• Journal of Environmental Health Sciences
• /
• v.40 no.3
• /
• pp.215-224
• /
• 2014

Objective: This study was carried out in order to determine the depositional characteristics of pine needles, pine bark, and soil used as a passive air sampler (PAS) for atmospheric polybrominated diphenyl ethers (PBDEs). Methods: All three media were sampled from the same site. The PBDE concentrations were analyzed by HRGC/HRMS, and the lipid contents were measured using the gravimetric method by n-hexane extraction. Results: The total PBDE concentration was the highest in soil (22,274.57 pg/g dry), followed by pine bark (20,266.39 pg/g dry), and then pine needles (7,380.22 pg/g dry). Pine needles contained the highest lipid contents (21.31 mg/g dry), whereas soil (10.01 mg/g dry), and pine bark (4.85 mg/g dry) contained less. There were poor correlations between lipid content and total PBDE concentrations in the media ($R^2$=0.8216, p=0.2814). Congeners BDE 47, 99, 183, 196, 197, 206, 207 and 209 showed peak concentrations. Among these, BDE 206, 207, and 209 are highly brominated PBDEs that exist as particulates in ambient air. They accounted for 81.2% [69.2 (pine needles) - 89.0% (tree bark)] of the concentration and therefore are noted as the main congener of the total PBDEs. Conclusions: It can therefore be concluded that for reducing error by improper sampling, the same species of media should be recommended for use as a PAS for atmospheric PBDEs due to the differences in depositional characteristics.

• Journal of Pharmaceutical Investigation
• /
• v.21 no.3
• /
• pp.155-160
• /
• 1991

Particulate is the foreign insoluble material in injectable solution inadvertently present in a given product. Considerable efforts have been made to avoid or minimize particulate contamination by pharmaceutical manufacturers during the production of parenteral products. Particulate contamination of the parenteral products can occur mainly during the opening (cutting) the container immediately before clinical use. In this study, particulate contamination generated during the opening process of ampoules (conventional type, 1-point and color-break ampoules) was compared with that of a prefilled injectable container (prefilled syringe). The particles were examined under a microscope after filtration of the total fluids in the containers. Particles having wide range of size distribution were found from all the ampoules tested. The contamination from the I-point ampoule and colorbreak ampoule was much less than from the conventional ampoule. Glass particles generated by cutting the glass-made ampoules seemed a principal source of the particulate contamination. The glass-partiaulte contamination could be improved substantially by replacing the ampoule containers with the prefilled syringe. Prefilled syringe, which can be used without any cutting process. did not generate particulates during the use. Therefore, it was concluded that prefilled syringe is most preferable container for the small volume parenteral (SVP) fluids in terms of particulate contamination.

• IE interfaces
• /
• v.10 no.1
• /
• pp.237-248
• /
• 1997

The purpose of this study is to make an economic analysis of power plant utilities by examining electricity generating costs with environmental consideration. Economic growth has caused pollutant emission, and subsequent environmental pollution has been identified as a very real limit to sustainable development. Considering the enormous role of electricity in the national economy, it is thus very important to study the effect of environmental regulations on the electricity sector. Because power utilities need large investments during construction, operation and maintenance, and also require much construction lead time. Economic analysis is the very important process in the electric system expansion planning. In this study, the levelized generation cost method is used in comparing economic analysis of power plant utilities. Among the pollutants discharged of the electricity sector, this study principally deals with the control activities related only to $CO_2$, and $NO_2$, since the control cost of $SO_2$, and TSP (Total Suspended Particulates) is already included in the construction cost of utilities. The cost of electricity generation in a coal-fired power plant is compared with one in an LNG combined cycle power plant. Moreover this study surveys the sensitivity of fuel price, interest rate and carbon tax. In each case, this sensitivity can help to decide which utility is economically justified in the circumstance of environmental regulations.

