• Publications of The Korean Astronomical Society
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• v.32 no.1
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• pp.151-153
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• 2017

Early-type galaxies (ETGs) are generally dominated by old low-mass stars, which are not very productive of dust, and hot interstellar plasmas, which are very destructive of dust. Thus ETGs provide harsh environments for survival of dust. It has been found that some ETGs contain a large amount of dust, and yet its supply mechanism is not understood well. We present the result of a systematic study of dust in ETGs with the AKARI mid- and far-infrared all-sky surveys. From the AKARI result and the Ks band data obtained by ground-based telescopes, we find that there is a global correlation between the dust mass and stellar luminosity. We also compare the AKARI all-sky survey result with the CO data to discuss origins of dust in ETGs.

• Publications of The Korean Astronomical Society
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• v.27 no.4
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• pp.263-264
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• 2012

We present the properties of dust and the near-infrared spectral features in nearby early-type galaxies. The properties of dust are obtained from the AKARI far-infrared all-sky survey diffuse map. The AKARI/IRC is used for the near-infrared spectra. We improve spectral data with the new dark subtraction method on the basis of the knowledge acquired in our laboratory experiments of the engineering-model detector for the IRC. We have succeeded in fitting the continuum by a power-law function and detecting CO and SiO absorption features in early-type galaxy spectra. Comparing the properties of dust and near-infrared spectral features, we find that the power-law slope depends on dust temperature, but not on the dust mass, which suggests that low-luminosity AGNs may contribute to the changes in the power-law slope and dust temperature.

• Proceedings of the KSRS Conference
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• 1999.11a
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• pp.89-94
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• 1999

The paper first proposes an empirical algorithm for detecting dust-loaded airmass observed by Sea Wide Field-of-view Scanner (SeaWiFS). The proposed dust index formula is based on the curvature of the spectral reflectance estimated from the SeaWiFS band 4 (510 nm band) through band 8 (865 nm band) data, assuming "clear ocean water" reflectance. Evaluation of the algorithm is made over several typical Asian dust images including the ones over the Pacific in April, 1998, when a major dust event was reported. The study analyzes the performance and the characteristics of the algorithm by comparing the satellite-derived dust index images with contemporaneous columnar concentration of dust particles predicted by a numerical dust transport model. The comparison reveals several small-scale differences although their dust distribution patterns show good agreement generally.

• Journal of Korean Public Health Nursing
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• v.16 no.1
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• pp.30-44
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• 2002

The purpose of this study were to identify seasons variation of house dust mites allergen and perceived allergic symptom. The subjects were consisted of 29 family with allergy patients and 34 family without allergy patients. Perceived allergic symptoms were accessed and house dust was sampled from beds, floor of bedroom, kitchen and livingroom in spring(August), summer (July), fall(October) and winter(January) and tested using two-site ELISA. The results were as follows; 1) In all family, amount of house dust mites allergen(Der fI) of livingroom floor was the highest in summer$(4.73{\mu}g/1g\;of\;dust)$, and then fall$4.67{\mu}g/1g\;of\;dust)$, winter$(3.94{\mu}g/1g\;of\;dust)$, spring$(1.73{\mu}g/1g\;of\;dust)$. 2) In family with allergy patients, amount of house dust mites allergen(Der fI) of bedroom floor was highest in fall $(9.75{\mu}g/1g\;of\;dust)$. 3) In family with allergy patients, amount of house dust mites allergen(Der fI) of mattress was highest in fall$(8.23{\mu}g/1g\;of\;dust)$. 4) Perceived allergic symptom scores of family with allergy patients were higher than family without allergy patients in all seasons. In family without allergy patients, perceived allergic symptom scores was the highest in spring(4.29) and perceived allergic symptom scores of family with patients was the highest in winter(2.49). 5) The relationship of house dust mites allergen and perceived allergic symptom scores were positively related (r=.941, p=.000). Perceived allergic symptoms were correlated with amount of house dust mites allergen, That is, perceived allergic symptoms were became worse by house dust mites allergen. So House dust mites allergen reducing strategies and intervention should be recommended in further study.

• Hwankyungkyoyuk
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• v.21 no.2
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• pp.51-67
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• 2008

The purpose of this study is to develop and applicate the elementary environmental textbook in order to solve its problem and to improve attitude related to the Asian dust. The results in this research are as follows. First, it was showed that three groups who composed of teachers, parents and students in the elementary school had recognized the serosities and problems caused by the Asian dust form TV, and that such problems was associated with increase of the desertification and the global warming. Especially the student group insist that the cause in Asian dust is due to the natural phenomena or industrialization. Second, as a result in analysis on the Asian dust through both textbooks on the 7th elementary curriculum and subsidiary textbooks, contents concerning Asian dusts was little or noting. In addition, in the subjects of Science, Society and Health for the 5th and 6th grade students in the elementary school, they were explained partially as one of the air pollutants. Third, the elementary environmental textbook on the Asian dust was developed for the 5th and 6th grade students. The textbook is composed of four contents on the material which is harmful of the human health and life in Asian dust, the special news of Asian dust, and the best answer to solve Asian dust as well as the cause and the source of Asian dust. Forth, as a result in classes using the environmental textbook developed by four themes about the Asian dust, its application is meaningful in the level of p value in the view of knowledge, awareness and attitude of the experiment group. They was more improved in 37%, 14%, and 15%, respectively, than the comparative group. In conclusion, the environmental textbook related to Asian dust will play an important role in useful tool to understand the right knowledge, awareness, and attitude which makes an effort on its effective management in the elementary school.

