• Title/Summary/Keyword: atmospheric $CO_2$ concentration

Search Result 326, Processing Time 0.024 seconds

Influence of CO2 concentration on carbon concentrating mechanisms in cyanobacteria and green algae: a proteomic approach

  • Ramanan, Rishiram;Vinayagamoorthy, Nadimuthu;Sivanesan, Saravana Devi;Kannan, Krishnamurthi;Chakrabarti, Tapan
    • ALGAE
    • /
    • v.27 no.4
    • /
    • pp.295-301
    • /
    • 2012
  • Carbon concentrating mechanisms play a vital role in photosynthesis in microalgae and cyanobacteria especially in the proper functioning of Rubisco and assimilation of carbon via the Calvin cycle. This study evaluates the role of carbon dioxide on carbon concentrating mechanism (CCM) in a cynaobacteria, Spirulina platensis and a microalga, Chlorella sp. 786. The study organisms were grown in both atmospheric (control sample, 0.035%) and high (exposed sample, 10%) $CO_2$ concentrations. Second dimension (2D) electrophoresis revealed a huge difference in the protein profiles of both organisms suggesting the induction of CCM related proteins in the sample maintained at atmospheric $CO_2$ concentration and the repression of CCM related proteins in the sample maintained at 10% $CO_2$. Liquid chromatography-mass spectroscopy analysis revealed the presence of two important $C_i$ transporter proteins in the control sample of S. platensis, namely ferredoxin-$NADP^+$ reductase and ATP binding cassette (ABC) transport system protein. These proteins were only expressed in the control sample and were downregulated or not expressed at all in the exposed sample. Consequently, this study conclusively proves that CCMs are only inducted at low $CO_2$ concentrations and are not functional at high $CO_2$ concentration.

Characteristics of Seasonal Source for Formaldehyde and Acetaldehyde in Metropolitan Areas (수도권지역에서 포름알데히드와 아세트알데히드의 계절별 발생원 특성)

  • 여현구;조기철;임철수;최민규;선우영
    • Journal of Korean Society for Atmospheric Environment
    • /
    • v.18 no.1
    • /
    • pp.11-23
    • /
    • 2002
  • The concentrations of aldehydes were measured in downtown area of Buchun and Kwanghwamoon of Seoul from October 1997 to August 1998 using 2-series impingers. The data have been analysed to identify the seasonal pattern of aldehyde sources in metropolitan areas. The measured concentration (in ppbv) of aldehydes were 8.86 $\pm$ 7.28 HCHO (formaldehyde) and 7.79$\pm$7.29 $CH_3$CHO (acetaldehyde) in Buchun, while recording 10.13$\pm$8.58 (HCHO) and 7.64$\pm$6.65 ($CH_3$CHO) in Kwanghwamoon. Their diurnal variation patterns showed significant increase of HCHO and $CH_3$CHO concentration in early afternoon, indicating an increase in secondary sources. Their concentrations however decreased in the nighttime, regardless of seasons. The strength of correlations between certain pairs such as (1) HCHO and CO and (2) $CH_3$CHO and CO were generally high during the winter months (0.64< r < 0.84), suggesting the possibility of similar source processes for HCHO, $CH_3$CHO and CO. On the other hand during the summer months, their correlations are frequently lower than winter months. We suggested that the complexity of source/sink processes during the summer period may reduce the correlations between aldehyde and CO.

