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We present trace gas vertical profiles observed by instruments on the NASA DC-8 and at a ground site during the Korea-US air quality study (KORUS) field campaign in May to June 2016. We focus on the region near the Seoul metropolitan area and its surroundings where both anthropogenic and natural emission sources play an important role in local photochemistry. Integrating ground and airborne observations is the major research goal of many atmospheric chemistry field campaigns. Although airborne platforms typically aim to sample from near surface to the free troposphere, it is difficult to fly very close to the surface especially in environments with complex terrain or a populated area. A detailed analysis integrating ground and airborne observations associated with specific concentration footprints indicates that reactive trace gases are quickly oxidized below an altitude of 700 m. The total OH reactivity profile has a rapid decay in the lower part of troposphere from surface to the lowest altitude (700 m) sampled by the NASA DC-8. The decay rate is close to that of very reactive biogenic volatile organic compounds such as monoterpenes. Therefore, we argue that photochemical processes in the bottom of the boundary layer, below the typical altitude of aircraft sampling, should be thoroughly investigated to properly assess ozone and secondary aerosol formation.

Behavior coding is used to detect issues in questionnaires by flagging interactions between survey respondents and interviewers when their interactions deviate from standardized interviewing. It has become a popular method for evaluating survey questionnaire quality and has been used mostly in Western countries, with little research being done in Asia. However, because of its dependence on overt behaviors observed during the coding, it was hypothesized that it might not be as effective in a country where different communicative norms are present. We conducted an experiment in Korea using two sets of survey questionnaires with embedded problematic questions in the experimental group to investigate the validity of behavior coding as reference to the control group. Using 200 audio recordings from a telephone survey, we investigated whether behavior-coded data were helpful in identifying embedded flaws. The results indicated behavior coding in Korean surveys may not be as effective as in Western countries.

When recruiting respondents for cognitive interviews testing translated survey questionnaires, researchers often recommend interviewing monolingual non-English speakers because they are the likely users of the translations. However, these individuals are hard to recruit, and there is no standard definition of monolingual. Using cognitive interview data collected from pretesting of Chinese and Korean translations of the American Community Survey Language Assistance Guide, we investigated whether there were differences in respondents' understanding of survey questions according to their level of English proficiency and if such differences remained after considering demographic characteristics. We found that the types of issues reported by monolingual speakers and partially bilingual speakers were similar and that differences seemed to be driven by different demographic characteristics and not necessarily by language proficiency. Our findings suggest the value of evaluating translated questionnaires with individuals having diverse demographic characteristics and recruiting both monolingual speakers and partially bilingual speakers as research participants.

Featured Application: The results of this paper can be instrumental in establishing insulation material management standards for determining the stable operation condition of XLPE cables in the future. Cross-linked polyethylene (XLPE) cable is a representative power transmission cable. XLPE has excellent mechanical properties, chemical and heat resistance, and insulation. However, XLPE insulation deteriorates during operation due to electrical, mechanical, and thermal stresses. Among these, thermal stress is a major factor and reduces insulation properties due to a change in molecular structure. Therefore, XLPE characteristic evaluation by heat exposure is essential for power cable condition evaluation. Herein, deteriorated XLPE samples were characterized by tensile strength, X-ray diffraction, Fourier-transform infrared spectroscopy, differential scanning calorimetry, and ultraviolet-visible spectroscopy after exposure to various temperatures and durations. Comparing the tensile strength with other analysis results yielded correlations. Each characteristic showed a linear relationship. The correlation between tensile strength and carbonyl index was the strongest, and the coefficient of determination, R2, was 0.9299. Therefore, these results will provide important information on chemical properties when establishing operational management standards for XLPE insulators in the future. [ABSTRACT FROM AUTHOR]

Furfural is an intermediary and aldehyde compound degraded from paper insulation, which is used with liquid fluid in power transformers. It can be utilized as an important indicator to evaluate the degradation degree of the paper insulation and the condition of transformers to predict their lifetime. However, the conventional methods are inevitably inconvenient as they require additional derivatization with hazardous agents and time-consuming chromatographic separation and processes. In this work, a facile and green analysis method for the determination of furfural concentration in the insulating fluid of operating power transformers was developed. As furfural was selectively extracted from the insulting fluid by deionized water, the aqueous solution could be directly subjected to a UV spectral analysis without any derivatization using hazardous agents or hindrance of the fluid in the UV spectrum. The results showed that the spectral method could obtain a favorable linear relationship between the concentration of furfural and its characteristic absorbance at 280 nm (λ max). The limit of detection (LOD) was below 0.1 ppm, which is a sufficient detection level to evaluate the condition of the insulating fluid. Furthermore, the method was compared with the conventional HPLC and colorimetric analyses, revealing satisfactory accuracy and verification of the results. It is possible to measure the furfural concentration in situ using a portable UV-spectrometer at a single wavelength, 280 nm, after simple extraction in the field. This approach offers a novel and green analytical method to quantitatively determine the aromatic furan compounds in a power transformer's insulating fluid in place without the use of an organic extraction solvent or hazardous reagents for derivatization and analysis. [ABSTRACT FROM AUTHOR]