• Journal of Korean Society for Atmospheric Environment
• /
• v.32 no.4
• /
• pp.435-447
• /
• 2016

Anthropogenic emissions of $PM_{2.5}$ in Chuncheon are considered to be low according to the national emissions inventory; however, the atmospheric $PM_{2.5}$ concentrations have been reported to be higher than or at least similar to those measured in metropolitan (e.g. Seoul) and/or in industrial cities (e.g. Incheon, Ulsan). In this study, the concentrations of $PM_{2.5}$ and its ionic and carbonaceous compounds were measured from Jan. 2013 to Dec. 2014 in Chuncheon, Korea to identify the characteristics of high $PM_{2.5}$ concentration event. Average $PM_{2.5}$ concentration was $34.6{\mu}g/m^3$, exceeding the annual air quality standard ($25{\mu}g/m^3$). The most abundant compound was organic carbon (OC), comprising 26% of $PM_{2.5}$ mass, followed by $SO_4{^{2-}}$. Among 14 high concentration events, three events showed clearly enhanced contributions of OC, $SO_4{^{2-}}$, $NO_3{^-}$ and $NH_4{^+}$ to $PM_{2.5}$ under the fog events. One event observed in summer showed high concentration of $SO_4{^{2-}}$ while the high wind speeds and the low $PM_{2.5}/PM_{10}$ ratios were observed for the two high concentration events. These results indicate that the secondary aerosol formation under the fog events and high atmospheric temperature as well as the regional and/or the long-range transport were important on enhancing $PM_{2.5}$ concentration in Chuncheon. Cluster analysis based on back trajectories also suggested the significant impacts of regional transport from China and metropolitan areas of Korea on $PM_{2.5}$ in Chuncheon.

• Journal of Korean Society for Atmospheric Environment
• /
• v.29 no.5
• /
• pp.642-655
• /
• 2013

In this study, semi-continuous measurements of $PM_{2.5}$ mass, organic and elemental carbon (OC and EC), black carbon (BC), and ionic species concentrations were made for the period of April 03~13, 2012, at a South Area Supersite at Gwangju. Possible sources causing the high concentrations of major chemical species in $PM_{2.5}$ observed during a haze episode were investigated. The measurement results, along with meteorological parameters, gaseous pollutants data, air mass back trajectory analyses and PSCF (potential source contribution function) results, were used to study the haze episode. Substantial enhancements of OC, EC, BC, $K^+$, $SO{_4}^{2-}$, $NO{_3}{^-}$, $NH{_4}{^+}$, and CO concentrations were closely associated with air masses coming from regions of forest fires in southeastern China, suggesting likely an impact of the forest fires. Also the PSCF maps for EC, OC, $SO{_4}^{2-}$, and $K^+$ demonstrate further that the long-range transport of smoke plumes of forest fires detected over the southeastern China could be a possible source of haze phenomena observed at the site. Another possible source leading to haze formation was likely from photochemistry of precursor gases such as volatile organic compounds, $SO_2$, and $NO_2$, resulting in accumulation of secondary organic aerosol, $SO{_4}^{2-}$ and $NO{_3}{^-}$. Throughout the episode, local wind directions were between 200 and $230^{\circ}C$, where two industrial areas are situated, with moderate wind speeds of 3~5 m/s, resulting in highly elevated concentration of $SO_2$ with a maximum of 15 ppb. The $SO{_4}^{2-}$ peak occurring in the afternoon hours coincided with maximum ambient temperature ($24^{\circ}C$) and ozone concentration (~100 ppb), and were driven by photochemistry of $SO_2$. As a result, the pattern of $SO{_4}^{2-}$ variations in relation to wind direction, $SO_2$ and $O_3$ concentrations, and the strong correlation between $SO_2$ and $SO{_4}^{2-}$ ($R^2=0.76$) suggests that in addition to the impact of smoke plumes from forest fires in the southeastern China, local $SO_2$ emissions were likely an important source of $SO{_4}^{2-}$ leading to haze formation at the site.

• Atmosphere
• /
• v.29 no.4
• /
• pp.429-438
• /
• 2019

Organic carbon (OC) and elemental carbon (EC) in PM_2.5 were measured with Sunset Laboratory Model-5 Semi-Continuous OC/EC Field Analyzer by NIOSH/TOT method at Anmyeondo Global Atmosphere Watch (GAW) Regional Station (37°32'N, 127°19'E) in July and August, 2017. The mean values of OC and EC were 3.7 ㎍ m^-3 and 0.7 ㎍ m^-3, respectively. During the study period, the concentrations of reactive gases and aerosol compositions were evidently lower than those of other seasons. It is mostly due to meteorological setting of the northeast Asia, where the influence of continental outflow is at its minimum during this season under southwesterly wind. While the diurnal variation of OC and EC were not clear, the concentrations of O₃, CO, NOx, EC, and OC were evidently enhanced under easterly wind at night from 20:00 to 8:00. However, the high concentration of EC was observed concurrently with CO and NOx under northerly wind during 20:00~24:00. It indicates the influence of thermal power plant and industrial facilities, which was recognized as a major emission source during KORUS-AQ campaign. The diurnal variations of pollutants clearly showed the influence of land-sea breeze, in which OC showed good correlation between EC and O₃ in seabreeze. It is estimated to be the recirculation of pollutants in land-sea breeze cycle. This study suggests that in general, Anmyeondo station serves well as a background monitoring station. However, the variation in meteorological condition is so dynamic that it is primary factor to determine the concentrations of secondary species as well as primary pollutants at Anmyeondo station.

