• Journal of Korean Society for Atmospheric Environment
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• v.13 no.5
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• pp.397-410
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• 1997

An annular denuder filter pack sampling system (ADS) was used to collect acidic air pollutants in Pusan. During the study period (from June 1995 to November 1995), forty eight samples were collected every 12 hours starting from 6:00 in the morning. These samples were devided into two sets of data for day (6:00 a.m.-6:00 p.m.) and night (6:00 p.m.-6:00 a.m.). The chemical species were analyzed for HN $O_3$, HN $O_2$, S $O_2$ and N $H_3$ in the gas Phase, and N $O_3$$^{[-10]}$ , S $O_4$$^{2-}$ and N $H_4$$^{+}$ in the particulate phase. The mean concentrations measured from this study were 0.24, 1.91, 30.07 and 4.24 $\mu\textrm{g}$/㎥ for HN $O_3$, HN $O_2$, S $O_2$ and N $H_3$, respectively. The mean concentrations of N $O_3$$^{[-10]}$ , S $O_4$$^{2-}$ and N $H_4$$^+{\ulcorner}$ were 1.95, 7.36 and 3.48 $\mu\textrm{g}$/㎥, respectively. The mean concentrations of gaseous species except for HN $O_2$ were higher in daytime than in nighttime, but the reverse was true in the particulates except for N $H_4$$^{+}$. +/..

• Journal of Korean Society for Atmospheric Environment
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• v.12 no.4
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• pp.441-448
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• 1996

The cyclone/annular denuder system/filter pack sampling system (ADS) was used to collect the acidic air pollutants in Chongju city. The data set was collected on nine different days with 24 hour sampling period from July 27 through August 27, 1995. The chemical species measured were $HNO_3, HNO_2, SO_2 and NH_3$ in the gas phase, and $PM_{2.5}(d_P<2.5 \mum), SO_4^{2-}, NO_3^- and NH_4^+$ in the particulate phase. Mean concentrations measured from this study were: $0.90 \mug/m^3 for HNO_3, 1.27 \mug/m^3 for HNO_2, 10.9 \mug/m^3 for SO_2, 4.82 \mug/m^3 for NH_3, 27.5 \mug/m^3 for PM_{2.5}, 5.24 \mug/m^3 for SO_4^{2-}, 1.22 \mug/m^3 for NO_3^-, and 1.64 \mug/m^3 for NH_4^+$. The fine particle $(PM_{2.5})$ mass measured for the ADS samples was slightly higher than the fine particle mass measured for the corresponding dichotomous sampler. For the wind coming from Chongju industrial complex the concentrations of acidic air pollutants measured were higher when compared with other directions. Specially, $SO_2 and PM_{2.5}$ concentrations for the wind coming from Chongju industrial complex were 3.6 and about 2 times, respectively, higher than those of other wind directions. High correlations were observed between $PM_{2.5} and fine particle's ion components $(r=0.82 with SO_4^{2-}, r=0.76 with NO_3^- and r=0.89 with NH_4^+). NH_4^+ and SO_4^{2-}$ was also highly correlated (r=0.97).

• Journal of Environmental Science International
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• v.4 no.1
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• pp.53-62
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• 1995

To collect and evaluate an aerosol acidity ($H^+$) in ambient air, the cyclone/annular denuder/filter pack sampling system (ADS) was used. Aerosol acidity was collected in Chicago using the ADS for 81 12-hr samples divided in spring/summer/fall 1990 and winter 1991. This study illustrated that the ADS was suitable for measuring aerosol acidity. The $10^{-5}N$ $HCIO_4$ extraction solution for pH determination provided more reliable scale than $10^{-4}N$ HClO4. NH3 should be removed prior to particle collection to accurately measure $H^+$ concentration on the filter. There was seasonal variation in aerosol acidity concertrations. Aerosols were more acidic in the summer. High correlations between $SO_4^{2+} and$NH_4^+$, and between TEX>$SO_4^{2+}$H^+$ were observed during the entire sampling period.

• Journal of Korean Society for Atmospheric Environment
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• v.18 no.4
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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.

