• 한국대기환경학회지
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• 제27권5호
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• pp.603-613
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• 2011

The collection of $PM_{10}$ and $PM_{2.5}$ samples was made at Gosan site of Jeju Island. Their ionic compositions of both inorganic and organic phases were then analyzed to examine their acidification and neutralization characteristics in atmospheric aerosols. The mass concentrations of $PM_{10}$ and $PM_{2.5}$ at Gosan site were $37.6{\pm}20.1$ and $22.9{\pm}14.3{\mu}g/m^3$, respectively, showing the content ratio of $PM_{2.5}$ to $PM_{10}$ as 61.0%. In the evaluation of ionic balance, the correlation coefficients (r) between the sums of cationic and anionic equivalent concentrations were excellent with 0.982 ($PM_{10}$) and 0.991 ($PM_{2.5}$). The concentration ratios of $PM_{2.5}/PM_{10}$ derived for nss-$SO_4^{2-}$, $NO_3^-$, and $NH_4^+$ were 0.94, 0.56, and 1.02, respectively, indicating the relative dominance of fine fractions. The acidifying capacity of inorganic anions ($SO_4^{2-}$ and $NO_3^-$) in $PM_{10}$ and $PM_{2.5}$ were 96.5% and 97.3%, while those of organic anions ($HCOO^-$ and $CH_3COO^-$) in each fraction were 2.9% and 2.0%, respectively. On the other hand, the neutralizing capacity of $PM_{10}$ and $PM_{2.5}$ by $NH_3$ were 72.8% and 82.3%, while their $CaCO_3$ counter parts were 22.5% and 13.3%, respectively.

• 한국입자에어로졸학회지
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• 제13권2호
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• pp.97-104
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• 2017

In order to characterize atmospheric aerosols in Chungcheong area, black carbon concentration, which is known to be closely related to global warming, was measured and compared with $PM_{10}$, $PM_{2.5}$ concentrations and various meteorological parameters such as wind velocity and wind direction. Multi Angle Absorption Photometer (MAAP), a filter-based equipment, was used for the black carbon measurement, and the $PM_{10}$, $PM_{2.5}$ concentrations, wind velocity and wind direction were provided by the local monitoring stations. Black carbon concentration was monitored to be high in spring and winter but low in fall. $PM_{10}$ concentration was observed to be high when westerly wind was strong.

• Asian Journal of Atmospheric Environment
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• 제5권4호
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• pp.237-246
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• 2011

To explore the sources of carbonaceous material in the airborne particulate matter (PM), comprehensive PM sampling was performed (3 to 14 January 2010) at a traffic hot spot site (HS), Farm Gate, Dhaka using several samplers: AirMetrics MiniVol (for $PM_{10}$ and $PM_{2.5}$) and MOUDI (for size fractionated submicron PM). Long-term PM data (April 2000 to March 2006 and April 2000 to March 2010 in two size fractions ($PM_{2.2}$ and $PM_{2.2-10}$) obtained from two air quality-monitoring stations, one at Farm Gate (HS) and another at a semi-residential (SR) area (Atomic Energy Centre, Dhaka Campus, (AECD)), respectively were also analyzed. The long-term PM trend shows that fine particulate matter concentrations have decreased over time as a result of government policy interventions even with increasing vehicles on the road. The ratio of $PM_{2.5}/PM_{10}$ showed that the average $PM_{2.5}$ mass was about 78% of the $PM_{10}$ mass. It was also found that about 63% of $PM_{2.5}$ mass is $PM_1$. The total contribution of BC to $PM_{2.5}$ is about 16% and showed a decreasing trend over the years. It was observed that $PM_1$ fractions contained the major amount of carbonaceous materials, which mainly originated from high temperature combustion process in the $PM_{2.5}$. From the IMPROVE TOR protocol carbon fraction analysis, it was observed that emissions from gasoline vehicles contributed to $PM_1$ given the high abundance of EC1 and OC2 and the contribution of diesel to $PM_1$ is minimal as indicated by the low abundance of OC1 and EC2. Source apportionment results also show that vehicular exhaust is the largest contributors to PM in Dhaka. There is also transported $PM_{2.2}$from regional sources. With the increasing economic activities and recent GDP growth, the number of vehicles and brick kilns has significantly increased in and around Dhaka. Further action will be required to further reduce PM-related air pollution in Dhaka.

