• 제목/요약/키워드: Dioxide nitrogen

검색결과 554건 처리시간 0.03초

수동식 시료채취기를 이응한 사무실 직장인의 산화질소 노출평가 및 예측 -한국의 서울과 호주의 브리스베인 비교 연구- (Exposure Assessment and Estimation of Nitrogen Dioxide on Office Worker Using Passive Monitor -Comparative Study of Seoul in Korea and Brisbane in Australia-)

  • 양원호;손부순;김종오
    • 한국환경과학회지
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    • 제11권3호
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    • pp.247-255
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    • 2002
  • Indoor and outdoor nitrogen dioxide (NO$_2$) concentrations were measured and compared with measurements of personal exposures of 95 persons in Seoul, Korea and 57 persons in Brisbane, Australia, respectively. Time activity diary was used to determine the impact on NO$_2$ exposure assessment and microenvironmental model to estimate the personal NO$_2$ exposure. Most people both Seoul and Brisbane spent their times more than 90% of indoor and more than 50% in home, respectively. Personal NO$_2$ exposures were significantly associated with indoor NO$_2$ levels with Pearson coefficient of 0.70 (p<0.01) and outdoor NO$_2$ levels with Pearson coefficient of 0.66 (p<0.01) in Seoul and of 0.51 (p<0.01) and of 0.33 (p<0.05) in Brisbane, respectively. Using microenvironmental model by time weighted average model, personal NO$_2$ exposures were estimated with NO$_2$ measurements in indoor home, indoor office and outdoor home. Estimated NO$_2$ measurements were significantly correlated with measured personal exposures (r = 0.69, p<0.001) in Seoul and in Brisbane (r = 0.66, p<0.001), respectively. Difference between measured and estimated NO$_2$ exposures by multiple regression analysis was explained that NO$_2$ levels in near workplace and other outdoors in Seoul (p = 0.023), and in transportation in Brisbane (p = 0.019) affected the personal NO$_2$ exposures.

나노펄스 코로나 방전의 온도 변화에 따른 이산화황 및 일산화질소 제거에 관한 실험적 연구 (The Experimental Study on Removal of Sulfur Dioxide and Nitrogen Oxide Using a Nano-Pulse Corona Discharger at Different Temperatures)

  • 한방우;김학준;김용진
    • 한국대기환경학회지
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    • 제27권4호
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    • pp.387-394
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    • 2011
  • A study on the removal of sulfur dioxide and nitrogen oxide was carried out using a non-thermal nano-pulse corona discharger at different gas temperatures. Pulse voltage with a high voltage of 50 kV, a pulse rising time of about 100 ns, a full width at half maximum of about 500 ns and a frequency of 1 kHz was applied to a wire-cylinder corona reactor. Ammonia and propylene gases were added into the corona reactor as additives with a static mixer. Ammonia addition had less effect on $SO_2$ reduction at the higher temperature because of the retardation of ammonium sulfate formation. However, propylene addition enhanced NO reduction at higher temperature due to increased gas mixture. $SO_2$ was further removed at the mixed $SO_2$ and NO gas due to increased $NO_2$ by the conversion of NO. The addition of ammonia and propylene gases was more highly dominant for the removal of sulfur dioxide compared to the sole pulse corona without the additives. However, the specific energy density per unit concentration of pulse corona as well as propylene additive was an important factor to remove NO gas. Therefore, the specific energy density per unit concentration of 0.04 Wh/($m^3{\cdot}ppm$) was necessary for the NO removal of more than 80% with the concentration ratio of 2.0 for propylene and NO. Hydrogen peroxide was another alternative additive to remove both $SO_2$ and NO in the nano-pulse corona discharger.

Short-term Effect of Ambient Air Pollution on Emergency Department Visits for Diabetic Coma in Seoul, Korea

