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A Test of NDIR-based Sensors for the Near Real-time Analysis of CO₂
Sudhir Kumar Pandey,Ki-Hyun Kim 한국대기환경학회 2007 한국대기환경학회 학술대회논문집 Vol.- No.-
In this study, the reliability of NDIR-based sensors wasexplored by evaluating the comparability between measurement systems in the near real-time analysis of CO₂. For this purpose, replicate analyses were performed using sensors of two different model types(H-550 and B-530, ELT Company, Korea). Three replicate data of each sensor type collected continuously by side-by-side analysis in three second intervals(a duration of 304 hour) were evaluated for the relative performance of NDIR sensors. The reproducibility of sensors, when assessed by relative standard error(RSE %) values of all sensor units, showed moderate changes with time with the overall mean of 2.33%. When CO₂ measurements from all NDIR sensor units were evaluated by correlation analysis, the results showed strong comparability, regardless of the model type. The overall results of this study suggest that NDIR sensors are reliable enough to produce highly comparable data at least in a relative sense.
A review of environmental tobacco smoke and its determination in air
Pandey, Sudhir Kumar,Kim, Ki-Hyun Elsevier 2010 Trends in analytical chemistry Vol.29 No.8
<P><B>Abstract</B></P><P>In this review, we discuss methodological approaches commonly employed for the determination of chemical components in environmental tobacco smoke (ETS). Considering its compositional diversity and significant impact on human health, ETS analysis is important. Here we describe it along with the methodologies commonly available for smoke generation, sampling, and preconcentration of ETS components.</P><P>We evaluate the performance of each experimental approach in terms of basic quality assurance. To this end, we emphasize gas chromatography-based detection methods by comparing absolute detectability and analytical feasibility for the most common ETS markers in a practical sense. Finally, we highlight the limitations and the future prospects in the study of ETS.</P>
Measurement techniques for mercury species in ambient air
Pandey, Sudhir Kumar,Kim, Ki-Hyun Elsevier 2011 Trends in analytical chemistry Vol.30 No.6
<P><B>Abstract</B></P><P>This review critically evaluates the measurement methodologies most commonly employed for the analysis of the various forms of mercury (Hg) in air. Emphasis is given to the three most common forms of mercury in air [i.e. gaseous elemental mercury (GEM, Hg<SUP>0</SUP>), reactive gaseous mercury (RGM), and particle-bound mercury (Hg<SUB>p</SUB>)]. Moreover, we also briefly describe methods dealing with gas-phase analysis of organic mercury species (e.g., mostly methyl mercury), as they are also reported to be present in air on rare occasions. To begin with, we describe the approaches to sampling airborne mercury species and associated sample-treatment strategies. We evaluate both conventional and emerging alternative detection techniques for different mercury forms with respect to their applicability in airborne mercury analysis. We also discuss the artifacts and the biases associated with analysis of different mercury species. Finally, the review summarizes current methodological developments for the determination of mercury in air and highlights future prospects for improvements.</P>
Pandey, Sudhir Kumar,Kim, Ki-Hyun Elsevier 2009 Journal of chromatography A Vol.1216 No.28
<P><B>Abstract</B></P><P>In this study, the feasibility of GC–MS was evaluated for the quantification of odorous volatile organic compounds (VOCs) in environmental samples. These included methyl ethyl ketone, isobutyl alcohol, methyl isobutyl ketone, and butyl acetate plus benzene, toluene, and xylene (BTX). For this purpose, the gaseous standard for these VOCs were analyzed by GC–MS with the aid of both direct injection (DI) into the GC injector and solid-phase microextraction (SPME). The liquid phase standard prepared independently was tested additionally by the DI method as a reference to gaseous calibration. The detection limit (DL) values, when tested for basic quality assurance in this study, showed large differences between DI (0.002–0.007ng) and SPME method (1.03–1.81ng) in terms of absolute mass. The DL values, when expressed in terms of concentration (v/v), showed considerable improvement in SPME (below 0.40nmolmol<SUP>−1</SUP>) relative to the DI method (∼6–15 nmolmol<SUP>−1</SUP>). The reliability of the GC–MS method was further validated through an analysis of real environmental samples collected from an industrial area.</P>
Pandey, Sudhir Kumar,Kim, Ki-Hyun TheScientificWorldJOURNAL 2010 The Scientific World Journal Vol.10 No.-
<P>In this study, the contents of nicotine and volatile organic compounds (VOCs) in mainstream smoke (MSS) were analyzed using samples of four cigarette types consisting of two common brands (R and E) with full (F) and light (L) flavor, coded with R-F, R-L, E-F, and E-L. These cigarettes were also analyzed after removing the filter portions with the assignment of a new sample code of (N) as the third letter (e.g., R-L-N). A total of 44 VOCs (including nicotine) were quantified by the combination of the SPME and GC-MS methods. Out of the 44 VOCs, 10 were identified as hazardous air pollutants listed by the U.S. EPA, while their concentrations exceeded the reference exposure limits set by various agencies. A clear distinction was apparent in the concentration levels of VOCs between different brands or between full and light flavors. Nicotine concentrations varied greatly between different cigarettes types of the R brand, whereas such changes were insignificant in the counterpart E brand. This thus suggests that light-flavor cigarettes do not necessarily guarantee low doses of carcinogens (and tar) than regular cigarettes, as their differences can be balanced by the inhaling behavior of the smoker.</P>
Bio-filters for the Treatment of VOCs and Odors - A Review
Kumar Vikrant,김기현,Jan Edward Szulejko,Sudhir Kumar Pandey,R.S. Singh,B.S. Giri,Richard J. C. Brown,이상훈 한국대기환경학회 2017 Asian Journal of Atmospheric Environment (AJAE) Vol.11 No.3
Excessive amounts of volatile organic compounds (VOCs) and odorants discharged into the environment are highly dangerous to human health as well as to ecological systems. Biological treatments of waste gas streams, called biofiltration, containing VOCs and odorous compounds has gained much attention because biofilters are more cost effective and environmentally friendly than conventional air pollution control technologies. This review provides an overview of biotrickling filtration, which is a type of biofiltration including continuous trickled-water flow inside filter media, for VOC and odor abatement. The configuration, design, cost effectiveness, removal capacity and environmental impact of this techniques and the future research and development needs in this area are all considered.