• Asian Journal of Atmospheric Environment
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• 제9권4호
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• pp.280-287
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• 2015

The high time-resolution monitoring data are essential to estimate rapid changes in chemical compositions, concentrations, formation mechanisms, and likely sources of atmospheric particulate matter (PM). In this study, $PM_{2.5}$ sulfate, $PM_{2.5}$, $PM_{10}$, and the number concentration of size-resolved PMs were monitored in Fukuoka, Japan by good time-resolved methods during the springtime. The highest monthly average $PM_{2.5}$ sulfate was found in May ($8.85{\mu}g\;m^{-3}$), followed by April ($8.36{\mu}g\;m^{-3}$), March ($8.13{\mu}g\;m^{-3}$), and June ($7.22{\mu}g\;m^{-3}$). The cases exceed the Japanese central government's safety standard for $PM_{2.5}$ ($35{\mu}g\;m^{-3}$) reached 10.11% during four months campaign. The fraction of $PM_{2.5}$ sulfate to $PM_{2.5}$ varied from 12.05% to 68.11% with average value of 35.49% throughout the entire period of monitoring. This high proportion of sulfate in $PM_{2.5}$ is an obvious characteristic of the ambient $PM_{2.5}$ in Fukuoka during the springtime. However, the average fraction of $PM_{2.5}$ sulfate to $PM_{2.5}$ in three rain events occurred during our intensive campaign fell right down to 15.53%. Unusually high $PM_{2.5}$ sulfate (> $30{\mu}g\;m^{-3}$) marked on three days were probably affected by the air parcels coming from the Chinese continent, the natural sulfur in the remote marine atmosphere, and a large number of ships sailing on the nearby sea. The theoretical number concentration of $(NH_4)_2SO_4$ in $PM_{0.5-0.3}$ was originally calculated and then compared to $PM_{2.5}$ sulfate. A close resemblance between the diurnal variations of the theoretically calculated number concentration of $(NH_4)_2SO_4$ in $PM_{0.5-0.3}$ and $PM_{2.5}$ sulfate concentration indicates that the secondary formed $(NH_4)_2SO_4$ was the primary form of sulfate in $PM_{2.5}$ during our monitoring period.

• 한국환경과학회지
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• 제29권5호
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• pp.495-506
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• 2020

This study investigated the nitrate formation process, and mass closure of Particulate Matter (PM) were calculated over the urbanized area of Jeju Island. The data for eight water-soluble inorganic ions and nineteen elements in PM_2.5 and PM₁₀ were used. The results show that the nitrate concentration increased as excess ammonium increased in ammonium-rich samples. Furthermore, nitrate formation was not as important in ammonium-poor samples as it was in previous studies. According to the sum of the measured species, approximately 45~53% of gravimetric mass of PM remained unidentified. To calculate the mass closure for both PM_2.5 and PM₁₀, PM chemical components were categorized into secondary inorganic aerosol, crustal matter, sea salt, trace matter and unidentified matter. The results by the mass reconstruction of PM components show that the portion of unidentified matter was decreased from 52.7% to 44.0% in PM_2.5 and from 45.1% to 29.1% in PM₁₀, despite the exclusion of organic matter and elemental carbon.

• 한국식품영양과학회지
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• 제22권5호
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• pp.531-538
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• 1993

본 연구는 8-12세의 남녀 국민학생 각각 8명씩을 대상으로 4주간 평상시와 같은 생활양식과 식생활 환경하에서 에너지 섭취량(GE)과 체내 에너지 보류량 (BE)의 변동을 측정하므로서(에너지 평형법) 에너지 소비량을 산출하였다. 에너지 섭취량과 대변으로의 에너지 손실량(FE)은 열량계로 측정하였고 소변으로의 에너지 손실량(UE)은 질소 배설량으로부터 환산하였다. 체내 지방조직량(FM)은 피부두께를 측정하여 산출한 신체 밀도법에 의하였다. 총 에너지 섭취량에 대한 당질, 단백질 및 지방질의 구성비는 남자 아동이 각각 70.0$\pm$0.5%, 10.2$\pm$0.3% 및 19.9$\pm$0.5%이었으며 여자 아동이 각각 74.0$\pm$1.7%, 10.7$\pm$0.3%및 15.3$\pm$0. 5%이었다. 총 에너지 섭취량에 대한 대변으로의 에너지 손실율은 남자 및 여자 아동별로 각각 5.1%및 4. 5%이었다. 대변과 소변으로의 에너지 손실량을 감하여 산출한 1일 1인당 평균 대사에너지량(ME)은 남자 및 여자 아동별 각각 1862$\pm$15kca1 및 1627$\pm$20kca1 이었다. 28일 동안의 체성분 변동량으로부터 산출한 체내 총 에너지 변동량(BE)은 남자 및 여자 아동별로 각각 평균 +1524$\pm$539kcal 및 +3622$\pm$718kcal가 증가하였다. 1일 1인당 평균 에너지 소비량은 남자 아동이 1812$\pm$37kca1이고 여자 아동이 1487$\pm$25kcal로서 체중 kg당 에너지 소비량은 남자 및 여자 아동별로 각각 62 $\pm$2kcal 및 52 $\pm$2kcal이었다.