A Preliminary Flux Study for CO2 and Biogenic VOCs in a Forest (산림지역 이산화탄소 및 자연적휘발성유기화합물의 교환량 관측기법 기초연구)

  • Kim, So-Young;Kim, Su-Yeon;Choi, Soon-Ho;Kim, Sae-Wung
    • Journal of Korean Society for Atmospheric Environment
    • /
    • v.28 no.5
    • /
    • pp.485-494
    • /
    • 2012
  • The purpose of this study is to monitor the flux of $CO_2$ and BVOCs (biogenic volatile organic compounds) between the atmosphere and forest. The main research activities are conducted at Taehwa Research Forest (TRF), managed by the College of Agriculture and Life Sciences at Seoul National University. The TRF site is located 60 km north-east from the center of Seoul Metropolitan Area. The TRF flux tower is in the middle of a Korean Pine (Pinus Koraiensis) plantation ($400m{\times}400m$), surrounded by a mixed forest. Eddy covariance method was used for $CO_2$ flux above the forest and REA (Relaxed eddy accumulation) method applying eddy covariance was used for BVOCs flux. BVOCs flux that was measured in spring (from May 16 to 18) had distribution of 84 to $2917{\mu}g/m^2{\cdot}h$. Especially, it showed that d-limonene being strong reactivity composed the largest fraction of monoterpene. Ambient $CO_2$ concentration measured in Mt. Taehwa was 399 ppm and observed $CO_2$ fluxes between the atmosphere and forest suggested that during the day, $CO_2$ is absorbed by plants through photosynthesis and released during the night.

Decomposition of Trchloroethylene/Air Mixture by Electron Beam Irradiation in a Flow Reactor (전자빔을 이용한 흐름반응기에서의 Trichloroethylene/Air 분해)

  • ;;;Tatiana Stuchinskaya
    • Journal of Korean Society for Atmospheric Environment
    • /
    • v.17 no.1
    • /
    • pp.97-104
    • /
    • 2001
  • Decomposition of trichloroethlyene(TCE) in electron beam irradiation was examined on order to obtain information on the treatment of VOC in air. Air containing vaporized TCE has been studied in a flow reactor with different reaction environments, at various initial TCE concentration and in the presence and absence of water vapor. Maximum decomposition was observed in oxygen reaction environment and the degree of decomposition was about 99% at 20kGy for 2,000ppm initial TCE. The concentration of TCE exponentially decreased with dose in air and pure oxygen. The effect of water vapor on TCE decomposition efficiency was examined. The decomposition rate of TCE in the presence of water vapor (5,600 ppm) was approximately 10% higher than that in the absence of water vapor. Dichloroacetic acid, dichloroacethyl chloride and dichloroethyl ester acid were identified as primary products of this reaction adn were decomposed and oxidized to yield CO and $CO_2$. Perchloroethylene, hexachloroethane, chloroform and carbon tetrachloride were also observed as highly chlorinat-ed by products.

  • PDF

A Study on Air Pollution Prediction Using Adaptive Lattice Altorithm (적응격자 알고리즘을 이용한 대기오염 예측에 관한 연구)

  • 홍기용;김신도;김성환
    • Journal of Korean Society for Atmospheric Environment
    • /
    • v.2 no.3
    • /
    • pp.52-56
    • /
    • 1986
  • In this paper a adaptive LMS(least mean-square) lattice predictor, which is composed of the adaptive lattice algorithm and LMS algorithm by Widrow-Hopf, is used to predict the future air pollution of the extraordinary levels in the environmental system. This prediction algorithm is applied to the one-step forward prediction of atmospheric CO concentration by using real observed data. Computer simulation proves that the power in the forward error sequences decreases as the number of stages in the lattice is increased.

  • PDF

Preliminary Report of Observed Urban - Rural Gradient of Carbon Dioxide Concentration across Seoul, Suwon, and Icheon in South Korea (도시 - 전원간 이산화탄소(CO2) 농도구배 예비관측 결과)

