Lim-Seok Chang

Identifying airborne fungi in Seoul, Korea using metagenomics

Fungal spores are widespread and common in the atmosphere. In this study, we use a metagenomic approach to study the fungal diversity in six total air samples collected from April to May 2012 in Seoul, Korea. This springtime period is important in Korea because of the peak in fungal spore concentration and Asian dust storms, although the year of this study (2012) was unique in that were no major Asian dust events. Clustering sequences for operational taxonomic unit (OTU) identification recovered 1,266 unique OTUs in the combined dataset, with between 223᾿96 OTUs present in individual samples. OTUs from three fungal phyla were identified. For Ascomycota, Davidiella (anamorph: Cladosporium) was the most common genus in all samples, often accounting for more than 50% of all sequences in a sample. Other common Ascomycota genera identified were Alternaria, Didymella, Khuskia, Geosmitha, Penicillium, and Aspergillus. While several Basidiomycota genera were observed, Chytridiomycota OTUs were only present in one sample. Consistency was observed within sampling days, but there was a large shift in species composition from Ascomycota dominant to Basidiomycota dominant in the middle of the sampling period. This marked change may have been caused by meteorological events. A potential set of 40 allergyinducing genera were identified, accounting for a large proportion of the diversity present (22.5᾿7.2%). Our study identifies high fungal diversity and potentially high levels of fungal allergens in springtime air of Korea, and provides a good baseline for future comparisons with Asian dust storms.

Time-resolved measurements of PM2.5 carbonaceous aerosols at Gosan, Korea.

ABSTRACT In order to better understand the characteristics of atmospheric carbonaceous aerosol at a background site in Northeast Asia, semicontinuous organic carbon (OC) and elemental carbon (EC), and time-resolved water-soluble organic carbon (WSOC) were measured by a Sunset OC/EC and a PILS-TOC (particle-into-liquid sampler coupled with an online total organic carbon) analyzer, respectively, at the Gosan supersite on Jeju Island, Korea, in the summer (May 28–June 17) and fall (August 24–September 30) of 2009. Hourly average OC concentration varied in the range of approximately 0.87–28.38 μgC m−3, with a mean of 4.07 ± 2.60 μgC m−3, while the hourly average EC concentration ranged approximately from 0.04 to 8.19 μgC m−3, with a mean of 1.35 ± 0.71 μgC m−3, from May 28 to June 17, 2009. During the fall season, OC varied in the approximate range 0.9–9.6 μgC m−3, with a mean of 2.30 ± 0.80 μgC m−3, whereas EC ranged approximately from 0.01 to 5.40 μgC m−3, with a mean of 0.66 ± 0.38 μgC m−3. Average contributions of EC to TC and WSOC to OC were 26.0% ± 9.7% and 20.6% ± 7.4%, and 37.6% ± 23.5% and 57.2% ± 22.2% during summer and fall seasons, respectively. As expected, clear diurnal variation of WSOC/OC was found in summer, varying from 0.22 during the nighttime up to 0.72 during the daytime, mainly due to the photo-oxidation process. In order to investigate the effect of air mass pathway on the characteristics of carbonaceous aerosol, 5-day back-trajectory analysis was conducted using the HYSPLIT model. The air mass pathways were classified into four types: Continental (CC), Marine (M), East Sea (ES) and Korean Peninsula (KP). The highest OC/EC ratio of 3.63 was observed when air mass originated from the Continental area (CC). The lowest OC/EC ratio of 0.79 was measured when air mass originated from the Marine area (M). A high OC concentration was occasionally observed at Gosan due to local biomass burning activities. The contribution of secondary OC to total OC varied approximately between 8.4% and 32.2% and depended on air mass type. IMPLICATIONS Organic material contributes approximately 20–90% of the total fine particulate mass concentration at different sites over the world depending on location and season. Organic carbon consists of hundreds of compounds with a wide range of chemical and optical properties. A better understanding of the chemical characteristics of carbonaceous aerosol influenced by increasing anthropogenic pollution in the downwind regions of the East Asian continent is needed in order to determine their impacts on regional air quality and climate change.