• 한국입자에어로졸학회지
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• 제18권4호
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• pp.109-127
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• 2022

Recently, low-cost particulate matter (PM) sensors have been widely used in monitoring mass concentration. Maintaining the accuracy of the sensors is important and requires rigorous performance evaluation and calibration. In this study, two commercial low-cost PM sensors(LCS), Plantower PMS3003 and Plantower PMS7003, were evaluated in the laboratory and field with a reference-grade PM monitor (GRIMM 11-D). Laboratory evaluation was conducted with single/mixed particles of PSL (Poly Styrene Latex) in an acrylic chamber at 20℃ and relative humidity of 20%. Field evaluation was conducted inside a building of Yonsei University (Shinchon) from February 12 to March 31, 2022. In both evaluations, LCS measured values became different from reference measured values when the relative humidity was high or the outdoor air PM10/PM2.5 ratio was high. Based on the field evaluation, the LCS measured values were corrected through four different regression analysis models. As a result, the multivariate polynomial regression analysis model showed highest matching with the reference PM monitor (PM2.5 >0.9, PM10 >0.85). In this model, the PM10/PM2.5 ratio and relative humidity were chosen as independent variables.

• 한국대기환경학회지
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• 제26권5호
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• pp.567-580
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• 2010

Organic carbon (OC) and elemental carbon (EC) concentrations were determined for $PM_{10}$, $PM_{2.5}$ and $PM_{1.0}$ aerosols particles collected at Gosan Superstation on Jeju Island from August 2007 to September 2008. Aerosols were collected on quartz filters for 24 hours and then OC and EC were analyzed by TOR/IMPROVED method. Mean concentrations of OC and EC were $4.66\;{\mu}g/m^3$ and $1.69\;{\mu}g/m^3$ for $PM_{10}$, $3.95\;{\mu}g/m^3$ and $1.69\;{\mu}g/m^3$ for $PM_{2.5}$, and $3.16\;{\mu}g/m^3$ and $1.42\;{\mu}g/m^3$ for $PM_{1.0}$, respectively. The concentrations of OC and EC comprised 16.4% and 6.0% of $PM_{10}$, 22.9% and 9.8% of $PM_{2.5}$, and 23.0% and 10.0% of $PM_{1.0}$. OC and EC showed a clear seasonal variation with the highest in winter and the lowest in summer. The correlations between the two were also the best during the winter ($R^2$=0.87, 0.94, and 0.95 for $PM_{10}$, $PM_{2.5}$ and $PM_{1.0}$). The ratio of OC/EC exhibited the maximum (7.24) during an Asian dust event due to an increase of OC, which was possibly derived from soil. The mass fraction of both OC and EC was the highest in fall. When OC and EC concentrations were highly elevated, EC1 (the first EC fraction determined at $550^{\circ}C$) and pyrolyzed OC (POC) were dominant subcomponents in winter and OC3 (the third OC fraction determined at $450^{\circ}C$) and POC in spring.

