• 한국대기환경학회지
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• 제18권4호
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• pp.297-303
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• 2002

Fine particles (d$_{p}$ < 2.5 $\mu$m) were measured using an annular denuder system (ADS) in Chongju. The data set was collected on fifty-eight different days with a 24-hr sampling period from October 27, 1995 through August 25, 1996. Particulate nitrate in the ADS was also measured on teflon and nylon filters in series behind denuders to collect HNO$_3$, HNO$_2$, SO$_2$and NH$_3$. From this study. the mean concentration of particulate nitrate of PM$_{2.5}$ in the ADS were seen with the following order: winter (5.05) ＞fall (4.36) ＞spring (3.92) > summer (1.10 $\mu\textrm{g}$/㎥). Nitrate losses, which calculated from the ratio of nylon filter nitrate to the sum of teflon and nylon filter nitrates, varied in the following manner summer (72.2%) > spring (42.6%) > fall (23.5%)> winter (0.4%). Especially, gaseous nitric acid was dominant at temperature higher than 8$^{\circ}C$ while particulate nitrate was major species in total nitrate below that temperature. This indicates the particulate nitrate loss is strongly correlated rather with ambient temperature.e.e.

• 한국대기환경학회지
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• 제8권1호
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• pp.68-73
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• 1992

A study on the formation of particulate nitrate$(NO_3^-)$ and gaseous nitrate$(HNO_3)$ in the atmosphere was carried out in Seoul from Oct 8 to 11 1991. To collect $NO_3^-$ and $HNO_3$ in the ambient air, dual filter pack sampler (47mm$\phi$) was used. In the dual filter pack sampler, the first filter was Teflon filter (poresize 1$\mum$) for collection of $NO_3^-$ and the second filter was Nylon filter (poresize 0.45 $\mum$) for $HNO_3$. Particulate nitrate$(NO_3^-)$ and Sulfate ions were analysed by Ion chromatography. $HNO_3$ concentration was higher in the day time $(9.93\mug/m^3)$ than the night time$(3.50\mug/m^3)$, and Particulate nitrate$(NO_3^-)$ concentration was higher in the night time and early morning$(6.21\mug/m^3)$ than the day time$(4.31\mug/m^3)$. The conversion rate of $NO_x$ to total nitrate$(NO_3^-, HNO_3)$ was 7.57%/hr in the day time and 4.79%/hr in the night time, and total average conversion rate was 5.60%/hr.

• 한국대기환경학회지
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• 제20권6호
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• pp.729-738
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• 2004

Seasonal variation of major inorganic ions in the greater Seoul area was estimated using a photochemical box model and a gas/aerosol equilibrium model with emphasis on semi -volatile nitrate. Pollutant emission was determined by season by comparing the predicted concentration with the measurement one obtained for a year from the late 1996. The results showed that particulate nitrate was the highest in summer but about 40% of total nitrate was present in the gas phase. This was due to volatilization at high temperature since ammonia was sufficient to neutralize all nitrate regardless of season. As relative humidity in summer was higher than the deliquescence point, particulate ion concentration with water was two times higher than that in other season. So called ‘NOx disbenefit’ indicating increase in particulate ion concentration with decrease in NOx emission was evident especially in winter.

• 한국대기환경학회지
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• 제11권1호
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• pp.37-44
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• 1995

Concentration of particulate nitrate classified by formation mechanism and particle diameter 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 N $H_{4}$N $O_{3}$ in TSP was measured by pyrolysis of sample filters at 160.deg.C for 1hr. concentration of N $H_{4}$N $O_{3}$ was higher in winter time compared with that in summmer time. Also, concentration of N $H_{4}$N $O_{3}$ was higher in fine particles compared with that in coarse particle. The range of N $H_{4}$N $O_{3}$ concentration was between 2.9 and 9.9.mu.g/ $m^{3}$. Weight fraction of N $H_{4}$N $O_{3}$ in total particulate nitrate was 31.1 .sim. 59.5%, and weight fraction of N $H_{4}$N $O_{3}$ in TSP was 2.1 .sim. 11.2%. Concentration of NaN $O_{3}$, which originated from sea salt, was highest in spring time and lowest in summer time,and the concentration range was between 0.1 and 0.7.mu.g/ $m^{3}$. NaN $O_{3}$/TSP ratio was very low (0.1 .sim. 0.4%) indicating that the portion of NaN $O_{3}$in TSP was negligible. Concentration of particulate nitrate originated from soil was 2.4 .sim. 2.9.mu.g/ $m^{3}$. Weight fraction of that in total particulate nitrate was 14.0 .sim. 37.1%.