  • Kim, Hyunmee;Kim, Woojin;Choi, Jee Eun;Kim, Changsoo;Sohn, Jungwoo
    • Journal of Preventive Medicine and Public Health
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    • 제51권6호
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    • pp.265-274
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    • 2018
  • Objectives: A positive association between air pollution and both the incidence and prevalence of diabetes mellitus (DM) has been reported in some epidemiologic and animal studies, but little research has evaluated the relationship between air pollution and diabetic coma. Diabetic coma is an acute complication of DM caused by diabetic ketoacidosis or hyperosmolar hyperglycemic state, which is characterized by extreme hyperglycemia accompanied by coma. We conducted a time-series study with a generalized additive model using a distributed-lag non-linear model to assess the association between ambient air pollution (particulate matter less than $10{\mu}m$ in aerodynamic diameter, nitrogen dioxide [$NO_2$], sulfur dioxide, carbon monoxide, and ozone) and emergency department (ED) visits for DM with coma in Seoul, Korea from 2005 to 2009. Methods: The ED data and medical records from the 3 years previous to each diabetic coma event were obtained from the Health Insurance Review and Assessment Service to examine the relationship with air pollutants. Results: Overall, the adjusted relative risks (RRs) for an interquartile range (IQR) increment of $NO_2$ was statistically significant at lag 1 (RR, 1.125; 95% confidence interval [CI], 1.039 to 1.219) in a single-lag model and both lag 0-1 (RR, 1.120; 95% CI, 1.028 to 1.219) and lag 0-3 (RR, 1.092; 95% CI, 1.005 to 1.186) in a cumulative-lag model. In a subgroup analysis, significant positive RRs were found for females for per-IQR increments of $NO_2$ at cumulative lag 0-3 (RR, 1.149; 95% CI, 1.022 to 1.291). Conclusions: The results of our study suggest that ambient air pollution, specifically $NO_2$, is associated with ED visits for diabetic coma.

A study on measurement of particulate matter, nitrogen oxide and carbon oxide from main engine in training ship

  • Choi, Jung-Sik;Choi, Jae-Hyuk
    • Journal of Advanced Marine Engineering and Technology
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    • 제37권7호
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    • pp.792-798
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    • 2013
  • In this study, we have carried out measurement for exhaust emissions such as particulate matter (PM), nitrogen oxide and carbon oxide from main engines installed on the training ships, HANBADA and HANNARA, of Korea Maritime University. In particular, we considered the two conditions; at arrivals/departures and at constant speed of about 160 rpm. The result showed that the concentration of PM at the ship arrival was 2.41mg/m3. On the other hand, when the ship is on the navigation condition, the concentration of PM was 1.34 mg/m3. The concentrations of nitrogen oxide and carbon oxide were measured in the range of 1,120~1,600 ppm and 320~1,450 ppm at the arrival and departure at the port. Under constant speed condition, the concentrations of nitrogen oxide and carbon oxide were 913~1,470 ppm and 73~460 ppm, respectively. Generally, the concentrations of exhaust emissions under the arrivals and departures were higher than that of constant speed condition. These results imply that the ship operation skill to prevent a sudden load change of main engine is needed during the arrival or departure. In addition, it means that the difference of exhaust emissions according to navigation conditions has to be considered when the reduction technologies of air pollutants from ships are developed.

자동차 선적작업장의 공기오염 실태조사 (Investigation into Air Pollution in Car Shipping Workshop in Pyeongtaek Port)

  • 김지호;원종욱;김치년;노재훈
    • 한국산업보건학회지
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    • 제16권1호
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    • pp.44-53
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    • 2006
  • This study purposed to investigate air pollution in car shipping yards and, for this purpose, we selected an outdoor open-air yard and an indoor ramp into the ship and measured the concentrations of sulfur dioxide, nitrogen dioxide, carbon monoxide, PM10, PM2.5 and heavy metals in the air. The results of this study are as follows. No significant difference was observed in temperature and humidity between the outdoor and indoor workshop, and the average air flow was 0.52 m/s in the indoor workshop, which is higher than 0.19 m/s in the outdoor workshop(p<0.01). The average concentrations of sulfur dioxide, nitrogen dioxide, carbon monoxide, PM10 and PM2.5 according to workplace were 0.03 ppm(${\pm}0.01$), 0.03 ppm(${\pm}0.01$), 0.46 ppm(${\pm}0.22$), $39.44{\mu}g/m^3$(${\pm}2.45$) and $5.45{\mu}g/m^3$(${\pm}1.15$) respectively in the outdoor workshop, and 0.15 ppm(${\pm}0.05$), 0.22 ppm(${\pm}0.06$), 8.85 ppm(${\pm}3.35$), $236.39{\mu}g/m^3$(${\pm}58.21$) and $152.43{\mu}g/m^3$(${\pm}35.42$) respectively in the indoor workshop. Thus, the concentrations of gaseous substances in the indoor workshop were 4.9-19.2 times higher than those in the outdoor workshop, and the concentrations of fine dusts were 5.9-27.9 times higher(p<0.01). In addition, according to the result of investigating pollutant concentrations according to displacement and the number of car loaded when shipping gasoline cars into the ship, no significant relation between the number of cars loaded and pollutants was observed in shipping passenger cars, but the concentrations of nitrogen dioxide and carbon monoxide got somewhat higher with the increase of the number of cars loaded(p<0.05). In addition, the concentrations of nitrogen dioxide, carbon monoxide, PM10 and PM2.5 in the air were significantly higher when shipping recreational vehicles, the displacement of which is larger than passenger cars, than when shipping passenger cars(p<0.01). On the other hand, the average heavy metal concentrations of the air in indoor workshop were: lead $-0.05{\mu}g/m^3$(${\pm}0.10$); chromium $-0.90{\mu}g/m^3$(${\pm}0.18$); zinc $-0.38{\mu}g/m^3$(${\pm}0.24$); copper $-0.18{\mu}g/m^3$(${\pm}0.22$); and manganese and cadmium not detected. In addition, the complaining rates of 'asthma,' a major symptom of chronic respiratory diseases, were 18.5% and 22.5% respectively in indoor workers and outdoor workers. Thus the rate was somewhat higher in indoor workers but the difference was not statistically significant. The complaining rates of 'chronic cough' and 'chronic phlegm' were very low and little different between indoor and outdoor workers. The results of this study show that the reason for the higher air pollution in indoor than in outdoor workshop is incomplete combustion of fuel due to sudden start and over-speed when cars are driven inside the ship. In order to prevent high air pollution, efficient management measures should be taken including the observance of the optimal speed, the improvement of old ships and the installation of efficient ventilation system.

