• Journal of Korean Society for Atmospheric Environment
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• v.18 no.5
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• pp.419-426
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• 2002

The concentrations of three different fractions of particulate matters including PM2.5, PM10, and TSP were compared between the Asian Dust (AD) and non-AD (NAD) periods during the spring season of 2001. For the purpose of this comparative analysis, the data sets were obtained from four different observatory sites located within the city boundary of Seoul that concurrently measure those three fractions of PM at hourly intervals. According to our study, several conclusions can be drawn to describe relationships between the AD event and PM distribution characteristics. First of all, it is apparent that the concentrations of PM are distinctively distinguished between AD and NAD. If the extent of contribution to the AD events are assessed on the quantitative basis, it appears that their magnitude increases on the order of PM2.5, PM10, and TSP. As a result, the increase of PM observed during AD event is dominated by the coarse rather than fine fraction of PM. Moreover, when their relationships were assessed in terms of fractional ratios, it was found that TSP/PM10 ratios were almost constant, regardless of the occurrences of AD. On the other hand, the coarse/fine or TSP/PM2.5 ratios changed dramatically between AD and NAD periods. The results of our analysis cleary distinguishes quantitative role of each PM fraction between AD and NAD period, while suggesting indirectly the possible control of source processes on such relationships.

• Journal of Korean Society for Atmospheric Environment
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• v.25 no.2
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• pp.133-140
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• 2009

In order to examine the effects of micrometeorological and climatological influences on urban scale particulate air pollutants observed in Busan, power spectrum analysis was applied to the observed particulate matter with aerodynamic diameter ${\le}10{\mu}m$ ($PM_{10}$) for the period from 1991 to 2006. Power spectrum analysis has been employed to the daily mean $PM_{10}$ concentrations obtained at 13 sites to identify different scales of periodicities of $PM_{10}$ concentrations. The results show that, aside from the typical and well-known periodicities such as diurnal and annual variations caused by anthropogenic emission influences, another two significant peaks of power spectrum density were identified: 21 day and $3{\sim}4$ year of periodicities. Cospectrum analysis indicates that the intraseasonal 21 day periodicity are found to be negatively correlated with wind speed and surface pressure but shows consistently positive with relative humidity and temperature. This result implied that 21 day periodicity is presumably relevant to the secondary aerosol formation processes through the photochemical reaction that can be subsequently resulted from hygroscopic characteristics of aerosol formation. However, the interannual $3{\sim}4$ year of periodicity is found to have positive correlation with pressure, and negative with temperature and relative humidity, which is rather consistent with both characteristics of air mass during the Asian dust event and the occurrence frequency of Asian dust whose periodicities have been recorded inter-annually over the Korean peninsula.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.5
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• pp.545-552
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• 2013

While attainment rates for $SO_2$ and CO approached 100%, those for $PM_{10}$, $NO_2$, and $O_3$ have been low during the past decade. The attainment rates for 24-h $PM_{10}$ and 8-h $O_3$ have been only 1~3% and 5~12%, respectively, since the standards were strengthened in 2007. Variations in the 99th percentiles of 24-h $PM_{10}$, 8-h $O_3$, and 24-h $NO_2$, which are used as criteria for determining exceedance of standards, were examined by region. Because the analysis was based on short-term high-concentrations, the effects of Asian dust were observed for $PM_{10}$. Accordingly, it is necessary to specify whether exceptional events such as Asian dust will be included or not in determining the exceedances of standards. While variations in $NO_2$ were not large, there was an increasing trend in $O_3$. In the Yeongnam region, the increasing rate of $O_3$ concentrations was small although the decreasing rate of $NO_2$ was the greatest. In the Gangwon region, $NO_2$ concentrations were almost unchanged, but $O_3$ concentrations experienced a significant increase. Regional management strategies targeting short-term high concentrations of criteria pollutants analogous to the Special Act for the greater Seoul area will aid in improving attainment rates.