  • Chung, U-Ran;Lee, Kyu-Jong;Lee, Byun-Woo
    • Korean Journal of Agricultural and Forest Meteorology
    • /
    • v.9 no.4
    • /
    • pp.268-276
    • /
    • 2007
  • Urban atmosphere may play as a harbinger for the future climate change with respect to temperature and $CO_2$ concentration. The Seoul metropolitan area is unique in rapid urbanization and industrialization during the last several decades, providing a natural $CO_2$ dome with increased temperature. This study was carried out to evaluate the feasibility of using the urban-rural environmental gradient in replacement of the IPCC mid-term scenario (after 30-50 years). For this, we measured atmospheric $CO_2$ concentration and air temperature at three sites with different degree of urbanization (Seoul, Suwon, and Icheon). Results from 11-month measurement can be summarized as follows: (1) The annual mean $CO_2$ concentration across 3 sites was in the order of Seoul (439 ppm) > Suwon (419 ppm) > Icheon (416 ppm), showing a substantial urban-rural environmental gradient. (2) The diurnal fluctuation in $CO_2$ concentration was greater in summer than in winter, showing the effect of photosynthesis on local $CO_2$ concentration. (3) The daily maximum $CO_2$ concentration was observed at 0500 LST in spring and summer, 0800 LST in autumn, and 0900 LST in winter, showing the sunrise-time dependence. (4) The observed hourly maximum $CO_2$ concentration averaged for the whole period was 446 ppm in Seoul at 0700 LST, while the minimum was 407 ppm in Suwon at 1500 LST. (5) Compared with the background atmospheric concentration of $CO_2$ in Anmyeon-do (377.4 ppm annual mean), $CO_2$ concentration of the study sites was higher by 14% in Seoul, by 10% in Suwon, and by 9% in Icheon. The observed $CO_2$ concentration in Seoul reached already 98% of the 2030-2040 projection (450 ppm) and 80% of the 2040-2050 projection (550 ppm) under the IPCC BAU scenario, showing a feasibility of using the $CO_2$ dome of Seoul as a natural experimental setting for the mid-term climate change impact assessment.

Air Quality in the Subway Cabins of the Seoul Metropolitan Area and Analysis of Its Influencing Factors Using Multivariate Statistics (수도권 전동차에서의 공기질 현황 및 다변량 통계분석을 이용한 공기질 영향인자 분석)

  • Park, Eun-Young;Park, Duck-Shin;Cho, Young-Min;Kwon, Soon-Bark;Choi, Kyung-Hee;Kwon, Myung-Hee
    • Journal of Korean Society for Atmospheric Environment
    • /
    • v.27 no.2
    • /
    • pp.142-151
    • /
    • 2011
  • In this study, we have observed PM-10 and $CO_2$ concentration in the subway cabins and analyzed the factors affecting air quality using a multivariate statistical analysis. The measurements have been conducted at Seoul metropolitan subway lines. The results show that the mean concentration of the PM-10 and $CO_2$ inside subway cabins is in the range of 62.6 to 108.0 ${\mu}g/m^3$ and 907 to 2,008 ppm, respectively. $CO_2$ level in specific sections during the rush hours has exceeded air quality guidelines for public transportation, which requires designated train ventilation controls. Correlation and regression analyses of influencing factors imply that $CO_2$ level is severely influenced by the number of passengers and PM-10 level is also correlated with the number of passengers. In particular, PM-10 level in the cabins indicates a positive correlation with outdoor PM-10 level. In addition, the PM concentration has been highly affected by the number of passengers and distance between stations.

Concentration Variation of Atmospheric Radon and Gaseous Pollutants Related to the Airflow Transport Pathways during 2010~2015 (대기 라돈 및 기체상 오염물질의 기류 이동경로별 농도변화: 2010~2015년 측정)