고압 밀도계의 보정에 대한 연구 (Calibration of High Pressure Vibrating Tube Densimeter)

  • 김화용;오경실;배원
    • 한국가스학회지
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    • 제9권3호
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    • pp.49-54
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    • 2005
  • 본 연구에서는 넓은 범위의 온도(420 K), 압력(70 MPa)에서 밀도를 측정할 수 있는 Anton Paar DMA 512P vibrating tube densimeter를 보정하고, 장치의 건전성을 확인하였다. 보정을 위해서 기준물질로 물과 질소 그리고 물과 진공의 period를 측정하여 각각을 비교해보았다. 온도는 313.15부터 353.15 K까지 10 K 간격으로 5 isotherms를 측정하였고, 압력은 5부터 30 MPa까지 대략 5 MPa 간격으로 측정하였다. 또한 이산화탄소의 밀도를 측정하여 NIST에 보고된 밀도값과 비교해 보았다. 기준물질로 물과 진공보다 물과 질소를 사용하였을 때 더 좋은 결과를 보였고, 이산화탄소의 경우 측정범위 내에서는 오차가 대략 $0.3\%$로 비교적 낮은 결과를 보였으며 이로써 장치의 건전성을 확인하였다.

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고성능 메탄올 산화 반응을 위한 이산화 티타늄 복합화된 질소 도핑 탄소 지지체의 합성 (Synthesis of TiO2 Composited Nitrogen-doped Carbon Supports for High-Performance Methanol Oxidation Activity)

  • 조현기;안효진
    • 한국재료학회지
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    • 제30권1호
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    • pp.14-21
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    • 2020
  • Carbon supports for dispersed platinum (Pt) electrocatalysts in direct methanol fuel cells (DMFCs) are being continuously developed to improve electrochemical performance and catalyst stability. However, carbon supports still require solutions to reduce costs and improve catalyst efficiency. In this study, we prepare well-dispersed Pt electrocatalysts by introducing titanium dioxide (TiO2) into biomass based nitrogen-doped carbon supports. In order to obtain optimized electrochemical performance, different amounts of TiO2 component are controlled by three types (Pt/TNC-2 wt%, Pt/TNC-4 wt%, and Pt/TNC-6 wt%). Especially, the anodic current density of Pt/TNC-4 wt% is 707.0 mA g-1pt, which is about 1.65 times higher than that of commercial Pt/C (429.1 mA g-1pt); Pt/TNC-4wt% also exhibits excellent catalytic stability, with a retention rate of 91 %. This novel support provides electrochemical performance improvement including several advantages of improved anodic current density and catalyst stability due to the well-dispersed Pt nanoparticles on the support by the introduction of TiO2 component and nitrogen doping in carbon. Therefore, Pt/TNC-4 wt% may be electrocatalyst a promising catalyst as an anode for high-performance DMFCs.