Human-model hybrid Korean air quality forecasting system

ABSTRACT The Korean national air quality forecasting system, consisting of the Weather Research and Forecasting, the Sparse Matrix Operator Kernel Emissions, and the Community Modeling and Analysis (CMAQ), commenced from August 31, 2013 with target pollutants of particulate matters (PM) and ozone. Factors contributing to PM forecasting accuracy include CMAQ inputs of meteorological field and emissions, forecasters’ capacity, and inherent CMAQ limit. Four numerical experiments were conducted including two global meteorological inputs from the Global Forecast System (GFS) and the Unified Model (UM), two emissions from the Model Intercomparison Study Asia (MICS-Asia) and the Intercontinental Chemical Transport Experiment (INTEX-B) for the Northeast Asia with Clear Air Policy Support System (CAPSS) for South Korea, and data assimilation of the Monitoring Atmospheric Composition and Climate (MACC). Significant PM underpredictions by using both emissions were found for PM mass and major components (sulfate and organic carbon). CMAQ predicts PM2.5 much better than PM10 (NMB of PM2.5: -20~-25%, PM10: -43~-47%). Forecasters’ error usually occurred at the next day of high PM event. Once CMAQ fails to predict high PM event the day before, forecasters are likely to dismiss the model predictions on the next day which turns out to be true. The best combination of CMAQ inputs is the set of UM global meteorological field, MICS-Asia and CAPSS 2010 emissions with the NMB of -12.3%, the RMSE of 16.6μ/m3 and the R2 of 0.68. By using MACC data as an initial and boundary condition, the performance skill of CMAQ would be improved, especially in the case of undefined coarse emission. A variety of methods such as ensemble and data assimilation are considered to improve further the accuracy of air quality forecasting, especially for high PM events to be comparable to for all cases. Implications: The growing utilization of the air quality forecast induced the public strongly to demand that the accuracy of the national forecasting be improved. In this study, we investigated the problems in the current forecasting as well as various alternatives to solve the problems. Such efforts to improve the accuracy of the forecast are expected to contribute to the protection of public health by increasing the availability of the forecast system.

Semi-continuous Measurements of PM 2.5 OC and EC at Gosan: Seasonal Variations and Characteristics of High-concentration Episodes

At Gosan ABC superstation in Jeju Island, we measured organic carbon (OC) and elemental carbon (EC) in from October 2009 to June 2010 using a Sunset Laboratory Model-4 Semi-Continuous OC/EC Field Analyzer. It employs TOT (Thermal-Optical-Transmittance) method with NIOSH 5040 protocol and enables to continuously monitor OC and EC concentrations with 1-hour time resolution. The mean values of OC and EC for the entire period of measurements were and , respectively. The OC/EC ratio was 3 and EC accounted of total carbon (TC, TC

Chemical characteristics of long-range-transported fine particulate matter at Gosan, Jeju Island, in the spring and fall of 2008, 2009, 2011, and 2012

Carbonaceous species (organic carbon [OC] and elemental carbon [EC]) and inorganic ions of particulate matter less than 2.5 μm (PM2.5) were measured to investigate the chemical characteristics of long-range-transported (LTP) PM2.5 at Gosan, Jeju Island, in Korea in the spring and fall of 2008–2012 (excluding 2010). On average, the non-sea-salt (nss) sulfate (4.2 µg/m3) was the most dominant species in the spring, followed by OC (2.6 µg/m3), nitrate (2.1 µg/m3), ammonium (1.7 µg/m3), and EC (0.6 µg/m3). In the fall, the nss-sulfate (4.7 µg/m3) was also the most dominant species, followed by OC (4.0 µg/m3), ammonium (1.7 µg/m3), nitrate (1.1 µg/m3), and EC (0.7 µg/m3). Both sulfate and OC were higher in the fall than in the spring, possibly due to more common northwest air masses (i.e., coming from China and Korea polluted areas) and more frequent biomass burnings in the fall. There was no clear difference in the EC between the spring and fall. The correlation between OC and EC was not strong; thus, the OC measured at Gosan was likely transported across a long distance and was not necessarily produced in a manner similar to the EC. Distinct types of LTP events (i.e., sulfate-dominant LTP versus OC-dominant LTP) were observed. In the sulfate-dominant LTP events, air masses directly arrived at Gosan without passing over the Korean Peninsula from the industrial area of China within 48 hr. During these events, the aerosol optical depth (AOD) increased to 1.63. Ionic balance data suggest that the long-range transported aerosols are acidic. In the OC-dominant LTP event, a higher residence time of air masses in Korea was observed (the air masses departing from the mainland of China arrived at the sampling site after passing Korea within 60–80 hr). Implications: In Northeast Asia, various natural and anthropogenic sources contribute to the complex chemical components and affect local/regional air quality and climate change. Chemical characteristics of long-range-transported (LTP) PM2.5 were investigated during spring and fall of 2008, 2009, 2011, and 2012. Based on air mass types, sulfate-dominant LTP and OC-dominant LTP were observed. A long-term variation and chemical characteristics of PM2.5 along with air mass and satellite data are required to better understand long-range-transported aerosols.

