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RISS 인기검색어
- 검색키워드
- 저자 : Norimichi Takenaka (검색결과 2 건)
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Simultaneous Sampling of NO, NO2, HONO and HNO3 in the Atmosphere by a Filter-Pack Method
Norimichi Takenaka,Takumi Oda,Yusuke Fujii 한국대기환경학회 2022 Asian Journal of Atmospheric Environment (AJAE) Vol.16 No.2
A simultaneous sampling method for gaseous nitric oxide (NO), nitrogen dioxide (NO2), nitrous acid (HONO) and nitric acid (HNO3) was developed by a filter-pack sampling method to measure these concentrations at low cost in areas where monitoring stations are not available or at multiple locations. HONO and HNO3 gases were collected with a conventional filter-pack method. NO2 was collected with a guaiacolimpregnated filter at a flow rate of 0.3 dm3 min-1. NO was collected using guaiacol by oxidizing it to NO2 with potassium permanganate at a 0.3 dm3 min-1 flow rate. The optimum concentration of KMnO4 in the immersion solution for the impregnated filter was 0.16 mol dm-3 (in 0.51 mol dm-3 H2SO4). The concentrations of NO and NO2 measured by the filter-pack method were in good agreement with those measured by the chemiluminescence method. It was calculated that 60 ppb NO could be oxidized to NO2 with the KMnO4-impregnated filter for 183 hours at a 0.3 dm3 min-1 flow rate. This is enough time for sampling in a real environment. This method was applied to measure NO, NO2, HONO and HNO3 in the atmosphere at three points around Osaka, Japan.
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Source apportionment of ambient PM2.5 in Ho Chi Minh City, Vietnam
Ngoc Tran,Yusuke Fujii,Md Firoz Khan,To Thi Hien,Tran Hoang Minh,Hiroshi Okochi,Norimichi Takenaka 한국대기환경학회 2024 Asian Journal of Atmospheric Environment (AJAE) Vol.18 No.1
The emission sources of fine particulate matter ( PM2.5) have not yet been fully identified in Ho Chi Minh City (HCMC), Vietnam, presenting difficulties to authorities in controlling air pollution efficiently. To address this issue, this study explores the source apportionment of PM2.5 by the positive matrix factorization (PMF) model and identifies potential regional sources through the weighted concentration-weighted trajectory (WCWT) model based on the field observation data of PM2.5 in HCMC. 24-h PM2.5 samples were collected in central HCMC for a year (September 2019–August 2020). Herein, inductively coupled plasma mass spectroscopy was used to analyze trace elements, in addition to identifying PM2.5 mass and other chemical species, such as water-soluble ions and carbonaceous species, reported in our former study. The PMF results showed that PM2.5 in HCMC was dominated by anthropogenic-rich sources comprising biomass burning, coal combustion, transportation, and crustal origins (36.4% of PM2.5 mass), followed by secondary ammonium sulfate (18.4%), sea salt (13.7%), road dust (9.6%), and coal and crude oil combustion (9.4%). WCWT results suggested that the geological sources of PM2.5 were mainly from local areas and scattered to the northeast/southwest of HCMC. In addition, the long-range transport of PM2.5 from surrounding countries was revealed during the assembly restriction and lockdown period in 2020.
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