• Publications of The Korean Astronomical Society
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• v.32 no.1
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• pp.77-81
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• 2017

A wide spectral coverage from near-infrared (NIR) to far-infrared (FIR) of AKARI both for imaging and spectroscopy enables us to efficiently study the emission from gas and dust in the interstellar medium (ISM). In particular, the Infrared Camera (IRC) onboard AKARI offers a unique opportunity to carry out sensitive spectroscopy in the NIR ($2-5{\mu}m$) for the first time from a spaceborn telescope. This spectral range contains a number of important dust bands and gas lines, such as the aromatic and aliphatic emission bands at 3.3 and $3.4-3.5{\mu}m$, $H_2O$ and $CO_2$ ices at 3.0 and $4.3{\mu}m$, CO, $H_2$, and H I gas emission lines. In this paper we concentrate on the aromatic and aliphatic emission and ice absorption features. The balance between dust supply and destruction suggests significant dust processing taking place as well as dust formation in the ISM. Detailed analysis of the aromatic and aliphatic bands of AKARI observations for a number of H ii regions and H ii region-like objects suggests processing of carbonaceous dust in the ISM. The ice formation process can also be studied with IRC NIR spectroscopy efficiently. In this review, dust processing in the ISM divulged by recent analysis of AKARI data is discussed.

• Journal of Korean Society for Atmospheric Environment
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• v.28 no.1
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• pp.1-11
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• 2012

A case study was conducted for a severe wintertime dust event that occurred on December 29, 2007 in Korea. Three different dust emission schemes, namely, those of Marticorena and Bergametti (1995), Lu and Shao (1999), and Shao (2004) (hereinafter, referred to MB, LS, and S04 schemes, respectively) were implemented in Weather Research Forecast with Chemistry (WRF/Chem) to assess their performance in simulating wintertime Asian dust events. WRF/Chem simulation reproduces dust emission over Mongolia on December 27 and 28, 2007 and the onset timing of the dust event in Korea well. There is, however, a huge difference among the estimated dust emission amounts for the three schemes; the dust concentration derived by MB scheme is 6 times larger than that from LS scheme. The three schemes overestimate dust concentrations when comparing to observed surface-level $PM_{10}$ mass concentrations in Ganghwa, Seoul, and Yeongwol. This discrepancy is thought to be mainly due to the overestimated model winds and the surface condition such as snow cover fraction, which did not adequately represent the real conditions. Considering frozen soil effect on dust emission, the model results are comparable with observation data: it is important to consider frozen soil in simulating wintertime dust events.

• Publications of The Korean Astronomical Society
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• v.32 no.1
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• pp.97-99
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• 2017

Our understanding of dust emission, interaction, and evolution, is evolving. In recent years, electric dipole emission by spinning dust has been suggested to explain the anomalous microwave excess (AME), appearing between 10 and 90 Ghz. The observed frequencies suggest that spinning grains should be on the order of 10nm in size, hinting at polycyclic aromatic hydrocarbon molecules (PAHs). We present data from the AKARI/Infrared Camera (IRC) due to its high sensitivity to the PAH bands. By inspecting the IRC data for a few AME regions, we find a preliminary indication that regions well-fitted by a spinning-dust model have a higher $9{\mu}m$ than $18{\mu}m$ intensity vs. non-spinning-dust regions. Ongoing efforts to improve the analysis by using DustEM and including data from the AKARI Far Infrared Surveyor (FIS), IRAS, and Planck High Frequency Instrument (HFI) are described.

• Journal of Environmental Science International
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• v.20 no.4
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• pp.493-500
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• 2011

This study investigates the relationship between Asian dust and asthma disease in Seoul, using data of Asian dust occurrences and the number of treatments for asthma between 2005 and 2008. The data include the number of treatments for asthma on the basic day paired with the average number of treatments for asthma on the compared days. The compared day is defined by the day of no Asian dust in same month and day of the week as the basic day, when Asian dust occurs. Also, the basic day is expanded to the day after three days from the day of Asian dust. The paired two sample t-test for the number of treatments for asthma on the basic day and the compared days revealed that the Asian dust occurrences are correlated with the asthma disease. The number of treatments for asthma is significantly increased on the one and two days after Asian dust occurs. On the other hand, there's no significant difference in the number of treatments for asthma between the days of Asian dust occurrence and the days of no Asian dust, which implies that people usually try not to go out when Asian dust occurs.

• Journal of Korean Society for Atmospheric Environment
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• v.28 no.1
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• pp.86-93
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• 2012

We present a retrieval method to obtain dust backscatter coefficient from the mixed Asian dust and pollutant layer. In the present study, vertically resolved quartz (silicon dioxide, silica) concentration was calculated using Raman scattering signals from quartz at 546 nm. Dust concentration was obtained based on typical mass percentage of quartz in Asian dust. The highest value of dust concentration at 3.7 km in March 21, 2010 was 22.3 and 10.9 ${\mu}gm^{-3}$ according to the quartz percentage in Asian dust as 65 and 30% based on literature survey, respectively. OPAC (Optical Properties of Aerosol and Clouds) simulations were conducted to calculate dust backscatter coefficient. The retrieved dust concentration was used as an input parameter for the OPAC calculations. Utilization of quartz Raman channel in Lidar measurements is considered useful for distinguishing optical properties of dust and nondust aerosol in the mixing state of Asian dust.