Monitoring atmospheric composition by GEO-KOMPSAT-1 and 2: GOCI, MI and GEMS

With the launch of Geostationary Ocean Color Imager(GOCI) and Meteorological Imager(MI) onboard the Communication, Oceanography, and Meteorology Satellite(COMS) in 2010, hourly monitoring of various aerosol properties has been realized. Together with the plan to launch Geostationary Environment Monitoring Spectrometer(GEMS) in 2019, monitoring of trace gas concentration will be possible in high temporal and spatial resolution. In this study, results and plan to monitor atmospheric composition from geostationary earth orbit(GEO) are presented.

Analysis of the Recent Trend of National Background PM 10 Concentrations over Korea, China, and Japan

The goal of this research is to examine the recent decade-long (2000~2014) trends of national background concentrations over China, Japan, and Korea. Based on the Long-range Transboundary Air Pollutants in Northeast Asia (LTP) project, which is three-party collaboration project among three countries, we investigated the long-term trends of national background PM10 concentrations in three countries over the recent 15 years, including the 2008 Beijing Olympic Game period. In accordance with the agreement among three countries, a total of 8 national background sites: three national background monitoring sites in China (2 sites in Dalian, and 1 in Xiamen), three sites in Korea (Ganghwa, Gosan, and Taean), and two sites in Japan (Oki and Rishiri), were chosen for the trend analysis. The results showed that Chinese background concentration recorded the highest level overall. However, the rapid declining recent trends of annual median (50-percentile) values were surprisingly detected since 2006 or 2007 in every site in China, with the most rapidly decreasing rate (-18.6±10.3%/year) over 2006~2007, and the second most rapidly decreasing rate (-18.0±1.5%/year) over 2007~2008. Based on the previous statistical literature, we concluded that this declining trends were due to the emission reduction of PM10 concentrations in China for 2008 Beijing Olympic Game. In Korea, Ganghwa was also showing the decreasing trends over the recent years since 2006, which is also well accorded with the decreasing period of Chinese background concentrations. Taean also implied some impact of Beijing Olympic Game, showing small but detectable decreasing trends, while Gosan showed the increasing tendencies probably due to the near-urban influences. However, since 2012, most sites in both China and Korea showed strong increasing trends, undoubtedly implying the increasement of both emission in 한·중·일 PM10 국가 배경농도 최근 경향 분석 361 J. Korean Soc. Atmos. Environ., Vol. 32, No. 4, 2016 1. 서 론 대기오염물질 배경농도란 대상 지역에서의 자체 인 위적 오염 발생원의 영향을 배제하여 자연적 배출량만 을 고려한 농도 수준으로서, 대상 지역의 자체 인위적 배출량을 최소화하였을 때 기대할 수 있는 대기오염물 질의 농도를 말한다 (Nopmongcol et al., 2016; EPA, 2014). 이때 대상 지역을 특정 지역 (혹은 국가)으로 특 정할 경우에 해당하는 지역 (국가) 배경농도는 인위적 오염물질이 아닌 자연적으로 배출되는 배출량뿐만 아 니라 장거리 수송되어 오는 농도까지 고려하는 농도이 므로, 풍상측 지역에서의 자연적 및 인위적 배출량의 영향을 모두 고려하는 개념으로 정의한다 (EPA, 2014; McKendry, 2006). 따라서 어느 지역 (국가)에서의 오염 물질 농도 감축을 위한 계획을 수립하는 것은 해당 지 역의 인위적인 활동으로 인해 발생하는 대기오염물질 의 기여도를 줄이는 것이 목표이므로, 예컨대 우리나 라의 PM10 농도의 감축을 위한 계획을 수립하고 결과 를 평가할 경우, PM10 배경농도를 파악하는 것은 국내 의 현실적인 PM10 규제 목표를 설정하고 평가할 때 중 요한 기준이 될 수 있다. 전 세계적으로 배경농도 분석에 대한 연구는 다양한 물질에 대하여 활발히 수행되어졌다. 한반도에서도 Rd, CFC, SO2, NO, O3, 미세먼지 등 여러 물질에 대한 배 경농도 측정 및 분석 또한 현재 수행되고 있으나 (Ko et al., 2014; Kang et al., 2012; Kim et al., 2001; Park et al., 1994; Kim et al., 1992), 특정 지점에서 단기 측정 값을 분석한 경우가 많은 편이라 한 지점에서 10년 이 상의 장기간의 추세에 대한 연구는 부족한 실정이다. 우리나라는 지정학적으로 중국 산둥 반도와 약 400 km 정도밖에 되지 않아, 동북아시아 지역의 가장 큰 오염물질 배출지역인 중국의 풍하측에 자리 잡고 있으 므로 편서풍을 타고 대륙으로부터 불어오는 황사와 같 은 자연배출량뿐만 아니라 중국에서 배출되는 인위적 인 배출량의 영향을 크게 받고 있어 이에 대한 영향 연구는 자주 보고되었다 (Choi et al., 2014; Lee et al., 2014; Park et al., 2012). 따라서 국내의 배출 규제와 목 표 수준을 논의하기 위해서는 국내 자체 배출량 규제 뿐만 아니라 국가 간 장거리 이동에 의한 월경성 대기 오염물질의 영향을 필수적으로 논의하여야 하므로 주 변 국가를 포함한 동북아시아 국가 배경농도에 대한 이해가 매우 필요하였다. 이에 따라 1990년대 이후 현 재까지 한·중·일 3국 정부 간 협의 하에 대기오염물 질 공동연구체계인 Long-range Transboundary Air Pollutants in Northeast Asia 사업 (이하 ‘LTP 사업’으로 명 명)이 발주되어 대기오염물질의 장거리 이동에 관한 국가 간 공동연구가 매우 오랫동안 진행되어 왔다. 특 히 대기오염물질의 장거리 이동에 관한 한·중·일 협 력 연구 중 대기오염물질들의 배출원-수용지 관계 (Source-Receptor Relationship)에 대한 모델링 연구는 3국 간 LTP 사업의 주요 이슈로 평가되고 있으며 (NIER, 2012a), 이와 연관된 측정 분석적 연구 또한 각 국가 배경농도 측정 지점들이 협의되어 국가별 배경농 도의 측정 분석적 연구가 병행되어 왔다. 본 연구에서 는 동북아시아 LTP 사업을 통해 수집된 한·중·일 국 가별 배경농도 측정소에서 2000년~2014년 측정된 미 세먼지 배경농도를 분석하여 그 경향성 및 계절적 특 성 등을 다양하게 분석하였다.

