• Carbon letters
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• v.15 no.4
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• pp.295-298
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• 2014

In this work, nanoporous carbons (NPCs) were prepared by the self-assembly of polymeric carbon precursors and block copolymer template in the presence of tetraethyl orthosilicate and colloidal silica. The NPCs' pore structures and total pore volumes were analyzed by reference to $N_2$/77 K adsorption isotherms. The porosity and elemental mercury adsorption of NPCs were increased by activation with carbon dioxide. It could be resulted that elemental mercury adsorption ability of NPCs depended on their specific surface area and micropore fraction.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.31 no.1
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• pp.13-21
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• 2021

Objectives: The purpose of this study was to evaluate the exposures of cashiers who work at expressway tollbooths. Methods: We measured temperature(temp.), relative humidity(RH), and contaminants with direct reading instruments at ten expressway toll gate in September 2015. Elemental carbon was collected on the quartz filters and analyzed with an OCEC analyzer. Results: The average levels for temp., RH, carbon monoxide, carbon dioxide, dust(PM10), and black carbon were respectively 24.6~27.8℃, 32.3~65.3%, 0.5~1.2 ppm, 456~559 ppm, 12~111 ㎍/㎥, and 3.1~10.1 ㎍/㎥ at each tollbooth. The concentrations of elemental carbon within the tollbooth(1.8~7.2 ㎍/㎥) were lower than outdoors(2.5~10.0 ㎍/㎥), but exhibited a high correlation(r2=0.855). The exposure levels for carbon monoxide, black carbon, and elemental carbon in the tollbooths were significantly higher than the offices. The concentrations of black carbon and elemental carbon showed a high correlation(r2=0.756). Conclusions: The levels of contaminants were below the occupational exposure limits in the expressway tollbooth. There were ventilation and air conditioning systems in the booths, but it is necessary to maintain and use the systems properly.

• Journal of Conservation Science
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• v.20
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• pp.55-65
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• 2007

Black surface layers collected from stone pagodas were analyzed to study the effects of carbon compounds on the blackening of stone surface layer. The total amounts of carbon was measured through elemental analyser. Organic and elemental carbon were measured by combustion ihrornatographic $CO_2$ determination after elimination of carbonates carbon with acid treatment. The elemental carbon concentration in the black surface layer measured 0.52wt.%. This value is not sufficient to explain the complete blackening of stone surface. To trace the origin of carbon in black surface layer on the stone pagoda, aerosol samples for PM 10 were collected at the near sites of the pagoda. The major components of them were soluble ions(42.8wt.%), carbon(38.4 wt.%) and crustal matter(16wt.%). From the high content(13wt.%) of elemental carbon in aerosol ran be deduced that it may be a prime origin for the elemental carbon in the black surface layer on the stone pagoda. The crustal matter in aerosol can be also a origin of silicate mineral in black surface layer and plays a important role in the darkening of black surface layer.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2006.10a
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• pp.173-174
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• 2006

• Journal of Environmental Health Sciences
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• v.16 no.2
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• pp.31-39
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• 1990

An analytical method for particulate carbon and other elements by using elemental analyzer was investigated. Carbon, hydrogen, and nitrogen was determined as CO$_{2}$, H$_{2}$, and N$_{2}$, respectively. Organic was determined after scparation from elemental carbon(Cae) by volatilization and thermal decomposition in a heated helium flow. With organic materials examined in this reprot, more than 90% of carbon was detected as above 600$^{\circ}$C. But it is considered that a few percents of some compounds were charred above 550$^{\circ}$C. A small amount of Cae was oxidized in the inert atmosphere above 850$^{\circ}$C, but the reason was not explained clearly. Based on the thermal chracteristics of Cao it was found that the optimum temperature of heating in the helium flow of an elemental analyzer for Cao analysis is 630$^{\circ}$C. Carbon in a sample after removing Cao was assumed as Cae and the gramatom ratio of hydrogen to carbon in the sample was 0.4 and less. Rescovery of nitrogen derived from some ammonium salts and nitrates was 100% by two-step measurement with elemental analyzer. By the analytical method investigated in this report, carbon and other elements in suspended particulates(S.P) collected at an urban area in Seoul were measured. There was a good correlation between total nitrogen in SP measured by elemental analyzer and nitrogen estimated form ammonium ions and nitrate ions in SP. The nitrogen from these ions accounts for 80% of the total nitrogen. It is further suggested that the residue(20%) of the total nitrogen is attributed to the other nitrogeneous compounds.

• Journal of Korean Society for Atmospheric Environment
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• v.16 no.2
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• pp.103-112
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• 2000

Elemental carbon(EC) and organic carbon(OC) in fine particles (PM2.5) were collected from October 1995 through August 1996 in the Chongju area. The annual mean concentrations of EC and OC were 4.44 and 4.99 $\mu\textrm{g}$/m3 respectively. EC showed seasonal variation (p<0.01) The magnitude of the seasonal mean EC concen-tration progresses in the following manner : fall>winter>spring>summer. However OC was not statistically seasonal difference(p=0.20) The annual average OC/EC ratio was 1.12 suggesting that organic carbon measured may by emitted directly in particulate form(primary aerosol) The contribution of EC to PM2.5 mass follows a general pattern in which fall(14.6%) > winter (9.8%) >spring(7.8%) =summer(7.8%) and the contribution of OC to the PM2.5 mass varies in order fall(13.8%) >winter(11.3%) >spring(10.5%) >summer (9.4%) Total carbona-ceous particles(EC and OC) accounted for 17-28% of the PM2.5 mass.

