• 한국대기환경학회지
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• 제10권2호
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• pp.130-136
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• 1994

Concentration of volatile particulate nitrate(NH$_4$NO$_3$) in TSP in ambient air was determined from Feb. to Oct 1993. Sampling was carried out using a two-stage Andersen air sampler at the top of a five-story building located at Kon- Kuk University in Seoul Concentration of NH$_4$NO$_3$ in TSP was measured by Pyrolysis of sample filters at 16$0^{\circ}C$ for 1hr. Concentration of NH$_4$NO$_3$ was higher in winter time compared with that in summer time. Also, concentration of NH$_4$NO$_3$ was higher in fine particles compared with that in coarse particle. The range of NH$_4$NO$_3$concentration was between 2.99 and 9.86 $\mu\textrm{g}$/㎥. Weight fraction of NH$_4$NO$_3$ in total particulate nitrate was 31.1~59.5%, and weight fraction of NH$_4$NO$_3$ in YSP was 2.1~11.2%.

• 한국대기환경학회지
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• 제2권1호
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• pp.73-79
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• 1986

This study is carried out to determine the concentration of the ozone and the factors affecting the variation of ozone concentration in the ambient air in Seoul. The one-hour average concentration of ozone $(O_3)$, sulfur dioxide $(SO_2)$, nitrogen oxides (NO and $NO_2$), suspended particulate (TSP), carbon monoxide (CO) and non-methane hydrocarbon (NMHC) at 5 sites in Seoul measured from September to October in 1983 and 1984 were analysed statistically along with meteorological data for the same period. The results were as follows; 1. The average concentrations of ozone at 5 sites during the period ranged from 3.3 to 9.1 ppb, they were below 20 ppb of the ambient air quality standard of Korea. 2. The maximum hourly concentration of ozone occurred between 2 and 3 p.m. in a day and concentration at night were very low but higher concentrations were observed at around 4 a.m. 3. The concentration ratio between NO and $NO_2$ in Seoul was relatively lower than that for the cities of foreign countries reported so far. 4. The ozone concentration has negative correlationships with the concentration of other primary pollutants$(SO_2, NO, NO_2, CO and NMHC)$ in simple regression analyses. 5. The ozone concentration was positively correlated to wind speed, temperature and insolation intensity but negatively correlated to relative humidity. 6. Stepwise multiple regression analysis of the ozone concentration to the pollutants and meteorological factors indicate that insolation intensity and $[NO_2]/[NO]$ were the primary influencing factors. 7. The three factors of insolation intensity, $[NO_2]/[NO] and NO_2$ concentration had a significant combined effect on the ozone concentration $(r^2 = 0.47-0.57)$.

• 한국환경과학회지
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• 제15권3호
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• pp.203-209
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• 2006

In predicting oxidants concentration, the most important fact is to select a suitable photochemical reaction mechanism. Sensitivity analysis of $O_3$ and other important photochemical oxidants concentrations was conducted by using CBM-IV model. The predicted oxidants concentration was considerably related with the initial concentration of formaldehyde, $[NO_2]/[NO],\;NO_x$, RH and RCHO. As the initial concentration of formaldehyde increased, concentration of $NO_2$ increased. $O_3$ concentration was proportional to the $[NO_2]/[NO]$ ratio. When the initial concentrations of RH and RCHO were high, photochemical reaction was more reactive, including more rapid conversion of NO to $NO_2$ and increased oxidants. Also, the sensitivities of ozone formation to rate constants, $K_l,\;K_2\;and\;K_3$ in the $NO_2$ photolysis were studied.

