting with 30km grid resolution. Modeling period was 5 continuous days for each season with non-precipitation . The results showed that region Ⅰ was the most air-polluted area and it was 3~4 times more polluted region than other regions for NO2, SO2 and PM10. Contributions of SO2 NO2 and PM10 to region Ⅰ, Ⅱ and Ⅲ were more than 50 percent for their own sources. However region Ⅳ and Ⅴ were mostly affected by sources of region Ⅰ, Ⅱ and Ⅲ. When emissions of all regions were assumed to reduce 10 and 20 percent separately, air pollution of each region was reduced linearly and the contributions of reduction scenario were similar to those of base case. As input emissions were reduced according to different ratio - region Ⅰ 40 percent, region Ⅱ and Ⅲ 20 percent, region Ⅳ and Ⅴ 10 percent, air pollutions of region Ⅰ and Ⅲ were decreased remarkably. The contributions to regionⅠ, Ⅱ, Ⅲ were also reduced for their own sources. However, region Ⅰ, Ⅱ and Ⅲ affected more regions Ⅳ and Ⅴ. Shortly, graded reduction of emission could be more effective to control air pollution in emission imbalanced area.
The air pollutant emission is mainly caused by line sources in urban area. For example, the annually totaled air pollutant emission is known to consist of about 80% of line sources in Daegu. Hence, the appropriate assessment on the air pollutants of line sources is very important for the atmospheric environmental management in urban area. In this study, we made a comparative study to evaluate suitable dispersion model for estimating the air pollution from line sources.
Two air pollution dispersion models, ISCST3 and CALINE4 were the subject of this study. The results were as follows; In the assessment of air pollution model, ISCST3 was found to have 4 times higher concentration than CALINE4. In addition, actual data obtained by measurement and estimated values by CALINE4 were generally identical. The air pollution assessment based on ISC3 model produced significantly lower values than actual data. The air pollution levels estimated by ISCST3 were very low in comparison with the observational values.
Indoor air quality is the dominant contributor to total personal exposure because most people spend a majority of their time indoors. Especially when indoor environments have sources of contaminants, exposure to indoor air can potentially pose a greater threat than exposure to ambient air. In this study, estimations of volatile organic compounds and formaldehyde emission rate in indoor environments of new apartments were carried out using mass balance model in indoor environment, because indoor air quality can be affected by source generation, outdoor air level, ventilation, decay by reaction, temperature, humidity, mixing condition and so on. Considering the estimated emission rate of volatile organic compounds and formaldehyde, it is suggested that new apartment should be designed and constructed in the aspect of using construction materials to emit low hazardous air pollutants.
Indoor air quality has been addressed as an important atmospheric environmental issue and has caught attention of the public in recent years in Korea. Good indoor air quality in classrooms favour student's learning ability, teacher and staff's productivity according to other studies. In this study, each classroom at four different schools was chosen for comparison of indoor and outdoor air quality by means of source generation types such as new constructed classroom, using of cleaning agents and purchased furniture. Temperature, relative humidity (RH), carbon dioxide (CO2), formaldehyde (HCHO), total volatile organic compounds (TVOCs) and particulate matter with diameter less than 10 ㎛ (PM10) were monitored at indoor and outdoor locations during lesson. HCHO was found to be the worst among parameters measured in new constructed classroom, HCHO and TVOCs was worst in classroom with new purchased furniture, and TVOCs was worst in classroom cleaned by cleaning agents. Indoor CO2 concentrations often exceeded 1500 ppm indicating importance of ventilation. Active activity of students during break time made the PM10 concentration higher than a lesson. Improvements and further researches should be carried out considering indoor air quality at schools is of special concern since children and students are susceptible to poor air quality.
Air quality modeling about coastal urban region such as Pusan shoud be consider shipping source emmited from ships anchoraging and running. It has been proved at our previous studies that the ratios of air pollutants emission amount in coastal area to inland are 12.2% for NO2 and 11.7% for SO2 and the air quality of coastal urban area consierably counts on ships. Also the dispersion pattern of the air pollutants followed local circulation system in this region. Therefore this study has been developed air quality model which can describe the formation, transport, transformation and deposition processes of air pollutants considering shipping source. Currently, restriction for emission amount of ships does not exist, so our study will be useful to set the emission standard and for devising air quality policy in coastal urban region.