• Journal of Environmental Science International
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• v.16 no.4
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• pp.399-407
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• 2007

The characteristics of meteorological conditions relevant to Asian dust (AD) outbreaks and their occurrence frequencies were analyzed in four source regions (R1 to R4) during spring months (March to May) of 1995-2002. Moreover, the concentration variations of AD (e.g., $PM_{10}$) observed in Korea were investigated during the study period. In the relationship between AD outbreaks and three meteorological parameters (i.e., air temperature, wind speed, and aridity), the largest AD outbreaks in April (${\sim}250$ observations) mostly occurred in R2 when air temperature ranging from 10.0 to $15^{\circ}C$ and surface wind speed from 7 to $9m\;s^{-1}$ were recorded. Moreover, the aridity ($\geq4$) in April was significantly high in R2 with the maximum frequency of AD outbreaks (i.e., 206 observations). On the other hand, the number (percentage) of days belonging to AD events observed in five Korean cities were found to be 116 (44%), 121 (46%), and 26 days (10%) in March, April, and May, respectively. The mean $PM_{10}$ concentrations were found to range from 150 to 220, 150 to 200, and 95 to $120{\mu}g\;m^{-3}$ in March, April, and May, respectively. Consequently, this implied that the AD events in Korea were found to be gradually frequent in early spring and to be affected from the large AD outbreaks observed in the source regions.

• Journal of Environmental Science International
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• v.19 no.3
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• pp.331-342
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• 2010

Aerosol physical properties have been measured at Pusan National University by using the 16-channel LPC(Laser Particle Counter), and particle characteristics have been examined for the period from Aug. 4 2007 to Dec. 30, 2008. Annual total average, seasonal average, and other averages of the meteorologically classified four categories such as Asian dust, precipitation, foggy, and clear days are respectively described here. Both annually and seasonally averaged number concentration show three peaks at the particle diameter of 0.3, 1.3, and $4{\mu}m$, respectively. However, the first peak for summer season tends to be shifted toward smaller size than other seasons, implying the strong fine particle generation. Meteorological condition shows strong contrast in aerosol concentrations. In Asian dust case, relatively lower number concentrations of fine particles (i.e., smaller than $0.5{\mu}m$) were predominant, while higher concentrations of coarse particles were found particularly for the size bigger than $0.5{\mu}m$. In precipitation day, number concentrations were decreased by approximately 30% due to the removal process of precipitation. Foggy day shows significantly higher concentrations for fine particles, implying the importance of the aerosol condensation process of micro-fine-particle growing to fine-particle. Finally the regressed particle size distribution function was fitted optimally with two log-normal distribution, and discussed the similarities and differences among four categorized cases of the Asian dust, precipitation, foggy, and clear days.

• Atmosphere
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• v.29 no.4
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• pp.501-509
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• 2019

Asian Dust is a meteorological phenomenon that sand particles are raised from the arid and semi-arid regions-Taklamakan Desert, Gobi Desert and Inner Mongolia in China-and transported by westerlies and deposited on the surface. Asian dust results in a negative effect on human health as well as environmental, social and economic aspects. For monitoring of Asian Dust, Korea Meteorological Administration operates 29 stations using a continuous ambient particulate monitor. Kim et al. (2016) developed an automatic quality check (AQC) algorithm for objective and systematic quality check of observed PM₁₀ concentration and evaluated AQC with results of a manual quality check (MQC). The results showed the AQC algorithm could detect abnormal observations efficiently but it also presented a large number of false alarms which result from valid error check. To complement the deficiency of AQC and to develop an AQC system which can be applied in real-time, AQC has been modulated. Based on the analysis of instrument status codes, valid error check process was revised and 6 status codes were further considered as normal. Also, time continuity check and spike check were modified so that posterior data was not referred at inspection time. Two-year observed PM₁₀ concentration data and corresponding MQC results were used to evaluate the modulated AQC compared to the original AQC algorithm. The results showed a false alarm ratio decreased from 0.44 to 0.09 and the accuracy and the probability of detection were conserved well in spite of the exclusion of posterior data at inspection time.

• Korean Journal of Remote Sensing
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• v.32 no.2
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• pp.97-104
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• 2016

We present linear particle depolarization ratio at 440, 675, 870, and 1020 nm retrieved from measurements with an AERONET sun/sky radiometer at Osaka, Japan. The retrieved data were compared with lidar derived linear particle depolarization ratio at 532 nm at the same site. We find good agreement between linear particle depolarization ratios derived with Sun photometer and measured by lidar except for those at 440 nm. The coefficients of determination between lidar derived data and sun/sky radiometer derived data were 0.28, 0.81, 0.88, and 0.89 at 440, 675, 870, and 1020 nm, respectively. We find that the linear particle depolarization ratio derived with sun/sky radiometer varies by the mixing between Asian dust and pollution particles. As the mixing ratio of Asian dust and pollution particles is increased, the linear particle depolarization ratio values are lower than the values of pure Asian dust. It was confirmed by the value of single-scattering albedo and particle size distribution.

