• Journal of Korean Society for Atmospheric Environment
• /
• v.34 no.5
• /
• pp.668-676
• /
• 2018

This study has developed a technique to divide the aerosol optical depth of the entire aerosol (${\tau}_{total}$) into the dust optical depth (${\tau}_D$) and the pollution particle optical depth (${\tau}_P$) using the AERONET sun/sky radiometer data provided in Version 3. This method was applied to the analysis of AERONET data observed from 2006 to 2016 in Beijing, China, Seoul and Gosan, Korea and Osaka, Japan and the aerosol optical depth trends of different types of atmospheric aerosols in Northeast Asia were analyzed. The annual variation of ${\tau}_{total}$ showed a tendency to decrease except for Seoul where observation data were limited. However, ${\tau}_D$ tended to decrease when ${\tau}_{total}$ were separated as ${\tau}_D$ and ${\tau}_P$, but ${\tau}_P$ tended to increase except for Osaka. This is because the concentration of airborne aerosols, represented by Asian dust in Northeast Asia, is decreased in both mass concentration and optical concentration. However, even though the mass concentration of pollution particles generated by human activity tends to decrease, Which means that the optical concentration represented as aerosol optical depth is increasing in Northeast Asia.

• Journal of Korean Society for Atmospheric Environment
• /
• v.34 no.3
• /
• pp.493-507
• /
• 2018

Due to high spatio-temporal variability of amount and optical/microphysical properties of atmospheric aerosols, satellite-based observations have been demanded for spatiotemporal monitoring the major aerosols. Observations of the heavy aerosol episodes and determination on the dominant aerosol types from a geostationary satellite can provide a chance to prepare in advance for harmful aerosol episodes as it can repeatedly monitor the temporal evolution. A new geostationary observation sensor, namely the Advanced Himawari Imager (AHI), onboard the Himawari-8 platform, has been observing high spatial and temporal images at sixteen wavelengths from 2016. Using observed spectral visible reflectance and infrared brightness temperature (BT), the algorithm to find major aerosol type such as volcanic ash (VA), desert dust (DD), polluted aerosol (PA), and clean aerosol (CA), was developed. RGB color composite image shows dusty, hazy, and cloudy area then it can be applied for comparing aerosol detection product (ADP). The CALIPSO level 2 vertical feature mask (VFM) data and MODIS level 2 aerosol product are used to be compared with the Himawari-8/AHI ADP. The VFM products can deliver nearly coincident dataset, but not many match-ups can be returned due to presence of clouds and very narrow swath. From the case study, the percent correct (PC) values acquired from this comparisons are 0.76 for DD, 0.99 for PA, 0.87 for CA, respectively. The MODIS L2 Aerosol products can deliver nearly coincident dataset with many collocated locations over ocean and land. Increased accuracy values were acquired in Asian region as POD=0.96 over land and 0.69 over ocean, which were comparable to full disc region as POD=0.93 over land and 0.48 over ocean. The Himawari-8/AHI ADP algorithm is going to be improved continuously as well as the validation efforts will be processed by comparing the larger number of collocation data with another satellite or ground based observation data.

• Journal of Korean Society for Atmospheric Environment
• /
• v.14 no.5
• /
• pp.465-478
• /
• 1998

In this study, seasonal variations of the dry deposition velocity and deposition flux for the sulfur dioxide were analysed. The field observation was performed during one year (from November 1, 1995 to October 31, 1996) in Chunchon basin. The turbulence data were measured by 3-dimensional sonic anemometer/thermometer, and were estimated by mean meteorological data obtained at two heights (2.5 m and 10 m) of meteorological tower. Also, the estimation methods were evaluated by comparing the turbulence data. The results showed that the estimated dry deposition velocity and turbulence parameter such as uc and sensible heat flux using mean meteorological data were relatively similar to the sonic measurements, but all showed somewhat large differences. The dry deposition velocity was large in summer and small in winter mainly due to canopy resistance (rc). The major factor which affects diurnal variation of the velocity was aerodynamic resistance (rw). The SO2 dry deposition flux was large in winter and small in summer in Chunchon.

• Journal of Korean Society for Atmospheric Environment
• /
• v.11 no.3
• /
• pp.253-262
• /
• 1995

A study has been performed on the characteristics of rural and urban surface ozone concentration for the period of March 1992 to February 1993. The monitoring station of rural ozone is located at Kosan, Cheju and other urban monitoring stations are located at Seoul, Pusan and Kwangju. Rural's and urban's ozone data exhibit a distinct features in many ways. First, annual mean of rural ozone concentration os very high(42 ppbv) but urban's are very low(10 .sim.15 ppbv). Second, rural ozone data shows a seasonal variation with it's maximum in spring, and minimum in summer, but urban's show a seasonal variation with it's maximum in spring, and minimum in winter. Third, diurnal variation of rural data is very small but that of urban's are very large. Fourth, urban's data are extremely low(< 3 ppbv) and have no seasonal variations.

• Journal of Korean Society for Atmospheric Environment
• /
• v.15 no.6
• /
• pp.813-826
• /
• 1999

To understand the present status of air pollutant emission data for the greater Seoul area, existing air pollutant emission data were analyzed and compared. For the criteria pollutants, estimation methods of emissions from point, line, and area sources adopted in the previous studies were analyzed and their results were compared. Two sets of VOC emission estimation were also compared and analyzed. There exists a large discrepancy among previous emission data due to the differences in the scope of emission sources and the estimation method including emission factors employed in each estimation. Applications of previous air pollutant emission studies for air quality modeling and related problems were discussed.