RF-PECVD법에 의해 증착된 DLC 박막의 결합구조와 기계적 특성에 관한 보조가스의 영향 (Effect of the additive gas on the bonding structure and mechanical properties of the DLC films deposited by RF-PECVD)

  • 최봉근
    • 한국결정성장학회지
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    • 제25권4호
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    • pp.145-152
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    • 2015
  • rf-PECVD 방법에 의해서 $CH_4+H_2$ 혼합가스를 이용Si-웨이퍼 위에 DLC 박막을 증착할 때, 이산화탄소나 질소 등 보조가스가 증착된 박막의 결합구조와 기계적 특성에 미치는 영향을 고찰하였다. DLC 박막의 증착속도는 rf-power가 증가함에 따라서 증가하지만, 보조가스의 양이 증가함에 따라서는 감소하였다. 또한, 이산화탄소($CO_2$) 가스가 증가함에 따라 박막내 수소 함량은 감소하였으나, $sp^3/sp^2$ 결합 비는 증가하였다. 질소($N_2$) 가스가 증가하는 경우는 수소 함량은 감소하였으나, $sp^3/sp^2$ 결합비 변화에 있어 경향성은 보이지 않는 것으로 확인되었다.

Ethylcellulose와 금속염을 이용한 고분자-금속 착체막의 제조 및 기체투과특성 (Preparation of Polymer-Metal Complexed Membranes using Ethylcellulose and Metal salts, and Their Characteristics of Gas Separation.)

  • 변홍식;서성호;박병규;홍병표;백승욱;박영규
    • 멤브레인
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    • 제13권3호
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    • pp.200-209
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    • 2003
  • Ethyl cellulose(EC)와 platinum(II) acetylacetonate(Pt), rhodium(III)acetylacetonate(Rh)를 이용하여 용매증발법으로 고분자-금속 착체막을 제조하였다. 이때 최종 분리막의 제막조건을 최적화하기 위하여 금속염의 조성을 변화시켰다. (0.3-4.0 wt%). FTIR을 이용하여 EC-금속착체막을 분석하였으며 SEM을 이용하여 막의 구조를 관찰하였다. 그리고 산소, 질소, 이산화탄소, 메탄 가스들의 투과성능을 조사하였다. 금속염들은 모든 가스들의 선택도의 감소없이 투과도를 향상시킨다는 것을 알 수 있었다 그러나 Pt의 경우 산소와 질소가스의 투과성능에 더 영향이 있었으며, Rh은 이산화탄소와 메탄가스의 투과도에 더 영향이 있음을 알 수 있었다. EC-Pt 착체막의 경우에는, Pt의 산소와의 친화력특성에 기인하여 산소/질소의 선택도가 증가(37%)하는 것을 보여주었다.

Chemical Doping of $TiO_2$ with Nitrogen and Fluorine and Its Support Effect on Catalytic Activity of CO Oxidation

  • Chakravarthy, G. Kalyan;Kim, Sunmi;Kim, Sang Hoon;Park, Jeong Young
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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    • pp.142.2-142.2
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    • 2013
  • The effect of substrate on catalytic activity of CO oxidation with transition metal Platinum nanoparticles on doped and undoped TiO2 was investigated. Titanium dioxide was doped chemically with non-metal anions including nitrogen and fluorine. Undoped TiO2 was synthesized via simple conventional sol-gel route. Thin films of titania were developed by spin coating technique and the characterization techniques SEM, XRD, UV-Vis Absorption Spectroscopy and XPS were carried out to examine the morphology of films, crystal phase, crystallites, optical properties and elemental composition respectively. XPS analysis from doped TiO2 confirmed that the nitrogen site were interstitial whereas fluorine was doped into TiO2 lattice substitutionally. Catalytic activity systems of Pt/doped-TiO2 and Pt/undoped-TiO2 were fabricated to reveal the strong metal-support interaction effect during catalytic activity of CO oxidation reactions. By arc plasma deposition technique, platinum nanoparticles with mean size of 2.7 nm were deposited on the thin films of doped and undoped titanium dioxide. The CO oxidation was performed with 40 Torr CO and 100 Torr O2 with 620 Torr He carrier gas. Turn over frequency was observed two to three folds enhancement in case of Pt/doped TiO2 as compared to Pt/TiO2. The electronic excitation and the oxygen vacancies that were formed with the doping process were the plausible reasons for the enhancement of catalytic activity.

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