• 한국환경보건학회지
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• 제24권2호
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• pp.32-37
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• 1998

• 한국대기환경학회지
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• 제9권2호
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• pp.154-159
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• 1993

Theoretical prediction of the equilibrium of temperature and relative humidity dependance involving $HNO_{3(g)}-NH_{3(g)}$ and $NH_4NH_{3(s, aq)}$ was compared with atmospheric measurement of particulate nitrate$(NO_3^-)$, Ammonia-Nitric Acid partial pressure product $([$NH_{3(g)}][HNO_{3(g)}]ppb^2$) by a triple filter pack sampler from Oct 1991 to July 1992. The measured $HNO_3NH_3$ concentration product K was greater than equilibrium constant $K_p$ calculated from thermodynamic data of $NH_4NO_{3(s, aq)}-HNO_{3(g)}-NH_{3(g)}$ during fall, winter and spring. But K was lower than $K_p$ in summer. K was greater than $K_p$ as the result of supersaturation by air pollution, particularly anthropogenic $NH_3$.The reason of $K < K_p$ was due to removal of particulate nitrate$(NO_3^-)$ by rainout and washout. $NH_4NO_3$ which consists mainly of particulate nitrate is formed by reaction between $HNO_3$ and $NH_3$. As a result of the removal of particulate nitrate$(NO_3^-)$ by rainout and washout, concentrations of $HNO_3$ and $NH_3$ are decreased by equilibrium transfer(Le Chatelier's Law) in atmosphere.

• 한국대기환경학회지
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• 제2권3호
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• pp.27-33
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• 1986

Atmospheric particulate matter (A. P. M.) was collected and size-fractionated by an Andersen high-volume air sampler over 15 month period from Jan. 1985 to Feb. 1986 in Seoul. The concentration of chloride, nitrate and sulfate were extracted in an ultrasonic bath and were analyzed by ion chromatography. The annual arithmetical mean of A. P. M. was 128.54 $\mug/m^3$. The concentration of anions were 2.88 $\mug/m^3$ for chloride, 3.86$\mug/m^3$ for nitrate, and 25.44$\mug/m^3$ for sulfate. The content of A. P. M. was lowest in the particle size range 1.1 $\sim 3.3\mum$ and increased as the particle size increased or decreased. And the anions exhibited a seasonal variation in the isize distribution. The contents of anions were higher in winter than summer. Ther ratio of fine particles to the total particles defined by F/T for chloride, nitrate and sulfate. The F\ulcornerT of these anion generally decrease with increasing air temperature. This tendency was prevalent in the chloride and nitrate.

• 한국대기환경학회지
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• 제2권1호
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• pp.33-39
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• 1986

Particulate matter was collected by Andersen Air Sampler in the Seoul area during February-October, 1985, in order to investigate size distribution of sulfate and nitrate in aerosol, and conversion of sulfur dioxide to sulfate and that of nitrogen dioxide to nitrate. The size distribution of sulfate and nitrate had fine mode. The ratio of fine sulfate to total sulfate in aerosol and that of fine nitrate to total nitrate showed between 54.6% and 86%, and 55.7% and 95%, respectively, which presumably originated from gaseous reaction of sulfur dioxide and nitrogen dioxide in the atmosphere.

• 한국분무공학회지
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• 제19권3호
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• pp.142-148
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• 2014

In this study, characteristics of gaseous pollutants and particulate matter were investigated on the condition of DPF regeneration and normal DPF condition. THC, CO, $CO_2$, NOx, and $CH_4$ were analyzed by MEXA-7200H and CVS-7100 respectively. Particulate Matter (PM) was measured by difference in weight of Membrane filter. Particle Number (PN) was measured by CPC analyzer. And Sulfate, Nitrate, Organic were measured by Aerosol Mass Spectrometer (AMS). As a result, gaseous pollutants and particulate matter were detected in higher concentration during DPF regeneration than normal DPF condition. And the PN increased by 94%, the fuel consumption was reduced by 29% on DPF generation process. Sulfate, Nitrate and Organic were undetectable level during normal DPF condition. But the highest concentration of Sulfate, Nitrate and Organic were measured as $100{\mu}g/m^3$, $20{\mu}g/m^3$ and $15{\mu}g/m^3$ respectively on DPF regeneration condition. VOCs concentrations (Benzene, Toluene, Ethylbenzene, Xylene) were analyzed by using PTR-MS. Benzene and Toluene emission have little or no change depending on DPF regeneration. But the Ethylbenzene and Xylene have comparatively low emissions on DPF regeneration.

• 한국대기환경학회지
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• 제10권3호
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• pp.191-196
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• 1994

Concentration of particulate nitrate originated from sea salt in ambient air was determined from February to October 1993. Sampling was carried out using a two-stage Anderson air sampler at the top of a five-story building located at Kon-Kuk University in Seoul. Concentration of NaNO$_3$, which originated from sea salt was highest in spring time and lowest in summer the and the concentration range was between 0.10 and 0.66 $\mu\textrm{g}$/㎥. NaNO$_3$/TSP ratio was very low 0.05~0.39%) indicating that the portion of NaNO$_3$ in TSP was negligible.