• Journal of Korean Society for Atmospheric Environment
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• v.13 no.3
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• pp.179-191
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• 1997

The concentrations of organic and elemental carbon were determined using fine particle samples collected from Kosan, Cheju Island during the summer seasons of 1994 and 1995. The daily mean concentrations of organic and elemental carbon for each measurement period were 3.74 and 0.27 $\mu\textrm{g}$/㎥ in 1994, while those of 1995 were 2.36 and 0.10 $\mu\textrm{g}$/㎥, respectively The concentrations of organic carbon were higher than those commonly observed from clean areas around the world, but those of elemental carbon were lower than, or comparable to, other clean areas in the world. The resulting ratios of total carbon to elemental carbon at this site were thus higher than those seen from other metropolitan and non-polluted regions abroad. In addition according to our analysis, the 1994 measurement period can be classified into two periods: enhanced (July 20 and August 1) and reduced levels (August 2 and 9) of the carbonaceous species. The observed difference between two periods may be in part accounted for by the air trajectories representing each period. During the former period, the air masses from the Asian continent and Japan were dominant, while the air masses from the North Pacific Ocean came during the latter period. OC/EC ratios at the site were calculated to predict the possible formation of secondary organic aerosol . Based on our observations, we suggest that the formation of secondary organic aerosol might be an important pathway to the production of organic carbons.

• Bulletin of the Korean Chemical Society
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• v.32 no.4
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• pp.1321-1326
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• 2011

In this work, the effects of different surface functional groups on the elemental mercury adsorption of porous carbons modified by chemical treatments were investigated. The surface properties of the treated carbons were observed by Boehm's titration and X-ray photoelectron spectroscopy (XPS). It was found that the textural properties, including specific surface area and pore structures, slightly decreased after the treatments, while the oxygen content of the ACs was predominantly enhanced. Elemental mercury adsorption behaviors of the acidtreated ACs were found to be four or three times better than those of non-treated ACs or base-treated ACs, respectively. This result indicates that the different compositions of surface functional groups can lead to the high elemental mercury adsorption capacity of the ACs. In case of the acid-treated ACs, the $R_{C=O}/R_{C-O}$ and $R_{COOH}/R_{C-O}$ showed higher values than those of other samples, indicating that there is a considerable relationship between mercury adsorption and surface functional groups on the ACs.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.E2
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• pp.77-85
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• 2004

In order to investigate the scavenging property of airborne carbonaceous particles by precipitations, rainwater, snow sample, and total suspended particulate matter (TSP) were collected at a heavily industrialized urban site. Elemental carbon (EC) contents of both rainwater and snow water were deter-mined using elemental analysis system. EC concentrations in rain samples varied from 33.6 to 166.6 $\mu\textrm{g}$ L$^{-1}$ with an average 47.2 $\mu\textrm{g}$ L$^{-1}$ . On the other hand, those of snow samples in three times snow events were ranged from 122.4 to 293.3 $\mu\textrm{g}$ L$^{-1}$ . As might be expected, EC showed the significantly high scavenging rate at the initial rainfall. The average total carbon (TC) scavenging rate by washout mechanisms was 57.6% for five rainfall events. The scavenging rate of EC gradually increased in proportion to the increasing rainfall intensity and rainfall amount.

• Journal of Environmental Health Sciences
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• v.23 no.4
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• pp.91-96
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• 1997

In order to investigate the behavior of particulate carbon and benzo(a)pyrene(B(a)P) in the ambient air, suspended particle matters were collected from April, 1990 to February, 1992, and total carbon(TC), organic carbon(OC), elemental carbon(EC) and B(a)P were measured by an elemental analyzer and a HPLC. The results were as follows the average concentration of TC was 38.6 $\mug/m^3$ and its concentration was higher in winter(45.4 $\mug/m^3$) and fa11(44.3 $\mug/m^3$) than in summer(36.8 $\mug/m^3$) and spring(28.9 $\mug/m^3$). The monthly concentration trends both of EC and OC was similar, but seasonal variation of EC concentrations was larger than that of OC. The average concentration of B (a)P was 2.2 ng/m$^3$, and was higher in winter(4.1 ng/m$^3$) and fall(3.2 ng/m$^3$) than in spring(1.2 ng/m$^3$) and summer(0.6 ng/m$^3$). The seasonal behavior of carbon and B(a)P was to similar except for summer. The correlation coefficient(r) between EC and B(a)P was 0.71, and the correlation coefficient(r) between OC and B(a)P was 0.66.