• Journal of Korean Society for Atmospheric Environment
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• v.15 no.3
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• pp.305-315
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• 1999

The annular denuder system(ADS) was used to determine characteristics of acidic air pollutants and $PM_{2.5}$ species in Seoul-metropolitan areas. All measurements were done simultaneously in downtown(Kwanghwamun, Mullae, Chamshil, Ssangmun dongs) and outskirts(Puch n, Kuri cities) during four seasons. The samples were analyzed using ion chromatography for gas-phase matters(HCl, $HNO_2$, $HNO_3$ and $SO^2$) and particulate phase matters($Cl^-$, $NO^{2-}$, $NO_3^-$, $SO_4^{2-}$, $Na^+$, $NH_4^-$ and $Ca^{2+}$) and was measured fine particles($PM_{2.5}$). The seasonal mean concentrations of HCl, HNO2, HNO3 and SO2 in downtown and outskirt areas were very similar. All chemical species monitored from this study showed seasonal variations. Nitric acid(HNO3) and Nitrous acid(HNO2) were showed higher concentrations during the summer. $PM_{2.5}$, $SO_4^{2-}$, $NH_4^-$, $NO_3^-$ and $Cl^-$ in the particulate phase matters were higher levels during the winter months. The concentrations of these components were 54.8, 3.82, 2.49, 1.80 and 1.02$\mu\textrm{g}$/㎥, respectively.

• Journal of Korean Society for Atmospheric Environment
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• v.15 no.2
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• pp.113-120
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• 1999

Winter and summer samples were collected from January 3 to February 7, 1997 and July 26 to September 11, 1997, respectively, in Seoul. This study was to characterize the concentrations of the annular denuder system (ADS) were $HNO_3$, $HNO_2$, $SO_2$ and $NH_3$ in the gas phase, and $PM_{2.5}$ ($d_p$〈2.5$mu extrm{m}$), $SO_4^{2-}$, NO3-, and $NH_4^+$ in the particulate phase. All chemical species monitored from this study showed statistical seasonal variations except for $SO_4^{2-}$ . Nitric acid (HNO3) and ammonia ($NH_3$) exhibited substantially higher concentrations during the summer, while nitrous acid ($HNO_2$) and sulfur dioxide ($SO_2$) concentrations were higher during the winter. $PM_{2.5}$, $NO_3^-$, and $NH_4^+$ were higher leves in the winter. High correlations were found among $PM_{2.5}$, $NO_3^-$ $SO_4^{2-}$ and $NH_4^+$ during two seasons.

• Journal of Korean Society for Atmospheric Environment
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• v.13 no.5
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• pp.333-343
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• 1997

The cyclone/annular denuder system/filter pack sampling system (ADS) was used to collect the acidic air pollutants in Chongju city. The data set was collected on fifty -eight different days with 24 hour sampling period from October 27, 1995 through August 25, 1996. The chemical species measured were HN $O_3$, HN $O_2$, S $O_2$ and N $H_3$ in the gas phase, and PM2.5( $d_{p}$ ＜2.5 ${\mu}{\textrm}{m}$), S $O_4$$^{2-}$, N $O_3$$^{[-10]}$ and N $H_4$$^{+}$ in the Particulate Phase. Mean concentrations measured for this study were: 0.45 $\mu\textrm{g}$/㎥ for HN $O_3$, 3.39 $\mu\textrm{g}$/㎥ for HN $O_2$, 26.4 $\mu\textrm{g}$/㎥ for S $O_2$, 3.83$\mu\textrm{g}$/㎥ for N $H_3$, 44.2 $\mu\textrm{g}$/㎥ for P $M_{2.5}$, 8.22 $\mu\textrm{g}$/㎥ for S $O_4$$^{2-}$, 3.63 $\mu\textrm{g}$/㎥ for N $O_3$$^{[-10]}$ , and 2.84 $\mu\textrm{g}$/㎥ for N $H_4$$^{- }$. HN $O_3$ and N $H_3$ were higher during the summer. However, HN $O_2$ and S $O_2$ were higher during the fall and winter. P $M_{2.5}$ , S $O_4$/ sup 2-/ and N $H_4$$^{+}$ were not showed seasonal variations, but N $O_3$$^{[-10]}$ was higher in the winter.ter.r.

