• Title/Summary/Keyword: VOC-limited regime

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Analysis of Photochemical Ozone Formation Regime in Busan - Comparative Study on Busan vs. Seoul Metropolitan Area(Ⅳ) (부산지역 광화학 오존 생성 regime 분석 - 수도권과 비교연구 (Ⅳ))

  • Seung-Hee Baek;Hyo-Jung Lee;Cheol-Hee Kim
    • Journal of Environmental Science International
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    • v.32 no.5
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    • pp.285-301
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    • 2023
  • This study analyzed characteristics of ozone (O3) formation regimes in Busan over a period of recent five years (2015~2019) and compared the findings with those obtained in Seoul. We employed four observed variations: early morning commuting-hour (i.e., 06:00-09:00 LST) nitrogen dioxide (NO2), peak-hour (i.e., 12:00-16:00 LST) O3, 8-hour average O3 (MDA8 O3), and △O3 (=O3_max- O3_min) in Busan and Seoul. In addition, the NO2-O3 relation was assessed to interpret which of NOx-limited or volatile organic compound (VOC)-limited was dominant. In Busan, the annual mean O3 concentration was relatively higher than in Seoul, whereas there were fewer high-concentration days. The Pearson correlation coefficients (R) between Early morning-hour NO2 and the Peak-hour O3 was positive (but close to zero) in Busan and negative in Seoul. Likewise, the R between the Early morning-hour NO2 and the △O3 showed a relatively considerable positive correlation (R=+0.4~0.5)(R=+0.4~0.5) in Busan, while a weak positive correlation (R=+0.1~0.2) in Seoul. From this result, it can be inferred that the O3 formation regime in Busan was intrepreted to be nearly neutral or relatively closer to the NOx-limited regime than Seoul, while Seoul to the VOC-limited regime. The study findings imply that O3 control strategies should be applied differently in Busan and Seoul. The results here were inferred from surface NO2 and O3 observations, and the varification studies based on in-situ VOCs measurements would be needed.

Characteristics of Ozone Concentration Weekend Effect in Busan Area (부산지역 오존농도의 주말 효과 특성)

  • Jeon, Byung-Il
    • Journal of Environmental Science International
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    • v.23 no.5
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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.

Characteristic Analysis of Tropospheric Ozone Sensitivity from the Satellite-Based HCHO/NO2 Ratio in South Korea (위성 기반 HCHO/NO2 비율을 통한 국내 대류권 오존 민감도 특성 분석)

  • Jinah Jang;Yun Gon Lee ;Jeong-Ah Yu;Kyoung-Hee Sung;Sang-Min Kim
    • Korean Journal of Remote Sensing
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    • v.39 no.5_1
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    • pp.563-576
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    • 2023
  • In this study nitrogen dioxide (NO2), formaldehyde (HCHO) from the Ozone Monitoring Instrument (OMI) and TROPOspheric Monitoring Instrument (TROPOMI), OMI/ Microwave Limb Sounder (MLS) tropospheric column ozone (TCO), and Airkorea ground-based O3 data were analyzed to examine the photochemical reaction relationship between tropospheric ozone and its precursors nitrogen oxides (NOx) and volatile organic compounds (VOCs). As a result of analyzing the trend of long-term changes from 2006 to 2020 using OMI satellite data, TCO showed an increasing trend, NO2 steadily decreased, and HCHO continued to increase in Northeast Asia. In addition, formaldehyde nitrogen dioxide ratio (FNR; HCHO/NO2 ratio), an indicator of ozone sensitivity, is gradually increasing, which means that the VOC-limited regime is decreasing. This study conducted a sensitivity analysis of ozone generation using TROPOMI FNR and ground-based ozone (O3) over the recent years (2019~2022) to identify the possible cause for the continuous increase of ozone in Korea. Similar to the previous studies, VOC-limited and transitional regimes appeared in megacities, and VOC-limited regimes also appeared in areas where major power plants were located. In VOC-limited regimes, in other words, areas where NOx is excessively saturated, the reduction in NOx emissions may have weakened the ozone titration and thus led to the increase of ozone. Therefore, VOC emissions should be reduced in the short term rather than NOx emissions to reduce ozone concentrations under the VOC-limited regime.

Evaluation of Incremental Reactivity and Ozone Production Contribution of VOCs Using the PAMS Data in Seoul Metropolitan Area (수도권에서 오존생성 기여도 산출에 관한 연구)

  • Lee, J.H.;Han, J.S.;Yun, H.K.;Cho, S.Y.
    • Journal of Korean Society for Atmospheric Environment
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    • v.23 no.3
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    • pp.286-296
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    • 2007
  • Ozone creation potentials suited for Seoul metropolitan area was derived by utilizing the PAMS monitoring data and the source inventory. A simple box model with variable height was developed to calculate the incremental reactivity for all the ozone episode days in the year 2003 and 2004. RIR (Relative Incremental Reactivity) was introduced as a measure of contribution to ozone generation in the Seoul metropolitan area. RIR was defined as a function of ratio of VOC to $NO_x$ and therefore it addresses both VOC and $NO_x$ limited regime. For the days that more than 10 monitoring stations out of 27 monitoring station in Seoul recorded the daily maximum ozone concentrations higher than 70 ppb, toluene had the highest RIR value in all the type II and type III PAMS site and m/p-xylene followed with the second highest RIR value. Analyses using MIR (Maximum Incremental Reactivity) and POCP (Photochemical Ozone Creation Potential) instead of RIR also yields dominance of toluene and m/p-xylene in generating ozone concentrations to demonstrate the validity of RIR.