  • Song, Jung-Min;Kim, Ki-Ju;Bu, Jun-Oh;Kim, Won-Hyung;Kang, Chang-Hee;Chambers, S.
    • Journal of Korean Society for Atmospheric Environment
    • /
    • v.34 no.2
    • /
    • pp.321-330
    • /
    • 2018
  • Concentrations of the atmospheric radon and gaseous pollutants were measured at the Gosan site on Jeju Island from 2010 to 2015, in order to observe their time-series variation characteristics and examine the concentration change related to the airflow transport pathways. Based on the realtime monitoring of the atmospheric radon and gaseous pollutants, the daily mean concentrations of radon ($^{222}Rn$) and gaseous pollutants($SO_2$, CO, $O_3$, $NO_x$) were $2,400mBq\;m^{-3}$ and 1.3, 377.6, 41.1, 3.9 ppb, respectively. On monthly variations of radon, the mean concentration in October was the highest as $3,033mBq\;m^{-3}$, almost twice as that in July ($1,452mBq\;m^{-3}$). The diurnal variation of radon concentration shows bimodal curves at early morning (around 7 a.m.) and near midnight, whereas its lowest concentration was recorded at around 3 p.m. Several gaseous pollutants($SO_2$, CO, $NO_x$) showed a similar seasonal variation with radon concentration as high in winter and low in summer, whereas the $O_3$ concentrations had a bit different seasonal trend. According to the cluster back trajectory analysis, the frequencies of airflow pathways moving from continental North China, East China, Japan and the East Sea, the Korean Peninsula, and North Pacific Ocean routes were 36, 37, 10, 13, and 4%, respectively. When the airflow were moved to Jeju Island from continental China, the concentrations of radon and gaseous pollutants were relatively high. On the other hand, when the airflows were moved from North Pacific Ocean and East Sea, their concentrations were much lower than those from continental China.

Influence of Diverse Atmospheric Conditions on Optical Properties of a Pulse Laser in a Time-of-Flight Laser Range Finder

  • Shim, Young Bo;Kwon, Oh-Jang;Choi, Hyun-Yong;Han, Young-Geun
    • Journal of the Optical Society of Korea
    • /
    • v.19 no.1
    • /
    • pp.1-6
    • /
    • 2015
  • We investigate the propagation characteristics of a pulse laser in a time-of-flight laser range finder (TOF-LRF) system with variations in atmospheric conditions, such as temperature, pressure, relative humidity, and the concentration of $CO_2$. The measurement error of distance related with the group velocity change in the TOF-LRF system is analyzed by considering the refractive index of the standard atmosphere with variations in atmospheric conditions. The dependence of the pulse width broadening induced by chromatic dispersion of the standard atmosphere on the operating wavelength and the initial pulse width of the light sources is discussed. The transmission of air with variations in the relative humidity or the concentration of $CO_2$ is analyzed by using different values of absorption coefficients depending on the operation wavelength of the light source in the TOF-LRF system.

A Study on the Relationship of Air Pollution and Meteorological Factors : Focusing at Kwanghwamun in Seoul (대기오염농도와 기상인자의 관련성 연구: 서울 광화문지점을 중심으로)

  • 신찬기;한진석;김윤신
    • Journal of Korean Society for Atmospheric Environment
    • /
    • v.8 no.4
    • /
    • pp.213-220
    • /
    • 1992
  • Simple correlation analysis, factor analysis, and multi-variate analysis have been performed to analyze the relationship between air pollution and meteorological factors for air pollution and meteorological data measured at Kwanghwamun in Seoul during the period of one year(January 1990 $\sim$ December 1990). As a result of simple correlation and factor analysis, $SO_2$, TSP and CO concentrations have shown high negative correlation with temperature and among these indicating that these are related with pollutant emission trend based upon heating fuel usage. Ozone has a good corrleation with solar radiation and relative humidity to have a closed relation with $O_3$ generation reaction mechanism. The result of multi-variate correlation analysis shows that the concentration of $SO_2$ and CO are adequate for correlation model with ambient temperature and wind speed and $O_3$ concentrations are adequate for that with solar radiation and wind speed. $SO_2$ and CO levels are considered to be affected first of all by heating fuel usage as a emssion source and wind speed as a dispersion effect. The $SO_2$ concentration in the condition that the temperature fall below zero is explained by multilicative model with wind speed, only one variable.

  • PDF