• Journal of Korean Society for Atmospheric Environment
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• v.17 no.2
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• pp.193-201
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• 2001

Acidic air pollutants were collected to characterize indoor air quality in a residential area in the summer. All indoor and outdoor samples were measured simultaneously using an annular denuder system(ADS) in Seoul. The data set was collected from July 26 to September 11, 1997. The mean indoor/outdoor ratios measured from this study were : 0.34 for $HNO_3$; 0.91 for $HNO_2$; 0.22 for $SO_2$; 1.34 for $NH_3$; 0.78 for $PM_{2.5}(d_p$ <2.5 $mutextrm{m}$); 0.90 for $SO_{4}^{2-}$; 0.68 for $NO_{3}^{-}$ and 0.79 for $NH_{4}^{+}$. Indoor concentrations of $HNO_3$, $SO_2$ and $PM_{2.5}$ were highly correlated with the outdoor concentrations. The relationship between indoor and outdoor air is dependent, to a large extent, on the rate of air exchange between these two environments. A tracer-gas decay technique with sulfur hexafluoride ($SF_{6}$) as a tracer gas was used to estimate the air exchange of a private home in the summer. The average air exchange rate was estimated to be 23.7 hr(sup)-1. The deposition velocities for $SO_{4}^{2-}$, $NO_{3}^{-}$ and $NH_{4}^{+}$ calculated were 0.17, 0.69 abd 0.39 cm/sec, respectively.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.5
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• pp.613-621
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• 2008

The purpose of this study is to understand the impact that temperature and relative humidity have on the volatilization loss of particulate nitrate $(NO_3^-)$ from Teflon filters during measurements of ambient fine particles $(PM_{2.5})$. Fine particles $(d_p<2.5{\mu}m)$ were measured using an annular denuder system (ADS) at four representive areas in Seoul. The measurements were made during 28 different days at 24-hr sampling intervals from February 14 to October 15, 1997. In this study, nitrate losses. calculated by the ratio of nitrate on the nylon filter to their sum in both Teflon and nylon titters, varied seasonally in the following order: summer (45.5%) > spring (23.8%) > fall (20.6%) > winter (19.7%). The results showed strong correlations with temperature, but we did not observe any significant effects of relative humidity. However, we observed that both temperature and relative humidity influenced the ambient gas/particle nitrate ratio in a different case study using a denuder.

• Journal of Korean Society for Atmospheric Environment
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• v.27 no.1
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• pp.16-29
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• 2011

The cyclone/annular denuder system/filter pack sampling system (ADS) was used to collect data set of the acidic air pollutants in the vicinity of industrial complexes in Gwangyang. The data set was collected during sixty different days with 24 hour sampling period from January 8, 2008 through November 12, 2008. The annual mean concentrations of $HNO_3$, $HNO_2$, $SO_2$ and $NH_3$ in the gas phase were 1.12, 1.40, 10.2 and 1.28 ${\mu}g/m^3$, respectively. The annual mean concentrations of $PM_{2.5}$ ($d_p$<2.5 ${\mu}m$), $SO_4^{2-}$, $NO_3^-$, and $NH_4^+$ in the particulate phase were 29.2, 8.25, 3.30 and 3.42${\mu}g/m^3$, respectively. $HNO_3$ and $NH_3$ exhibited higher concentrations during the summer, while $HNO_2$, $PM_{2.5}$, $NO_3^-$ and $NH_4^+$ were higher during the winter. The highest level of $SO_2$ was, unlikely, observed in the summer and $SO_4^{2-}$ was not showed seasonal variation. $SO_4^{2-}$, $NO_3^-$, and $NH_4^+$ accounted for 49~57% of the $PM_{2.5}$ mass. $SO_4^{2-}$ was the most abundant component, which constituted 23~40% of $PM_{2.5}$. High correlations were found among $PM_{2.5}$, $SO_4^{2-}$, $NO_3^-$, and $NH_4^+$.