• International Journal of Automotive Technology
• /
• v.7 no.5
• /
• pp.527-534
• /
• 2006

Modern passenger cars with diesel engines are equipped with DOC(diesel oxidation catalyst) for the purpose of reducing HC and CO in the exhaust stream. Cold start exhaust emissions pose troubles here as on gasoline engine vehicles. As a result, some of the diesel passenger cars roll off todays the assembly lines with WCC(warm-up catalytic converter). Oxidation characteristics of the particulates in WCC is analyzed in this study by EEPS(engine exhaust particulate size spectrometer). The maximum number of PM is found to come out of WCC in sizes near 10nm when an HSDI diesel engine is operated under the conditions of high speed and medium to heavy load. When the temperature of the WCC exceeds $300^{\circ}C$, the number of PM smaller than 30 nm in diameter sharply increases upon passing through the WCC. Total mass of emitted PM gets reduced downstream of the WCC under low speed and light load conditions due to adsorption of PM onto the catalyst. Under conditions of high speed and medium to heavy load, the relatively large PM shrink or break into fine particles during oxidation process within the WCC, which results in more mass fraction of fine particles downstream of the WCC.

• Environmental Engineering Research
• /
• v.22 no.1
• /
• pp.75-86
• /
• 2017

The aerosol content dynamics in a virtual system were investigated. The outcome was extended to monitor the mean concentration diffusion of aerosols in a predefined macro and micro scale. The data set used were wind data set from the automatic weather station; satellite data set from Total Ozone Mapping Spectrometer aerosol index and multi-angle imaging spectroradiometer; ground data set from Aerosol robotic network. The maximum speed of the macro scale (West Africa) was less than 4.4 m/s. This low speed enables the pollutants to acquire maximum range of about 15 km. The heterogeneous nature of aerosols layer in the West African atmosphere creates strange transport pattern caused by multiple refractivity. It is believed that the multiple refractive concepts inhibit aerosol optical depth data retrieval. It was also discovered that the build-up of the purported strange transport pattern with time has enormous potential to influence higher degrees of climatic change in the long term. Even when the African Easterly Jet drives the aerosols layer at about 10 m/s, the interacting layers of aerosols are compelled to mitigate its speed to about 4.2 m/s (macro scale level) and boost its speed to 30 m/s on the micro scale level. Mean concentration diffusion of aerosols was higher in the micro scale than the macro scale level. The minimum aerosol content dynamics for non-decaying, logarithmic decay and exponential decay particulates dispersion is given as 4, 1.4 and 0 respectively.

• Environmental Engineering Research
• /
• v.12 no.3
• /
• pp.118-127
• /
• 2007

Between June and November 2002, the atmospheric concentrations and dry deposition fluxes of polycyclic aromatic hydrocarbons (PAHs) in Chonju were measured four times each over five days. The total concentration of PAHs in ambient air was $84\;ng/m^3$, with about 90% existing in the vapor phase. Plots of log ($K_p$) vs. log (${P_L}^0$) indicated that PAHs partitioning was not in equilibrium and the particulate characteristics did not change with seasonal variations. The PAHs fluxes to a water surface sampler (WSS) and a dry deposition plate (DDP) were about 14.15 and $1.92\;{\mu}g/m^2/d$, respectively. The flux of the gaseous phase, acquired by subtracting the DDP from the WSS results, was about $12.23\;{\mu}g/m^2/d$. A considerable correlation was shown between the atmospheric concentrations and deposition fluxes in the gaseous phase, but not in the particulate phase, as the fluxes of the particulate phase were dependent on the physical velocity differences of the particulates based on the particle diameter.

• Advances in environmental research
• /
• v.6 no.2
• /
• pp.139-146
• /
• 2017

The purpose of this study was to determine the present air pollutant concentrations and predicted levels for next 30 years in urban environment of Karachi city. For that, a total of fifty measurements were made for each twenty selected locations of the city. The locations were selected on the basis of land use pattern such as residential, commercial, industrial settlements, open areas, congested traffic and low traffic areas for investigation of air pollutants variability and intensity. The measurements were taken continuously for six months period using PM Meter, Model AEROCET 531 and Ambient Air Quality Meter, Model AAQ 7545. The concentration of air pollutants were found higher at Al Asif Square and Maripur Road due to higher intensity of traffic and at Korangi Crossing because of industrial areas. The level of pollutants was lower at Sea View owing to lower traffic congestion and transportation of pollutants by sea breezes.