Behavior of air particles associated with atmospheric recirculation over complex coastal area

Several numerical experiments were carried out over Gwangyang Bay area, which is located southwestern part of the Korean Peninsula, to clarify the characteristics of the recirculation potential and the impact of the spatial size of the model domain on air pollutant dispersion. The numerical models used in this study were Weather and Research Forecasting (WRF) model to assess the atmospheric circulation and FLEXPART to estimate the level of pollutant dispersion. Regardless of the synoptic conditions, the variation in the recirculation potential based on the transported distance of air pollutants agreed well with the change in ozone concentration. Weak synoptic wind and strong regional flow results in the highest recirculation potential in both inland and coastal areas. The concentration in limited areas is strongly associated with the pollutants recirculated by regional circulation. The persistence of synoptic wind often prevents particle recirculation but intensified regional circulation around coastal area is favorable for increasing the returning particles. Therefore, the determined domain size should be large enough to include the trace of recirculated pollutants when weak synoptic wind occurs.

The Effect of 2008 Beijing Olympic on Korean Air Quality

This study aims to identify the impacts of air quality in the Korean Peninsula according to the Chinas environmental policies in preparation of the Beijing 2008 Olympic Games. The measurement of emission variations in China, aircraft measurement, and modelling were carried out. The reduction measures in Beijing, China and its emission changes resulted in in decrease out of the total emissions within the Beijing region, whereas when it comes to the whole nation of China, the reduction rate was about . Comparing the concentration of the air pollutants in Seoul and Ganghwa in August 2008 during around the period of Beijing Olympic Games with one in showed that the concentrations in the past was above 5ppb, while the concentration in the 2008 olympic period was 4ppb and below. The NOx at the Seokmori site in Ganghwa tended to be lower in concentration in 2008 than in between . As for and , the concentration tended to be rather low since August 11. The air current track that showed during the period of aircraft measurement presented to be flowed into Korea through the Northeast part of China and the coast of Bohai Bay, while the concentrations of . NOx, and over the west sea on August 20 and 24 were 0.54 (0.28ppb), 0.86 (1.84ppb), and 54.0 (41.5ppb) respectively, similar or lower than the ones measured in the past in the similar current patterns. The modelling result showed similar patterns to the data of aircraft measurement, in particular in . Overall, the reduction measures in Beijing, China affected directly and indirectly the air quality in the Korean peninsular, but the impact was not significant as it was momentary and limited to the intended area.