• Journal of Preventive Medicine and Public Health
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• v.51 no.3
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• pp.130-139
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• 2018

Objectives: Air pollution is a growing concern in Korea because of transboundary air pollution from mainland China. A panel study was conducted to clarify the effects of air pollution on respiratory symptoms and health-related quality of life (HR-QoL) in outpatients with and without chronic obstructive pulmonary disease (COPD) in Korea. Methods: Patients filled out a questionnaire including self-reported HR-QoL in February and were followed up in May and July. The study was conducted from 2013 to 2015, with different participants each year. Air quality parameters were applied in a generalized estimating equation as independent variables to predict factors affecting HR-QoL. Results: Lower physical fitness scores were associated with Asian sand dust events. Daily activity scores were worse when there were high concentrations of particulate matter (PM) less than $10{\mu}m$ in diameter ($PM_{10}$). Lower social functioning scores were associated with high PM less than $2.5{\mu}m$ in diameter and nitrogen dioxide ($NO_2$) concentrations. High $NO_2$ concentrations also showed a significant association with mental health scores. Weather-related cough was prevalent when $PM_{10}$, $NO_2$, or ozone ($O_3$) concentrations were high, regardless of COPD severity. High $PM_{10}$ concentrations were associated with worsened wheezing, particularly in COPD patients. Conclusions: The results suggest that PM, $NO_2$, and $O_3$ cause respiratory symptoms leading to HR-QoL deterioration. While some adverse effects of air pollution appeared to occur regardless of COPD, others occurred more often and more intensely in COPD patients. The public sector, therefore, needs to consider tailoring air pollution countermeasures to people with different conditions to minimize adverse health effects.

• Journal of Korean Society for Atmospheric Environment
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• v.33 no.3
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• pp.233-240
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• 2017

To distinguish between high particulate matter (HPM) and light Asian dust (LAD) events, aerosol optical properties from GOCI were investigated in Seoul from 2014 to 2016. The poor air quality case caused by fine atmospheric particulate matter (i.e., 80<$PM_{10}$<$400{\mu}g/m^3$) is clearly separated from the case of heavy Asian dust that generally shows the $PM_{10}$ concentration more than $400{\mu}g/m^3$. In this study, we have found eight cases for the poor air quality and divided them into the two events(i.e., HPM and LAD). In case of aerosol optical depth (AOD), there was no big difference between two events. However, Angstrom exponent (AE) for HPM events was greater than 1, while that for LAD events less than 1. As a result of comparing aerosol type, non-absorbing fine mode aerosols were dominant for HPM events, but coarse and absorbing coarse mode aerosols for LAD events. Therefore, AE and aerosol type from GOCI can be used to distinguish between two events effectively.

• Atmosphere
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• v.20 no.2
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• pp.161-172
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• 2010

In an effort to investigate the characteristics of synoptic meteorological conditions in association with long-range transport of haze phenomena occurred over Korea, we statistically classified characteristics of haze events into two types of haze: stagnant case and long-range transport case, based on the synoptic meteorological parameters, and analyze comparatively the characteristics of synoptic meteorological conditions for each case. The results showed that the occurrence frequency of stagnant case accounts for 64.5%, showing superiority of stagnant haze cases over the long-range transport case which occupies only 35.5% among total 67 cases for the period from 2000 to 2007. This result indicates that haze phenomena occurred over Korea has influenced by not only the emission in Korea by itself but long range transport effects originating from China inland. The synoptic condition on 850hPa level showed that, when stagnant case occurred, Korean peninsula was located under the effects of negative vorticity with the significantly weak wind speed and stable atmospheric condition. In contrast, long-range transport case shows positive vorticity and relatively strong wind speed over 850hPa level, especially with the location of high pressure system over the area of southwestern China. This location of high pressure system implies to induce the westerlies or northwesteries consistently due to its pressure gradient by itself. Also other comparative studies haze days (vs.) Asian dust days are carried out, and we found out that the patterns of long-range transport of haze phenomena in Korea shows similar to Asian dust case but the static stability condition indicates more stabilized atmospheric condition than dust phenomena.