• Proceedings of the Membrane Society of Korea Conference
• /
• 1996.06a
• /
• pp.121-147
• /
• 1996

Since 1980, the water quality of ultra-pure water has been rapidly improved, and presently ultra-pore water producing equipment for 64Mbit is in operation. Table 1 shows the degree of integration of DRM and required water quality exlmple. The requirements of the ultra-pure water for 64Mbit are resistivity: 18.2 MQ/cm or higher, number of particulates: 1 pc/ml or less (0.05 $\mu$m or larger). bacteria count: 0.1 pc/l or less. TOC (Total Organic Carbon, index of organic snbstance) : 1ppb or less, dissolved oxygen: 5ppb or less, silica: 0.5ppb or less, heavy metal ions: 5ppb or less. The effect of metals on the silicon wafer has been well known, and recently it has been reported that the existence of organic substance in ultra-pure water is closely related to the device defect, drawing attention. It is reported that if organic substance sticks to the natural oxidation film, the oxide film remaims on the organic substance attachment in the hydrofluoric acid treatment (removal of natural oxidation film). The organic substance forms film on the silicon wafer, and harmful elements such as metals and N.P.S., components contained in the organic substance and the bad effect due to the generatinn of silicon carbide cannot be forgotten. In order to remove various impurities in raw water, many technological develoments (membrane, ion exchange, TOC removal, piping material, microanalysis, etc.) have been made with ultra-pure water producing equipment and put to practical use. In this paper, technologies put to practical use in recent ultra-pure vater producing equimeut are introduced.

• Journal of Environmental Health Sciences
• /
• v.19 no.1
• /
• pp.37-43
• /
• 1993

The airborne concentrations of Sulfur Dioxide and Total Suspended Particulates were investigated in 4 subway lines in Seoul at early summer, 1990 and early summer, 1991. The results of the study were as follows: 1. The airborne concentrations of SO$_2$ and TSP were 0.022 ppm, 445.7 $\mu$g/m$^3$ respectively. And percents of over annual air quality standard of WHO was that SO$_2$ and TSP were 41.7%, 100% respectively. 2. Airborne SO$_2$ concentrations by subway lines were that line 1 was 0.025 ppm, line 2 was 0.023 ppm, line 3 was 0.020 ppm, and line 4 was 0.017 ppm. And TSP concentrations by subway lines were that line 2 was 533.8 $\mu$g/m$^3$, line 1 was 516.5 $\mu$g/m$^3$, line 4 was 371.6 $\mu$g/m$^3$, and line 3 was 369.3 $\mu$g/m$^3$ 3. Annual variation of concentration of TSP was not significant statistically (t=0.327), and that of SO$_2$, in 1990 was slightly higher than that in 1991 (t=1.433, p<0.1). 4. Coefficients of correlation between TSP and SO$_2$ by years were that early summer, 1990 was r=0.277 (p>0.1), and early summer, 1991 was r=0.32 (p>0.1).

• Journal of Environmental Health Sciences
• /
• v.37 no.3
• /
• pp.209-217
• /
• 2011

Objectives: In this study, the size distribution of airborne particulates ($PM_{10}$) was measured by using Cascade Impactors. The purpose of this study was to assess the size distribution of metal and ionic materials of $PM_{10}$. Methods: Samples were collected in the Kunsan industrial complex from April 2006 to January 2007. Results: The mass fraction of $PM_{10}$ had a bimodal distribution between 2.1-3.1 ${\mu}M$, and the average mass fraction of particles less than 2.1-3.1 ${\mu}M$ was 47%. Average concentrations of PM10 were 68.05 ${\mu}g/m^3$ and seasonal concentration 95.44 ${\mu}g/m^3$ for spring, 49.03 ${\mu}g/m^3$ for summer, 81.99 ${\mu}g/m^3$ for fall, 52.66 ${\mu}g/m^3$ for winter, respectively. Conclusions: Seasonal variations of $PM_{10}$ were significant for showing peak values in spring. The average concentrations of Cd, Cr, Pb, and Fe were 1.54, 4.51, 14.11, and 254.3 $ng/m^3$, respectively. The ratios of fine particles to total mass were 0.47 for $PM_{10}$, 0.45 for Cr, and 0.16 for Fe, 0.91 for Cd and 0.49 for Pb, respectively.