• Journal of Korean Society for Atmospheric Environment
• /
• v.32 no.3
• /
• pp.320-328
• /
• 2016

Among biogenic volatile organic compounds (BVOCs) in the natural ecosystem, monoterpenes, along with isoprene, play important roles in atmospheric chemistry and make significant impacts on air pollution and climate change, especially due to their contribution to secondary organic aerosol production and photochemical ozone formation. It is essential to measure monoterpene concentrations accurately for understanding their oxidation processes, emission processes and estimation, and interactions between biosphere and atmosphere. Thus, traceable calibration standards are crucial for the accurate measurement of monoterpenes at ambient levels. However, there are limited information about developing calibrations standards for monoterpenes in pressured cylinders. This study describes about developing primary standard gas mixtures (PSMs) for monoterpenes at about 2 nmol/mol, near ambient levels. The micro-gravimetric method was applied to prepare monoterpene (${\alpha}$-pinene, 3-carene, R-(+)-limonene, 1,8-cineole) PSMs at $10{\mu}mol/mol$ and then the PSMs were further diluted to 2 nmol/mol level. To select an optimal cylinder for the development of monoterpene PSMs, three different kinds of cylinders were used for the preparation and were evaluated for uncertainty sources including long-term stability. Results showed that aluminum cylinders with a special internal surface treatment (Experis) had little adsorption loss on the cylinder internal surface and good long-term stability compared to two other cylinder types with no treatment and a special treatment (Aculife). Results from uncertainty estimation suggested that monoterpene PSMs can be prepared in pressured cylinders with a special treatment (Experis) at 2 nmol/mol level with an uncertainty of less than 4%.

• Journal of Korean Society for Atmospheric Environment
• /
• v.33 no.4
• /
• pp.411-423
• /
• 2017

The spacial potential source contribution function (PSCF) method was utilized by considering topography and height of back trajectories based on the measurement of organic typo matter (OM), $NO_3{^-}$, $SO{_4}^{2-}$, and $NH_4{^+}$ at the Baegryungdo Super Site ($37^{\circ}57^{\prime}N$, $124^{\circ}37^{\prime}E$, 135 m a.s.l. (above sea level)) for three selected periods (i.e., January~April, May~August, and September~December) in 2013. The PSCF were calculated on the contributions of trans-boundary transport to the hourly mean concentrations using a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). The cluster analysis using back trajectories was performed to identify the major airflows to the sampling site. The upper atmosphere in the Tianjin area of China and the lower atmosphere in the western coast area of Korea can be the major source of trans-boundary pollution to the sampling site during January~April resulted from PSCF. The area in Lianyungang-city and Liaoning-sheng, China can be responsibile for the nitrogen related secondary compounds during May~August, and Shandong Peninsula in China is the major source area during September~December. In addition, relationships between the cluster analysis of back trajectories and PSCF were investigated for the statistically significance level for the source areas.

• Analytical Science and Technology
• /
• v.29 no.5
• /
• pp.209-218
• /
• 2016

PM₁₀ and PM_2.5 samples were collected at the 1100 site of Mt. Halla in Jeju Island during 2011~2012, and their ionic and elemental species were analyzed, in order to investigate the characteristics of emission sources as well as aerosol compositions. The mass concentrations of PM₁₀ and PM_2.5 were 22.0±13.1 µg/m³ and 11.3±6.1 µg/m³, respectively, showing 2.4~2.6 times lower than those of the capital city area of Korea. The composition ratios of major secondary pollutants (nss-SO₄²⁻, NH₄⁺, and NO₃⁻) were the highest as 85.5 % for PM₁₀ and 91.3 % for PM_2.5, and followed by the order of marine (Na⁺, Cl⁻, and Mg²⁺), organic acid (HCOO⁻ and CH₃COO⁻), and soil (nss-Ca²⁺) sources. Among the elemental species in PM₁₀, soil-originated components (Al, Fe, and Ca) were consisted of 50.9 %, which was higher proportion than marine and anthropogenic elements. The acidification of the fine particulate matters was found to be influenced mostly by sulfuric and nitric acids, and these acids were mainly neutralized by calcium carbonate in PM₁₀ and by ammonia in PM_2.5. The clustered back trajectories showed that 47 % of total air mass inflows was from the China, and the concentrations of NO₃⁻ and nss-Ca²⁺ were especially high corresponding to the inflows.