• 한국환경보건학회지
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• 제26권4호
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• pp.141-147
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• 2000

Due to a rapid in automobiles since the 1980’s, the concentration of NO, and HC has also increased along with cases of VOCs. These air pollutants have created $O_3$ concentration, which cause a harmful effect to the human health. This issue has become a subject of great public interest. For this paper, to compare the concentration of $O_3$, NO, N $O_2$ between the rural and urban area in the winter, the concentrations of each have been measuredevery hour during Jan.~Feb. 2000, 1998, respectively. To calculate the Photochemical Steady State, $\Phi$= $J_{N O_2}$[N $O_2$]/ $k_1$[NO][ $O_3$], temperature and $J_{ N O_2}$ has been determined. The NO concentration in the rural are showed at below 10 ppb while the NO concentration in the urban area showed maximum value of 90~120 ppb. But the $O_3$ concentration in both areas showed less than 30 ppb. The reason is that the N $O_2$ photodissiciation rate is low due to the temperature being below 2$^{\circ}C$ and less than 60 degrees in the solar zenith angle during the winter time, which makes the $O_3$ concentration in both areas, similar in the concentration level. N $O_2$ photodissociation rate in both ares showed maximum value of 3.0mW/$\textrm{cm}^2$. Values of $\Phi$ determined from the rural area was consistently the unity, approaching 1. But values of $\Phi$ determined from the urban was roughly higher than unity, approaching above 1or 2 for clear sky-high sun(10:00~16:00).

• 한국환경과학회지
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• 제27권7호
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• pp.587-595
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• 2018

This research investigated the characteristics of NO and $NO_2$ concentration at roadside (Choryangdong) and residential (Sujeongdong) locations in Busan. The NO concentration at roadside and residential were 34.7 and 8.0 ppb, respectively, and $NO_2$ at roadside and residential were 31.6 and $18.0ppb\;{\mu}g/m^3$, respectively. The NO concentration was the highest in winter at roadside at 37.1 ppb, followed by 35.0 ppb and 34.0 ppb in summer and fall, respectively. $NO_2$ concentration was the highest in spring at roadside at 39.6 ppb, followed by 30.4 ppb and 28.3 ppb in fall and winter, respectively. Number of exceedances per year of 1 hr limit value (0.10 ppm) for $NO_2$ at roadside and residential were 3,585 and 3 hours, respectively. Number of exceedances per year of 24 hr limit value (0.06 ppm) for $NO_2$ at roadside and residential were 32 and 1 days, respectively. Number of exceedances per year of 1 hr limit value (0.1 ppm) for $O_3$ at roadside and residential were 1 and 14 days, respectively. These results indicated that understanding the relationship between roadside and residential could provide insight into establishing a strategy to control urban air quality.

• 한국표면공학회지
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• 제52권4호
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• pp.233-238
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• 2019

The formation behavior of zinc phosphate conversion coating (ZPCC) on SCM430 alloy was investigated in 25 vol.% of 1M ZnO + 170 ml/L solution containing various $Fe(NO_3)_2$ concentrations, using open-circuit potential(OCP), electrochemical impedance spectroscopy(EIS), cyclic polarization(CP) curve and tape peel test. OCP of SCM430 alloy and corrosion current density increased with increasing $Fe(NO_3)_3$ concentration. Resistance of films formed on SCM430 alloy by chemical conversion treatment decreased with increasing $Fe(NO_3)_3$ concentration. Color and adhesion of chemical conversion coatings became darker and worse, respectively, with increasing $Fe(NO_3)_3$ concentration. It is concluded that addition of $Fe(NO_3)_3$ into a zinc phosphating bath leads to faster reaction to form porous surface coatings with poor adhesion and corrosion resistance.

• 한국대기환경학회지
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• 제21권1호
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• pp.15-26
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• 2005

An experimental investigation of the gas-phase photooxidation of toluene-NO$_{x}$-air mixtures at sub-ppm concentrations has been carried out in a 6.9 m3, indoor smog chamber irradiated by blacklights. Measured parameters in the toluene-NO$_{x}$ experiments included $O_3$, NO, NO$_2$, NO$_{x}$, CO, SO$_2$ toluene, and air temperature. The initial toluene concentration ranged from 225 ppb to 991 ppb and the initial concentration ratio of toluene/NO$_{x}$ in ppbC/ppb was in the range of 5～20. It was found that the variation of gaseous species with irradiation time caused by the photooxidation of toluene-NO$_{x}$-air mixtures depended on the initial toluene concentration for similar concentration ratio of toluene/NO$_{x}$. The dependency of initial toluene concentration on the photooxidation of toluene-NO$_{x}$-air mixtures for toluene/NO$_{x}$=5～6 seemed to be opposite to that for toluene/NO$_{x}$=10～11. The arriving time at maximum ozone concentration depended on both initial toluene concentration and initial concentration ratio of toluene/NO$_{x}$. However, the maximum concentration of ozone formed by photooxidation depended only on the initial toluene concentration.luene concentration.