• 한국가축번식학회지
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• 제23권2호
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• pp.127-132
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• 1999

본 연구는 소형견 정액의 원정액과 정장제거 정액의 일반성상, 채취분획별 및 단기보존시 정자의 생존성과 아울러 동결보존시의 정자의 생존성에 대해 조사하고자 수행하였다. 1. 원정액과 정장제거 정액에 saline 및 Tris-buffer를 희석 후 각각 일반성상 검사를 실시했을 때 원정액의 경우 정자농도는 5.07$\pm$2.32$\times$$10^{6}$cells/$m\ell$, 정자의 운동성은 95.42$\pm$2.65%, 기행정자수는 4.42$\pm$0.15%로 나타났으며, RSP(saline 및 Tris-buffer)군의 경우 정자농도는 4.69$\pm$3.27~4.25$\pm$3.65$\times$$10^{6}$cells/$m\ell$, 정자의 운동성은 91.17$\pm$3.85~88.52$\pm$3.85%, 기형정자수는 6.57$\pm$0.43~5.54$\pm$0.52%로 나타났다. 2. 분획별 채취 전정액중 제 1 분획에서는 정액량이 0.92$\pm$0.7$m\ell$, 정자농도는 4.57$\pm$0.78$\times$$10^{6}$cells/$m\ell$, 정자활력은 10.72$\pm$3,21%, 기형정자수는 5.50$\pm$0.70%로 나타났으며, 제 2분획에서는 정액량이 2.14$\pm$0.19$m\ell$, 정자농도는 2.01$\pm$0.12$\times$$10^{6}$cells/$m\ell$, 정자활력은 95.44$\pm$4.21%, 기형정자수는 4.31$\pm$0.53%로 나타났다. 또한, 제3 분획에서는 정액량이 2.66$\pm$0.23$m\ell$, 정자농도는 2.35$\pm$0.21$\times$$10^{6}$cells/$m\ell$, 정자활력은 90.71$\pm$2.63%, 기형정자수는 6.33$\pm$0.91%로 나타났다. 3. 원정액과 정장제거 정액을 4$^{\circ}C$ 와 2$0^{\circ}C$ 및 37$^{\circ}C$ 에서 각각 보존했을 때 보존시간별 정자의 활력은 2$0^{\circ}C$ 의 경우 1, 6, 13, 24, 30 및 40 시간에서 각각 98.51%와 98.32%, 86.32%와 92.15%, 83.71% 와 89.20%, 74.29% 와 82.08%, 52.98% 와 72.07%, 15.45% 와 60.02%, 2.41% 와 37.19% 의 정자활력을 나타내어 4$^{\circ}C$와 37$^{\circ}C$에 비해 높은 정자운동성을 나타냈다. 4. 제 2 분획 정액과 정장제거 정액을 각각 제 1차 및 제 2차 희석액으로 희석 평형 시킨 후 동결 융해했을 때 정자의 생존율은 각각 33.3$\pm$8.7, 54.7$\pm$9.5%로서 대조군의 15.4$\pm$5.2% 에 비해 높게 나타났다.

• 대기
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• 제33권4호
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• pp.367-385
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• 2023

The variabilities of precipitation and particulate matters (i.e., PM₁₀ and PM_2.5) and the scavenging efficiency of PMs by precipitation were quantified using long-term measurements in Seoul, Korea. The 21 years (2001~2021) measurements of precipitation and PM₁₀ mass concentrations, and the 7 years (2015~2021) of PM_2.5 mass concentrations were used. Statistical analysis was performed for each period (i.e., year, season, and month) to identify the long-term variabilities of PMs and precipitation. PM₁₀ and PM_2.5 decreased annually and the decreasing rate of PM₁₀ was greater than PM_2.5. The precipitation intensity did not show notable variation, whereas the annual precipitation amount showed a decreasing trend. The summer precipitation amount contributed 61.10% to the annual precipitation amount. The scavenging efficiency by precipitation was analyzed based on precipitation events separated by 2-hour time intervals between hourly precipitation data for 7 years. The scavenging efficiencies of PM₁₀ and PM_2.5 were quantified as a function of precipitation characteristics (i.e., precipitation intensity, amount, and duration). The calculated average scavenging efficiency of PM₁₀ (PM_2.5) was 39.59% (35.51%). PM₁₀ and PM_2.5 were not always simultaneously scavenged due to precipitation events. Precipitation events that simultaneously scavenged PM₁₀ and PM_2.5 contributed 42.24% of all events, with average scavenging efficiency of 42.93% and 43.39%. The precipitation characteristics (i.e., precipitation intensity, precipitation amount, and precipitation duration) quantified in these events were 2.42 mm hr^-1, 15.44 mm, and 5.51 hours. This result corresponds to 145% (349%; 224%) of precipitation intensity (amount; duration) for the precipitation events that do not simultaneously scavenge PM₁₀ and PM_2.5.