• Journal of Korean Society for Atmospheric Environment
• /
• v.22 no.6
• /
• pp.821-830
• /
• 2006

To identify the effect of local air pollutants on the $PM_{2.5}$ level at Gosan, $PM_{2.5}$ composition data, continuous $O_3,\;NO_x,\;SO_2,\;CO$ data, VOCs data, surface wind characteristics, and backward trajectory analysis results were analyzed for the measurements in March 2000 during which high concentrations of mass and anthropogenic ionic species were reported. It was found that the combination of surface wind and continuous gaseous species data can help to identify local effect in Jeju Island. Even in a high $PM_{2.5}$ level case mainly affected by long range transport from China, it was Identified that local effects were also significant for both the duration and pollutants' levels.

• Journal of Environmental Science International
• /
• v.18 no.7
• /
• pp.781-796
• /
• 2009

The current standard level of Heat Health Watch Warning System consider both daily maximum temperature and daily maximum heat index(HI), but current standard could not consider daily maximum HI due to the difficulties in forecasting when we consider both daily maximum temperature and daily maximum HI and no considering HI because relative humidity could not observed for some regions. So, Newly established standard level of Heat Health Watch Warning System is based on daily maximum temperature exceeding $30^{\circ}C$ for two consecutive days or daily minimum temperature exceeding $25^{\circ}C$ and daily maximum temperature exceeding $30^{\circ}C$. These days are called "extreme heat days". On extreme heat days, the standard of extreme heat advisory is based on daily maximum temperature among exceeding $32.7^{\circ}C$ and not exceeding $34.8^{\circ}C$, and extreme heat warning is based on daily maximum temperature exceeding $34.8^{\circ}C$. ANOVA analysis was carried out using the data of Seoul Metropolitan City in 1994 to check the robustness of the new standard level of Heat Health Watch Warning System from this study, in particular for mortality variable. The results reveal that the new standard specifies excess mortality well, showing significance level of 0.05 in the difference of excess mortality for each phase.

• Journal of Environmental Science International
• /
• v.19 no.7
• /
• pp.917-929
• /
• 2010

This paper aims to find out the statistical characteristics of the weather related railroad accidents and incidents. Data from Korea Railroad Operation Information System(KROIS) and Korea Railroad Accidents reports during 1996-2008 were used to investigate the occurrence frequency of railroad accidents and operation obstacles and their association with weather phenomena. The results are as follows; The occurrence frequency of railroad accidents and operation obstacles decrease gradually, and most of railroad accidents is a railroad traffic accidents. The amount of damages by a railroad weather-related accidents is higher than those of the railroad accidents and operation obstacles. It was also found that weather events influencing the railroad weather-related accidents and incidents are rainfall, snowfall, lightning, winds. And they caused a railroad weather-related accidents and incidents, such as railway obstruction, signal failure, and power supply failure. Therefore we need research about threshold review and a quantitative and qualitative analysis of a railroad weather-related accidents and incidents according to climate change.

• Journal of Environmental Science International
• /
• v.29 no.7
• /
• pp.715-727
• /
• 2020

It is well known that atmospheric environments, including both meteorology and air quality, significantly affect public health, such as chronic lung disease and cancer, and respiratory infections. In this study, we have analyzed correlations between the number of daily respiratory outpatients and the atmospheric environments data for about ten years for the city of Busan, South Korea. The respiratory problem patients data have been categorized into two health-vulnerable groups by age over 65(DayPA_O65) and under 20(DayPA_U20), each of which shows relatively higher correlations with air quality and meteorology, respectively. However, time series analysis with factor separation results in that DayPA_O65 and DayPA_U20 show a higher relation with variance components and daily irregular factors of atmospheric concentrations, respectively.

• Journal of Korean Society for Atmospheric Environment
• /
• v.20 no.1
• /
• pp.17-31
• /
• 2004

The subway play an important part in serious traffic problems. However, because subway system is a closed environment, many serious air pollution problems occurred in subway stations and injured passenger's health. Therefor, it is a necessary to identify sources and to estimate pollutant sources in order to protect passenger's health and to keep clean subway environment. The purpose of this study was to analyze a air quality in the subway stations and to apply a new receptor methodology for quantitatively estimate of PM10 sources. In this study, the size distributions of particulate matters has been measured by using Aerosizer LD (U.S.A., API, Inc.). It's real time measurement capability of time-of-flight technique offers a significant advantage of user convenience and air pollution management. Also, the mass concentrations of PM 10 has been measured by using mini-vol portable sampler (U.S.A., Airmetrics Co.). The sampling performed in Seoul subway stations during the period of February 2000 and April 2000. The number distribution data used in this study consisted of 26 raw data sets in the Jongno-sam-ga station. Correlation Analysis can be used in subway stations for source separation and identification. Then, number contribution from each source is determined by the particle number balance (PNB). The mass concentration data used in this study consisted of 31 raw data in the 8 different stations. The mass contributions of PM10 sources in the concourse by using PMF/CMB model.