• 한국수산과학회지
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• 제30권5호
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• pp.782-793
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• 1997

식물 플랑크톤의 인위적인 용승조건 하에서 생리적 적응 (shift-up)을 알아보기 위하여, 안정동위원소인 $^{15}N-KNO_3$를 이용하여 실험실에서 Dunaliella tertiolecta의 질산염 흡수 능력을 측정하였다. 그 결과 예상과는 달리 최대 질소비 질산염 흡수 속도 $(V_{NO3})$와 초기 질산염 농도 사이에는 유의성 있는 상관관계가 나타나지 않았다. 그러나 최대 질산염 운반 속도 $(\rho_{NO3})$와 $25\;{\mu}M$ 이하의 초기 질산염 농도 사이에는 강한 상관성이 나타났으며, 이는 배양 세포의 생리적인 상태에 의한 영향에도 기인한다. $\rho_{NO3}$의 증가는 주로 입자성 유기 질소 농도의 증가와 함께 부분적으로는 $V_{NO3}$의 증가에 기인한다. 식물 플랑크톤 개체군이 심하게 shift-down되었을 경우 질산염 흡수의 생리적 적응은 높은 초기 질산염 농도에서 주목할 만큼 저해되었다. 최대 $V_{NO3}$ 또는 $\rho_{NO3}$이 나타나는 시기는 초기 질산염 농도와 관련이 있다. 높은 초기 질산염 농도에서는 $V_{NO3}$와 $\rho_{NO3}$의 최대치가 낮은 초기 질산염 농도에서보다 $1\~2$일 정도 늦게 나타났다. 이는 Zimmerman et al. (1987)의 shift-up 모델에서의 예측과 상반되는 결과이다. Shift-up 과정은 명백히 내부적인 시간순서와 초기 질산염 농도에 의하여 조절되지만, $V_{NO3}$의 크기는 질산염 농도의 변화에 거의 영향을 받지 알았다.

• 한국환경과학회지
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• 제23권5호
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• pp.861-871
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• 2014

This study analyzes the characteristics of ozone weekend effect(OWE) in Busan. $O_3$ concentration on Sunday was over 10% higher than that on weekdays in all areas except for Kwangbokdong, Taejongdae, and Joadong. Such a difference was higher in the industrial area than in the residential area. $O_3$ generation was facilitated by the decrease in $NO_X$ emission on Sunday in VOC-limited regime where the VOC/$NO_X$ ratio is low. Low NO concentration in the Sunday morning decreased inhibition of $O_3$. NO-$O_3$ crossover time on Sunday was shorter than that on weekdays which in turn extended the accumulated duration of $O_3$. Future studies can include whether the entire Busan is VOCS-limited or the coastal area is VOCS-limited while the inland area is $NO_X$-limited.

• 한국환경과학회지
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• 제14권11호
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• pp.1035-1047
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• 2005

By using hourly $NO_2$ concentration data$(1998\~2000)$ at the Busan Metropolitan City air qualify monitoring sites, characteristics of daily mean value of $NO_2$ concentration was discussed in space and time. The correlation between $NO_2$ concentration and other relating air pollutants was analyzed by using SAS program and meteorological parameters as well. After choosing representative 4 areas, this study used hourly concentration data$(1998\~2000)$ from air quality monitoring sites on $NO_2,\;NO,\;O_3,\;CO,\;SO_2\;and\;PM_{10}$. Typical metropolitan characteristics of two peaks in a day was shown in the variation of $NO_2$ concentration of Busan city.